Merge remote-tracking branch 'upstream/master'

.mailmap

@@ -172,4 +172,45 @@ zhongsp <patrick.zhongsp@gmail.com> # Patrick Zhong
 T18970237136 <T18970237136@users.noreply.github.com> # @T18970237136
 JBerger <JBerger@melco.com>
 bootstraponline  <code@bootstraponline.com> # @bootstraponline
-yortus  <yortus@gmail.com> # @yortus
+yortus  <yortus@gmail.com> # @yortus
+András Parditka  <andraaspar@gmail.com>
+Anton Khlynovskiy  <subzey@gmail.com>
+Charly POLY  <cpoly55@gmail.com>
+Cotton Hou  <himcotton@gmail.com>
+Ethan Resnick  <ethan.resnick@gmail.com>
+Marius Schulz  <marius.schulz@me.com>
+Mattias Buelens  <mattias.buelens@gmail.com>
+Myles Megyesi  <mylesmegyesi@users.noreply.github.com>
+Tim Lancina  <tim@ionic.io>
+Aaron Holmes <aaron@aaronholmes.net> Aaron Holmes <aholmes@bltomato.com>
+Akshar Patel <akshar.patel.47@gmail.com>
+Ali Sabzevari <alisabzevari@gmail.com>
+Aliaksandr Radzivanovich <aradzivanovich@gmail.com>
+BuildTools <FranklinWhale@users.noreply.github.com> # Franklin Tse
+ChogyDan <danielhollocher@gmail.com> # Daniel Hollocher
+Daniel Rosenwasser <DanielRosenwasser@users.noreply.github.com> Daniel Rosenwasser <drosen@microsoft.com>
+David Kmenta <david.kmenta@lmc.eu>
+E020873 <nicolas.henry-partner@arcelormittal.com> # Nicolas Henry
+Elisée Maurer <elisee@sparklinlabs.com>
+Emilio García-Pumarino <emili.tfe@gmail.com> dashaus <emili.tfe@gmail.com>
+Guilherme Oenning <me@goenning.net>
+Herrington Darkholme <nonamesheep1@gmail.com>
+Ivo Gabe de Wolff <ivogabe@ivogabe.nl>
+Joey Wilson <joey.wilson.a@gmail.com>
+Jonathon Smith <failing@crashdive.co.uk>
+Juan Luis Boya García <ntrrgc@gmail.com>
+Kagami Sascha Rosylight <saschanaz@outlook.com>
+Lucien Greathouse <me@lpghatguy.com>
+Martin Vseticka <vseticka.martin@gmail.com>
+Mattias Buelens <mattias.buelens@opentelly.com>
+Michael Bromley <michael@michaelbromley.co.uk>
+Paul Jolly <paul@myitcv.org.uk>
+Perry Jiang <jiangperry@gmail.com>
+Peter Burns <rictic@google.com>
+Robert Coie <rac@intrigue.com>
+Thomas Loubiou <t.loubiou@systonic.fr>
+Tim Perry <tim.perry@softwire.com>
+Vidar Tonaas Fauske <vidartf@gmail.com>
+Viktor Zozulyak <zozulyakviktor@gmail.com>
+rix <rix@rixs-MacBook-Pro.local> # Richard Sentino
+rohitverma007 <rohitverma@live.ca> # Rohit Verma

.npmignore

@@ -1,8 +1,11 @@
 built
 doc
+Gulpfile.ts
 internal
 issue_template.md
+jenkins.sh
 lib/README.md
+netci.groovy
 pull_request_template.md
 scripts
 src

.travis.yml

@@ -2,6 +2,7 @@ language: node_js
 
 node_js:
   - 'stable'
+  - '6'
   - '4'
 
 sudo: false

AUTHORS.md

@@ -1,17 +1,23 @@
 TypeScript is authored by:
+* Aaron Holmes
 * Abubaker Bashir
 * Adam Freidin
 * Adi Dahiya
 * Ahmad Farid
+* Akshar Patel
 * Alex Eagle
 * Alexander Kuvaev
 * Alexander Rusakov 
+* Ali Sabzevari
+* Aliaksandr Radzivanovich
 * Anatoly Ressin 
 * Anders Hejlsberg
 * Andrej Baran 
 * Andrew Z Allen
+* András Parditka 
 * Andy Hanson
 * Anil Anar
+* Anton Khlynovskiy 
 * Anton Tolmachev
 * Arnav Singh
 * Arthur Ozga
@@ -27,16 +33,20 @@ TypeScript is authored by:
 * Brett Mayen
 * Bryan Forbes
 * Caitlin Potter
+* Charly POLY 
 * Chris Bubernak
 * Christophe Vidal 
 * Chuck Jazdzewski
 * Colby Russell
 * Colin Snover
+* Cotton Hou 
 * Cyrus Najmabadi
 * Dafrok Zhang
 * Dan Corder
 * Dan Quirk
+* Daniel Hollocher
 * Daniel Rosenwasser
+* David Kmenta
 * David Li
 * David Souther
 * Denis Nedelyaev
@@ -45,8 +55,11 @@ TypeScript is authored by:
 * Dirk Holtwick
 * Dom Chen 
 * Doug Ilijev
+* Elisée Maurer
+* Emilio García-Pumarino
 * Eric Tsang
 * Erik Edrosa
+* Ethan Resnick 
 * Ethan Rubio
 * Evan Martin
 * Evan Sebastian
@@ -54,12 +67,14 @@ TypeScript is authored by:
 * Fabian Cook 
 * @falsandtru
 * Frank Wallis
+* Franklin Tse
 * František Žiacik
 * Gabe Moothart 
 * Gabriel Isenberg
 * Gilad Peleg
 * Godfrey Chan 
 * Graeme Wicksted
+* Guilherme Oenning
 * Guillaume Salles
 * Guy Bedford
 * Harald Niesche
@@ -78,12 +93,14 @@ TypeScript is authored by:
 * Jeffrey Morlan
 * Jesse Schalken
 * Jiri Tobisek
+* Joey Wilson
 * Johannes Rieken
 * John Vilk
 * Jonathan Bond-Caron
 * Jonathan Park
 * Jonathan Toland
 * Jonathan Turner
+* Jonathon Smith
 * Josh Abernathy 
 * Josh Kalderimis
 * Josh Soref
@@ -102,15 +119,21 @@ TypeScript is authored by:
 * Lucien Greathouse
 * Lukas Elmer 
 * Marin Marinov
+* Marius Schulz 
 * Martin Vseticka
 * Masahiro Wakame
 * Matt McCutchen
+* Mattias Buelens
+* Mattias Buelens 
 * Max Deepfield
 * Micah Zoltu
 * Michael 
+* Michael Bromley
 * Mohamed Hegazy
+* Myles Megyesi 
 * Nathan Shively-Sanders
 * Nathan Yee
+* Nicolas Henry
 * Nima Zahedi
 * Noah Chen 
 * Noj Vek
@@ -119,9 +142,12 @@ TypeScript is authored by:
 * Omer Sheikh 
 * Oskar Segersva¨rd
 * Patrick Zhong
+* Paul Jolly
 * Paul van Brenk
 * @pcbro
 * Pedro Maltez
+* Perry Jiang
+* Peter Burns
 * Philip Bulley
 * Piero Cangianiello
 * @piloopin
@@ -130,6 +156,9 @@ TypeScript is authored by:
 * Punya Biswal
 * Rado Kirov
 * Richard Knoll
+* Richard Sentino
+* Robert Coie
+* Rohit Verma
 * Ron Buckton
 * Rostislav Galimsky 
 * Rowan Wyborn
@@ -152,7 +181,9 @@ TypeScript is authored by:
 * @T18970237136
 * Tarik Ozket
 * Tetsuharu Ohzeki
+* Thomas Loubiou
 * Tien Hoanhtien
+* Tim Lancina 
 * Tim Perry
 * Tim Viiding-Spader
 * Tingan Ho
@@ -161,6 +192,8 @@ TypeScript is authored by:
 * Tomas Grubliauskas
 * Torben Fitschen 
 * TruongSinh Tran-Nguyen
+* Vidar Tonaas Fauske
+* Viktor Zozulyak
 * Vilic Vane
 * Vladimir Matveev
 * Wesley Wigham

Gulpfile.ts

@@ -128,7 +128,8 @@ const es2016LibrarySourceMap = es2016LibrarySource.map(function(source) {
 
 const es2017LibrarySource = [
     "es2017.object.d.ts",
-    "es2017.sharedmemory.d.ts"
+    "es2017.sharedmemory.d.ts",
+    "es2017.string.d.ts",
 ];
 
 const es2017LibrarySourceMap = es2017LibrarySource.map(function(source) {
@@ -176,7 +177,7 @@ for (const i in libraryTargets) {
 const configureNightlyJs = path.join(scriptsDirectory, "configureNightly.js");
 const configureNightlyTs = path.join(scriptsDirectory, "configureNightly.ts");
 const packageJson = "package.json";
-const programTs = path.join(compilerDirectory, "program.ts");
+const versionFile = path.join(compilerDirectory, "core.ts");
 
 function needsUpdate(source: string | string[], dest: string | string[]): boolean {
     if (typeof source === "string" && typeof dest === "string") {
@@ -284,7 +285,7 @@ gulp.task(configureNightlyJs, false, [], () => {
 
 // Nightly management tasks
 gulp.task("configure-nightly", "Runs scripts/configureNightly.ts to prepare a build for nightly publishing", [configureNightlyJs], (done) => {
-    exec(host, [configureNightlyJs, packageJson, programTs], done, done);
+    exec(host, [configureNightlyJs, packageJson, versionFile], done, done);
 });
 gulp.task("publish-nightly", "Runs `npm publish --tag next` to create a new nightly build on npm", ["LKG"], () => {
     return runSequence("clean", "useDebugMode", "runtests", (done) => {

Jakefile.js

@@ -71,6 +71,7 @@ var compilerSources = [
     "transformers/destructuring.ts",
     "transformers/ts.ts",
     "transformers/jsx.ts",
+    "transformers/esnext.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",
@@ -107,6 +108,7 @@ var servicesSources = [
     "transformers/destructuring.ts",
     "transformers/ts.ts",
     "transformers/jsx.ts",
+    "transformers/esnext.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",
@@ -248,13 +250,14 @@ var harnessSources = harnessCoreSources.concat([
     "convertToBase64.ts",
     "transpile.ts",
     "reuseProgramStructure.ts",
+    "textStorage.ts",
     "cachingInServerLSHost.ts",
     "moduleResolution.ts",
     "tsconfigParsing.ts",
     "commandLineParsing.ts",
     "configurationExtension.ts",
     "convertCompilerOptionsFromJson.ts",
-    "convertTypingOptionsFromJson.ts",
+    "convertTypeAcquisitionFromJson.ts",
     "tsserverProjectSystem.ts",
     "compileOnSave.ts",
     "typingsInstaller.ts",
@@ -301,7 +304,8 @@ var es2016LibrarySourceMap = es2016LibrarySource.map(function (source) {
 
 var es2017LibrarySource = [
     "es2017.object.d.ts",
-    "es2017.sharedmemory.d.ts"
+    "es2017.sharedmemory.d.ts",
+    "es2017.string.d.ts",
 ];
 
 var es2017LibrarySourceMap = es2017LibrarySource.map(function (source) {
@@ -349,19 +353,16 @@ function prependFile(prefixFile, destinationFile) {
 // concatenate a list of sourceFiles to a destinationFile
 function concatenateFiles(destinationFile, sourceFiles) {
     var temp = "temptemp";
-    // Copy the first file to temp
-    if (!fs.existsSync(sourceFiles[0])) {
-        fail(sourceFiles[0] + " does not exist!");
-    }
-    jake.cpR(sourceFiles[0], temp, { silent: true });
     // append all files in sequence
-    for (var i = 1; i < sourceFiles.length; i++) {
+    var text = "";
+    for (var i = 0; i < sourceFiles.length; i++) {
         if (!fs.existsSync(sourceFiles[i])) {
             fail(sourceFiles[i] + " does not exist!");
         }
-        fs.appendFileSync(temp, "\n\n");
-        fs.appendFileSync(temp, fs.readFileSync(sourceFiles[i]));
+        if (i > 0) { text += "\n\n"; }
+        text += fs.readFileSync(sourceFiles[i]).toString().replace(/\r?\n/g, "\n");
     }
+    fs.writeFileSync(temp, text);
     // Move the file to the final destination
     fs.renameSync(temp, destinationFile);
 }
@@ -590,7 +591,7 @@ task("generate-diagnostics", [diagnosticInfoMapTs]);
 var configureNightlyJs = path.join(scriptsDirectory, "configureNightly.js");
 var configureNightlyTs = path.join(scriptsDirectory, "configureNightly.ts");
 var packageJson = "package.json";
-var programTs = path.join(compilerDirectory, "program.ts");
+var versionFile = path.join(compilerDirectory, "core.ts");
 
 file(configureNightlyTs);
 
@@ -606,7 +607,7 @@ task("setDebugMode", function () {
 });
 
 task("configure-nightly", [configureNightlyJs], function () {
-    var cmd = host + " " + configureNightlyJs + " " + packageJson + " " + programTs;
+    var cmd = host + " " + configureNightlyJs + " " + packageJson + " " + versionFile;
     console.log(cmd);
     exec(cmd);
 }, { async: true });
@@ -637,7 +638,7 @@ task("importDefinitelyTypedTests", [importDefinitelyTypedTestsJs], function () {
 
 // Local target to build the compiler and services
 var tscFile = path.join(builtLocalDirectory, compilerFilename);
-compileFile(tscFile, compilerSources, [builtLocalDirectory, copyright].concat(compilerSources), [copyright], /*useBuiltCompiler:*/ false);
+compileFile(tscFile, compilerSources, [builtLocalDirectory, copyright].concat(compilerSources), [copyright], /*useBuiltCompiler:*/ false, { noMapRoot: true });
 
 var servicesFile = path.join(builtLocalDirectory, "typescriptServices.js");
 var servicesFileInBrowserTest = path.join(builtLocalDirectory, "typescriptServicesInBrowserTest.js");
@@ -927,7 +928,7 @@ function runConsoleTests(defaultReporter, runInParallel) {
     }
 
     if (tests && tests.toLocaleLowerCase() === "rwc") {
-        testTimeout = 400000;
+        testTimeout = 800000;
     }
 
     colors = process.env.colors || process.env.color;
@@ -1083,12 +1084,10 @@ task("tests-debug", ["setDebugMode", "tests"]);
 // Makes the test results the new baseline
 desc("Makes the most recent test results the new baseline, overwriting the old baseline");
 task("baseline-accept", function () {
-    acceptBaseline("");
+    acceptBaseline(localBaseline, refBaseline);
 });
 
-function acceptBaseline(containerFolder) {
-    var sourceFolder = path.join(localBaseline, containerFolder);
-    var targetFolder = path.join(refBaseline, containerFolder);
+function acceptBaseline(sourceFolder, targetFolder) {
     console.log('Accept baselines from ' + sourceFolder + ' to ' + targetFolder);
     var files = fs.readdirSync(sourceFolder);
     var deleteEnding = '.delete';
@@ -1112,12 +1111,12 @@ function acceptBaseline(containerFolder) {
 
 desc("Makes the most recent rwc test results the new baseline, overwriting the old baseline");
 task("baseline-accept-rwc", function () {
-    acceptBaseline("rwc");
+    acceptBaseline(localRwcBaseline, refRwcBaseline);
 });
 
 desc("Makes the most recent test262 test results the new baseline, overwriting the old baseline");
 task("baseline-accept-test262", function () {
-    acceptBaseline("test262");
+    acceptBaseline(localTest262Baseline, refTest262Baseline);
 });
 
 
@@ -1180,7 +1179,6 @@ task("update-sublime", ["local", serverFile], function () {
 var tslintRuleDir = "scripts/tslint";
 var tslintRules = [
     "nextLineRule",
-    "preferConstRule",
     "booleanTriviaRule",
     "typeOperatorSpacingRule",
     "noInOperatorRule",

issue_template.md

@@ -2,7 +2,7 @@
 <!-- QUESTIONS: This is not a general support forum! Ask Qs at http://stackoverflow.com/questions/tagged/typescript -->
 <!-- SUGGESTIONS: See https://github.com/Microsoft/TypeScript-wiki/blob/master/Writing-Good-Design-Proposals.md -->
 
-**TypeScript Version:**  2.0.3 / nightly (2.1.0-dev.201xxxxx)
+**TypeScript Version:**  2.1.1 / nightly (2.2.0-dev.201xxxxx)
 
 **Code**
 
@@ -13,4 +13,4 @@
 
 **Expected behavior:**
 
-**Actual behavior:** 
+**Actual behavior:**

lib/.gitattributes

@@ -0,0 +1 @@
+* text eol=lf

lib/README.md

@@ -1,5 +1,5 @@
-# Read This!
-
-**These files are not meant to be edited by hand.**
-If you need to make modifications, the respective files should be changed within the repository's top-level `src` directory.
-Running `jake LKG` will then appropriately update the files in this directory.
+# Read This!
+
+**These files are not meant to be edited by hand.**
+If you need to make modifications, the respective files should be changed within the repository's top-level `src` directory.
+Running `jake LKG` will then appropriately update the files in this directory.

lib/cancellationToken.js

@@ -1,18 +1,18 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
+
 "use strict";
 var fs = require("fs");
 function createCancellationToken(args) {
@@ -39,5 +39,3 @@ function createCancellationToken(args) {
     };
 }
 module.exports = createCancellationToken;
-
-//# sourceMappingURL=cancellationToken.js.map

lib/lib.dom.iterable.d.ts

@@ -1,33 +1,33 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/// <reference path="lib.dom.d.ts" />
-
-interface DOMTokenList {
-    [Symbol.iterator](): IterableIterator<string>;
-}
-
-interface NodeList {
-    [Symbol.iterator](): IterableIterator<Node>
-}
-
-interface NodeListOf<TNode extends Node> {
-    [Symbol.iterator](): IterableIterator<TNode>
-}
+/// <reference path="lib.dom.d.ts" />
+
+interface DOMTokenList {
+    [Symbol.iterator](): IterableIterator<string>;
+}
+
+interface NodeList {
+    [Symbol.iterator](): IterableIterator<Node>
+}
+
+interface NodeListOf<TNode extends Node> {
+    [Symbol.iterator](): IterableIterator<TNode>
+}

lib/lib.es2015.collection.d.ts

@@ -1,92 +1,92 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-interface Map<K, V> {
-    clear(): void;
-    delete(key: K): boolean;
-    forEach(callbackfn: (value: V, key: K, map: Map<K, V>) => void, thisArg?: any): void;
-    get(key: K): V | undefined;
-    has(key: K): boolean;
-    set(key: K, value?: V): this;
-    readonly size: number;
-}
-
-interface MapConstructor {
-    new (): Map<any, any>;
-    new <K, V>(entries?: [K, V][]): Map<K, V>;
-    readonly prototype: Map<any, any>;
-}
-declare var Map: MapConstructor;
-
-interface ReadonlyMap<K, V> {
-    forEach(callbackfn: (value: V, key: K, map: ReadonlyMap<K, V>) => void, thisArg?: any): void;
-    get(key: K): V|undefined;
-    has(key: K): boolean;
-    readonly size: number;
-}
-
-interface WeakMap<K, V> {
-    delete(key: K): boolean;
-    get(key: K): V | undefined;
-    has(key: K): boolean;
-    set(key: K, value?: V): this;
-}
-
-interface WeakMapConstructor {
-    new (): WeakMap<any, any>;
-    new <K, V>(entries?: [K, V][]): WeakMap<K, V>;
-    readonly prototype: WeakMap<any, any>;
-}
-declare var WeakMap: WeakMapConstructor;
-
-interface Set<T> {
-    add(value: T): this;
-    clear(): void;
-    delete(value: T): boolean;
-    forEach(callbackfn: (value: T, value2: T, set: Set<T>) => void, thisArg?: any): void;
-    has(value: T): boolean;
-    readonly size: number;
-}
-
-interface SetConstructor {
-    new (): Set<any>;
-    new <T>(values?: T[]): Set<T>;
-    readonly prototype: Set<any>;
-}
-declare var Set: SetConstructor;
-
-interface ReadonlySet<T> {
-    forEach(callbackfn: (value: T, value2: T, set: ReadonlySet<T>) => void, thisArg?: any): void;
-    has(value: T): boolean;
-    readonly size: number;
-}
-
-interface WeakSet<T> {
-    add(value: T): this;
-    delete(value: T): boolean;
-    has(value: T): boolean;
-}
-
-interface WeakSetConstructor {
-    new (): WeakSet<any>;
-    new <T>(values?: T[]): WeakSet<T>;
-    readonly prototype: WeakSet<any>;
-}
-declare var WeakSet: WeakSetConstructor;
+interface Map<K, V> {
+    clear(): void;
+    delete(key: K): boolean;
+    forEach(callbackfn: (value: V, key: K, map: Map<K, V>) => void, thisArg?: any): void;
+    get(key: K): V | undefined;
+    has(key: K): boolean;
+    set(key: K, value?: V): this;
+    readonly size: number;
+}
+
+interface MapConstructor {
+    new (): Map<any, any>;
+    new <K, V>(entries?: [K, V][]): Map<K, V>;
+    readonly prototype: Map<any, any>;
+}
+declare var Map: MapConstructor;
+
+interface ReadonlyMap<K, V> {
+    forEach(callbackfn: (value: V, key: K, map: ReadonlyMap<K, V>) => void, thisArg?: any): void;
+    get(key: K): V|undefined;
+    has(key: K): boolean;
+    readonly size: number;
+}
+
+interface WeakMap<K, V> {
+    delete(key: K): boolean;
+    get(key: K): V | undefined;
+    has(key: K): boolean;
+    set(key: K, value?: V): this;
+}
+
+interface WeakMapConstructor {
+    new (): WeakMap<any, any>;
+    new <K, V>(entries?: [K, V][]): WeakMap<K, V>;
+    readonly prototype: WeakMap<any, any>;
+}
+declare var WeakMap: WeakMapConstructor;
+
+interface Set<T> {
+    add(value: T): this;
+    clear(): void;
+    delete(value: T): boolean;
+    forEach(callbackfn: (value: T, value2: T, set: Set<T>) => void, thisArg?: any): void;
+    has(value: T): boolean;
+    readonly size: number;
+}
+
+interface SetConstructor {
+    new (): Set<any>;
+    new <T>(values?: T[]): Set<T>;
+    readonly prototype: Set<any>;
+}
+declare var Set: SetConstructor;
+
+interface ReadonlySet<T> {
+    forEach(callbackfn: (value: T, value2: T, set: ReadonlySet<T>) => void, thisArg?: any): void;
+    has(value: T): boolean;
+    readonly size: number;
+}
+
+interface WeakSet<T> {
+    add(value: T): this;
+    delete(value: T): boolean;
+    has(value: T): boolean;
+}
+
+interface WeakSetConstructor {
+    new (): WeakSet<any>;
+    new <T>(values?: T[]): WeakSet<T>;
+    readonly prototype: WeakSet<any>;
+}
+declare var WeakSet: WeakSetConstructor;

lib/lib.es2015.d.ts

@@ -1,30 +1,30 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/// <reference path="lib.es2015.core.d.ts" />
-/// <reference path="lib.es2015.collection.d.ts" />
-/// <reference path="lib.es2015.generator.d.ts" />
-/// <reference path="lib.es2015.iterable.d.ts" />
-/// <reference path="lib.es2015.promise.d.ts" />
-/// <reference path="lib.es2015.proxy.d.ts" />
-/// <reference path="lib.es2015.reflect.d.ts" />
-/// <reference path="lib.es2015.symbol.d.ts" />
-/// <reference path="lib.es2015.symbol.wellknown.d.ts" />
+/// <reference path="lib.es2015.core.d.ts" />
+/// <reference path="lib.es2015.collection.d.ts" />
+/// <reference path="lib.es2015.generator.d.ts" />
+/// <reference path="lib.es2015.iterable.d.ts" />
+/// <reference path="lib.es2015.promise.d.ts" />
+/// <reference path="lib.es2015.proxy.d.ts" />
+/// <reference path="lib.es2015.reflect.d.ts" />
+/// <reference path="lib.es2015.symbol.d.ts" />
+/// <reference path="lib.es2015.symbol.wellknown.d.ts" />
 /// <reference path="lib.es5.d.ts" />

lib/lib.es2015.generator.d.ts

@@ -1,32 +1,32 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-interface GeneratorFunction extends Function { }
-
-interface GeneratorFunctionConstructor {
-    /**
-      * Creates a new Generator function.
-      * @param args A list of arguments the function accepts.
-      */
-    new (...args: string[]): GeneratorFunction;
-    (...args: string[]): GeneratorFunction;
-    readonly prototype: GeneratorFunction;
-}
-declare var GeneratorFunction: GeneratorFunctionConstructor;
+interface GeneratorFunction extends Function { }
+
+interface GeneratorFunctionConstructor {
+    /**
+      * Creates a new Generator function.
+      * @param args A list of arguments the function accepts.
+      */
+    new (...args: string[]): GeneratorFunction;
+    (...args: string[]): GeneratorFunction;
+    readonly prototype: GeneratorFunction;
+}
+declare var GeneratorFunction: GeneratorFunctionConstructor;

lib/lib.es2015.iterable.d.ts

@@ -1,465 +1,465 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/// <reference path="lib.es2015.symbol.d.ts" />
-
-interface SymbolConstructor {
-    /** 
-      * A method that returns the default iterator for an object. Called by the semantics of the 
-      * for-of statement.
-      */
-    readonly iterator: symbol;
-}
-
-interface IteratorResult<T> {
-    done: boolean;
-    value: T;
-}
-
-interface Iterator<T> {
-    next(value?: any): IteratorResult<T>;
-    return?(value?: any): IteratorResult<T>;
-    throw?(e?: any): IteratorResult<T>;
-}
-
-interface Iterable<T> {
-    [Symbol.iterator](): Iterator<T>;
-}
-
-interface IterableIterator<T> extends Iterator<T> {
-    [Symbol.iterator](): IterableIterator<T>;
-}
-
-interface Array<T> {
-    /** Iterator */
-    [Symbol.iterator](): IterableIterator<T>;
-
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, T]>;
-
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<T>;
-}
-
-interface ArrayConstructor {
-    /**
-      * Creates an array from an iterable object.
-      * @param iterable An iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from<T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): Array<U>;
-    
-    /**
-      * Creates an array from an iterable object.
-      * @param iterable An iterable object to convert to an array.
-      */
-    from<T>(iterable: Iterable<T>): Array<T>;
-}
-
-interface ReadonlyArray<T> {
-    /** Iterator */
-    [Symbol.iterator](): IterableIterator<T>;
-
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, T]>;
-
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<T>;
-}
-
-interface IArguments {
-    /** Iterator */
-    [Symbol.iterator](): IterableIterator<any>;
-}
-
-interface Map<K, V> {
-    [Symbol.iterator](): IterableIterator<[K,V]>;
-    entries(): IterableIterator<[K, V]>;
-    keys(): IterableIterator<K>;
-    values(): IterableIterator<V>;
-}
-
-interface MapConstructor {
-    new <K, V>(iterable: Iterable<[K, V]>): Map<K, V>;
-}
-
-interface WeakMap<K, V> { }
-
-interface WeakMapConstructor {
-    new <K, V>(iterable: Iterable<[K, V]>): WeakMap<K, V>;
-}
-
-interface Set<T> {
-    [Symbol.iterator](): IterableIterator<T>;
-    entries(): IterableIterator<[T, T]>;
-    keys(): IterableIterator<T>;
-    values(): IterableIterator<T>;
-}
-
-interface SetConstructor {
-    new <T>(iterable: Iterable<T>): Set<T>;
-}
-
-interface WeakSet<T> { }
-
-interface WeakSetConstructor {
-    new <T>(iterable: Iterable<T>): WeakSet<T>;
-}
-
-interface Promise<T> { }
-
-interface PromiseConstructor {
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises 
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<TAll>(values: Iterable<TAll | PromiseLike<TAll>>): Promise<TAll[]>;
-    
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved 
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T>(values: Iterable<T | PromiseLike<T>>): Promise<T>;
-}
-
-declare namespace Reflect {
-    function enumerate(target: any): IterableIterator<any>;
-}
-
-interface String {
-    /** Iterator */
-    [Symbol.iterator](): IterableIterator<string>;
-}
-
-/**
-  * A typed array of 8-bit integer values. The contents are initialized to 0. If the requested 
-  * number of bytes could not be allocated an exception is raised.
-  */
-interface Int8Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Int8ArrayConstructor {
-    new (elements: Iterable<number>): Int8Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Int8Array;
-}
-
-/**
-  * A typed array of 8-bit unsigned integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint8Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Uint8ArrayConstructor {
-    new (elements: Iterable<number>): Uint8Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint8Array;
-}
-
-/**
-  * A typed array of 8-bit unsigned integer (clamped) values. The contents are initialized to 0. 
-  * If the requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint8ClampedArray {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Uint8ClampedArrayConstructor {
-    new (elements: Iterable<number>): Uint8ClampedArray;
-
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint8ClampedArray;
-}
-
-/**
-  * A typed array of 16-bit signed integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Int16Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Int16ArrayConstructor {
-    new (elements: Iterable<number>): Int16Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Int16Array;
-}
-
-/**
-  * A typed array of 16-bit unsigned integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint16Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Uint16ArrayConstructor {
-    new (elements: Iterable<number>): Uint16Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint16Array;
-}
-
-/**
-  * A typed array of 32-bit signed integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Int32Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Int32ArrayConstructor {
-    new (elements: Iterable<number>): Int32Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Int32Array;
-}
-
-/**
-  * A typed array of 32-bit unsigned integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint32Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Uint32ArrayConstructor {
-    new (elements: Iterable<number>): Uint32Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint32Array;
-}
-
-/**
-  * A typed array of 32-bit float values. The contents are initialized to 0. If the requested number
-  * of bytes could not be allocated an exception is raised.
-  */
-interface Float32Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Float32ArrayConstructor {
-    new (elements: Iterable<number>): Float32Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Float32Array;
-}
-
-/**
-  * A typed array of 64-bit float values. The contents are initialized to 0. If the requested 
-  * number of bytes could not be allocated an exception is raised.
-  */
-interface Float64Array {
-    [Symbol.iterator](): IterableIterator<number>;
-    /** 
-      * Returns an array of key, value pairs for every entry in the array
-      */
-    entries(): IterableIterator<[number, number]>;
-    /** 
-      * Returns an list of keys in the array
-      */
-    keys(): IterableIterator<number>;
-    /** 
-      * Returns an list of values in the array
-      */
-    values(): IterableIterator<number>;
-}
-
-interface Float64ArrayConstructor {
-    new (elements: Iterable<number>): Float64Array;
-
-    /**
-      * Creates an array from an array-like or iterable object.
-      * @param arrayLike An array-like or iterable object to convert to an array.
-      * @param mapfn A mapping function to call on every element of the array.
-      * @param thisArg Value of 'this' used to invoke the mapfn.
-      */
-    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Float64Array;
+/// <reference path="lib.es2015.symbol.d.ts" />
+
+interface SymbolConstructor {
+    /** 
+      * A method that returns the default iterator for an object. Called by the semantics of the 
+      * for-of statement.
+      */
+    readonly iterator: symbol;
+}
+
+interface IteratorResult<T> {
+    done: boolean;
+    value: T;
+}
+
+interface Iterator<T> {
+    next(value?: any): IteratorResult<T>;
+    return?(value?: any): IteratorResult<T>;
+    throw?(e?: any): IteratorResult<T>;
+}
+
+interface Iterable<T> {
+    [Symbol.iterator](): Iterator<T>;
+}
+
+interface IterableIterator<T> extends Iterator<T> {
+    [Symbol.iterator](): IterableIterator<T>;
+}
+
+interface Array<T> {
+    /** Iterator */
+    [Symbol.iterator](): IterableIterator<T>;
+
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, T]>;
+
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<T>;
+}
+
+interface ArrayConstructor {
+    /**
+      * Creates an array from an iterable object.
+      * @param iterable An iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from<T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): Array<U>;
+    
+    /**
+      * Creates an array from an iterable object.
+      * @param iterable An iterable object to convert to an array.
+      */
+    from<T>(iterable: Iterable<T>): Array<T>;
+}
+
+interface ReadonlyArray<T> {
+    /** Iterator */
+    [Symbol.iterator](): IterableIterator<T>;
+
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, T]>;
+
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<T>;
+}
+
+interface IArguments {
+    /** Iterator */
+    [Symbol.iterator](): IterableIterator<any>;
+}
+
+interface Map<K, V> {
+    [Symbol.iterator](): IterableIterator<[K,V]>;
+    entries(): IterableIterator<[K, V]>;
+    keys(): IterableIterator<K>;
+    values(): IterableIterator<V>;
+}
+
+interface MapConstructor {
+    new <K, V>(iterable: Iterable<[K, V]>): Map<K, V>;
+}
+
+interface WeakMap<K, V> { }
+
+interface WeakMapConstructor {
+    new <K, V>(iterable: Iterable<[K, V]>): WeakMap<K, V>;
+}
+
+interface Set<T> {
+    [Symbol.iterator](): IterableIterator<T>;
+    entries(): IterableIterator<[T, T]>;
+    keys(): IterableIterator<T>;
+    values(): IterableIterator<T>;
+}
+
+interface SetConstructor {
+    new <T>(iterable: Iterable<T>): Set<T>;
+}
+
+interface WeakSet<T> { }
+
+interface WeakSetConstructor {
+    new <T>(iterable: Iterable<T>): WeakSet<T>;
+}
+
+interface Promise<T> { }
+
+interface PromiseConstructor {
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises 
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<TAll>(values: Iterable<TAll | PromiseLike<TAll>>): Promise<TAll[]>;
+    
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved 
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T>(values: Iterable<T | PromiseLike<T>>): Promise<T>;
+}
+
+declare namespace Reflect {
+    function enumerate(target: any): IterableIterator<any>;
+}
+
+interface String {
+    /** Iterator */
+    [Symbol.iterator](): IterableIterator<string>;
+}
+
+/**
+  * A typed array of 8-bit integer values. The contents are initialized to 0. If the requested 
+  * number of bytes could not be allocated an exception is raised.
+  */
+interface Int8Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Int8ArrayConstructor {
+    new (elements: Iterable<number>): Int8Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Int8Array;
+}
+
+/**
+  * A typed array of 8-bit unsigned integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint8Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Uint8ArrayConstructor {
+    new (elements: Iterable<number>): Uint8Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint8Array;
+}
+
+/**
+  * A typed array of 8-bit unsigned integer (clamped) values. The contents are initialized to 0. 
+  * If the requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint8ClampedArray {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Uint8ClampedArrayConstructor {
+    new (elements: Iterable<number>): Uint8ClampedArray;
+
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint8ClampedArray;
+}
+
+/**
+  * A typed array of 16-bit signed integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Int16Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Int16ArrayConstructor {
+    new (elements: Iterable<number>): Int16Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Int16Array;
+}
+
+/**
+  * A typed array of 16-bit unsigned integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint16Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Uint16ArrayConstructor {
+    new (elements: Iterable<number>): Uint16Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint16Array;
+}
+
+/**
+  * A typed array of 32-bit signed integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Int32Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Int32ArrayConstructor {
+    new (elements: Iterable<number>): Int32Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Int32Array;
+}
+
+/**
+  * A typed array of 32-bit unsigned integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint32Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Uint32ArrayConstructor {
+    new (elements: Iterable<number>): Uint32Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Uint32Array;
+}
+
+/**
+  * A typed array of 32-bit float values. The contents are initialized to 0. If the requested number
+  * of bytes could not be allocated an exception is raised.
+  */
+interface Float32Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Float32ArrayConstructor {
+    new (elements: Iterable<number>): Float32Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Float32Array;
+}
+
+/**
+  * A typed array of 64-bit float values. The contents are initialized to 0. If the requested 
+  * number of bytes could not be allocated an exception is raised.
+  */
+interface Float64Array {
+    [Symbol.iterator](): IterableIterator<number>;
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, number]>;
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<number>;
+}
+
+interface Float64ArrayConstructor {
+    new (elements: Iterable<number>): Float64Array;
+
+    /**
+      * Creates an array from an array-like or iterable object.
+      * @param arrayLike An array-like or iterable object to convert to an array.
+      * @param mapfn A mapping function to call on every element of the array.
+      * @param thisArg Value of 'this' used to invoke the mapfn.
+      */
+    from(arrayLike: Iterable<number>, mapfn?: (v: number, k: number) => number, thisArg?: any): Float64Array;
 }

lib/lib.es2015.promise.d.ts

@@ -1,274 +1,274 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/**
- * Represents the completion of an asynchronous operation
- */
-interface Promise<T> {
-    /**
-     * Attaches callbacks for the resolution and/or rejection of the Promise.
-     * @param onfulfilled The callback to execute when the Promise is resolved.
-     * @param onrejected The callback to execute when the Promise is rejected.
-     * @returns A Promise for the completion of which ever callback is executed.
-     */
-    then(onfulfilled?: ((value: T) => T | PromiseLike<T>) | undefined | null, onrejected?: ((reason: any) => T | PromiseLike<T>) | undefined | null): Promise<T>;
-
-    /**
-     * Attaches callbacks for the resolution and/or rejection of the Promise.
-     * @param onfulfilled The callback to execute when the Promise is resolved.
-     * @param onrejected The callback to execute when the Promise is rejected.
-     * @returns A Promise for the completion of which ever callback is executed.
-     */
-    then<TResult>(onfulfilled: ((value: T) => T | PromiseLike<T>) | undefined | null, onrejected: (reason: any) => TResult | PromiseLike<TResult>): Promise<T | TResult>;
-
-    /**
-     * Attaches callbacks for the resolution and/or rejection of the Promise.
-     * @param onfulfilled The callback to execute when the Promise is resolved.
-     * @param onrejected The callback to execute when the Promise is rejected.
-     * @returns A Promise for the completion of which ever callback is executed.
-     */
-    then<TResult>(onfulfilled: (value: T) => TResult | PromiseLike<TResult>, onrejected?: ((reason: any) => TResult | PromiseLike<TResult>) | undefined | null): Promise<TResult>;
-
-    /**
-     * Attaches callbacks for the resolution and/or rejection of the Promise.
-     * @param onfulfilled The callback to execute when the Promise is resolved.
-     * @param onrejected The callback to execute when the Promise is rejected.
-     * @returns A Promise for the completion of which ever callback is executed.
-     */
-    then<TResult1, TResult2>(onfulfilled: (value: T) => TResult1 | PromiseLike<TResult1>, onrejected: (reason: any) => TResult2 | PromiseLike<TResult2>): Promise<TResult1 | TResult2>;
-
-    /**
-     * Attaches a callback for only the rejection of the Promise.
-     * @param onrejected The callback to execute when the Promise is rejected.
-     * @returns A Promise for the completion of the callback.
-     */
-    catch(onrejected?: ((reason: any) => T | PromiseLike<T>) | undefined | null): Promise<T>;
-
-    /**
-     * Attaches a callback for only the rejection of the Promise.
-     * @param onrejected The callback to execute when the Promise is rejected.
-     * @returns A Promise for the completion of the callback.
-     */
-    catch<TResult>(onrejected: (reason: any) => TResult | PromiseLike<TResult>): Promise<T | TResult>;
-}
-
-interface PromiseConstructor {
-    /**
-      * A reference to the prototype.
-      */
-    readonly prototype: Promise<any>;
-
-    /**
-     * Creates a new Promise.
-     * @param executor A callback used to initialize the promise. This callback is passed two arguments:
-     * a resolve callback used resolve the promise with a value or the result of another promise,
-     * and a reject callback used to reject the promise with a provided reason or error.
-     */
-    new <T>(executor: (resolve: (value?: T | PromiseLike<T>) => void, reject: (reason?: any) => void) => void): Promise<T>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>, T10 | PromiseLike<T10>]): Promise<[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3, T4, T5, T6, T7, T8, T9>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>]): Promise<[T1, T2, T3, T4, T5, T6, T7, T8, T9]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3, T4, T5, T6, T7, T8>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>]): Promise<[T1, T2, T3, T4, T5, T6, T7, T8]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3, T4, T5, T6, T7>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>]): Promise<[T1, T2, T3, T4, T5, T6, T7]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3, T4, T5, T6>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>]): Promise<[T1, T2, T3, T4, T5, T6]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3, T4, T5>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>]): Promise<[T1, T2, T3, T4, T5]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3, T4>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>]): Promise<[T1, T2, T3, T4]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2, T3>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>]): Promise<[T1, T2, T3]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T1, T2>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>]): Promise<[T1, T2]>;
-
-    /**
-     * Creates a Promise that is resolved with an array of results when all of the provided Promises
-     * resolve, or rejected when any Promise is rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    all<T>(values: (T | PromiseLike<T>)[]): Promise<T[]>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>, T10 | PromiseLike<T10>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 | T9 | T10>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3, T4, T5, T6, T7, T8, T9>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 | T9>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3, T4, T5, T6, T7, T8>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3, T4, T5, T6, T7>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3, T4, T5, T6>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>]): Promise<T1 | T2 | T3 | T4 | T5 | T6>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3, T4, T5>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>]): Promise<T1 | T2 | T3 | T4 | T5>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3, T4>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>]): Promise<T1 | T2 | T3 | T4>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2, T3>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>]): Promise<T1 | T2 | T3>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T1, T2>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>]): Promise<T1 | T2>;
-
-    /**
-     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
-     * or rejected.
-     * @param values An array of Promises.
-     * @returns A new Promise.
-     */
-    race<T>(values: (T | PromiseLike<T>)[]): Promise<T>;
-
-    /**
-     * Creates a new rejected promise for the provided reason.
-     * @param reason The reason the promise was rejected.
-     * @returns A new rejected Promise.
-     */
-    reject(reason: any): Promise<never>;
-
-    /**
-     * Creates a new rejected promise for the provided reason.
-     * @param reason The reason the promise was rejected.
-     * @returns A new rejected Promise.
-     */
-    reject<T>(reason: any): Promise<T>;
-
-    /**
-      * Creates a new resolved promise for the provided value.
-      * @param value A promise.
-      * @returns A promise whose internal state matches the provided promise.
-      */
-    resolve<T>(value: T | PromiseLike<T>): Promise<T>;
-
-    /**
-     * Creates a new resolved promise .
-     * @returns A resolved promise.
-     */
-    resolve(): Promise<void>;
-}
-
+/**
+ * Represents the completion of an asynchronous operation
+ */
+interface Promise<T> {
+    /**
+     * Attaches callbacks for the resolution and/or rejection of the Promise.
+     * @param onfulfilled The callback to execute when the Promise is resolved.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of which ever callback is executed.
+     */
+    then(onfulfilled?: ((value: T) => T | PromiseLike<T>) | undefined | null, onrejected?: ((reason: any) => T | PromiseLike<T>) | undefined | null): Promise<T>;
+
+    /**
+     * Attaches callbacks for the resolution and/or rejection of the Promise.
+     * @param onfulfilled The callback to execute when the Promise is resolved.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of which ever callback is executed.
+     */
+    then<TResult>(onfulfilled: ((value: T) => T | PromiseLike<T>) | undefined | null, onrejected: (reason: any) => TResult | PromiseLike<TResult>): Promise<T | TResult>;
+
+    /**
+     * Attaches callbacks for the resolution and/or rejection of the Promise.
+     * @param onfulfilled The callback to execute when the Promise is resolved.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of which ever callback is executed.
+     */
+    then<TResult>(onfulfilled: (value: T) => TResult | PromiseLike<TResult>, onrejected?: ((reason: any) => TResult | PromiseLike<TResult>) | undefined | null): Promise<TResult>;
+
+    /**
+     * Attaches callbacks for the resolution and/or rejection of the Promise.
+     * @param onfulfilled The callback to execute when the Promise is resolved.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of which ever callback is executed.
+     */
+    then<TResult1, TResult2>(onfulfilled: (value: T) => TResult1 | PromiseLike<TResult1>, onrejected: (reason: any) => TResult2 | PromiseLike<TResult2>): Promise<TResult1 | TResult2>;
+
+    /**
+     * Attaches a callback for only the rejection of the Promise.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of the callback.
+     */
+    catch(onrejected?: ((reason: any) => T | PromiseLike<T>) | undefined | null): Promise<T>;
+
+    /**
+     * Attaches a callback for only the rejection of the Promise.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of the callback.
+     */
+    catch<TResult>(onrejected: (reason: any) => TResult | PromiseLike<TResult>): Promise<T | TResult>;
+}
+
+interface PromiseConstructor {
+    /**
+      * A reference to the prototype.
+      */
+    readonly prototype: Promise<any>;
+
+    /**
+     * Creates a new Promise.
+     * @param executor A callback used to initialize the promise. This callback is passed two arguments:
+     * a resolve callback used resolve the promise with a value or the result of another promise,
+     * and a reject callback used to reject the promise with a provided reason or error.
+     */
+    new <T>(executor: (resolve: (value?: T | PromiseLike<T>) => void, reject: (reason?: any) => void) => void): Promise<T>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>, T10 | PromiseLike<T10>]): Promise<[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3, T4, T5, T6, T7, T8, T9>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>]): Promise<[T1, T2, T3, T4, T5, T6, T7, T8, T9]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3, T4, T5, T6, T7, T8>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>]): Promise<[T1, T2, T3, T4, T5, T6, T7, T8]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3, T4, T5, T6, T7>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>]): Promise<[T1, T2, T3, T4, T5, T6, T7]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3, T4, T5, T6>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>]): Promise<[T1, T2, T3, T4, T5, T6]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3, T4, T5>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>, T5 | PromiseLike<T5>]): Promise<[T1, T2, T3, T4, T5]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3, T4>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike <T4>]): Promise<[T1, T2, T3, T4]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2, T3>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>]): Promise<[T1, T2, T3]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T1, T2>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>]): Promise<[T1, T2]>;
+
+    /**
+     * Creates a Promise that is resolved with an array of results when all of the provided Promises
+     * resolve, or rejected when any Promise is rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    all<T>(values: (T | PromiseLike<T>)[]): Promise<T[]>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>, T10 | PromiseLike<T10>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 | T9 | T10>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3, T4, T5, T6, T7, T8, T9>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>, T9 | PromiseLike<T9>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 | T9>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3, T4, T5, T6, T7, T8>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>, T8 | PromiseLike<T8>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3, T4, T5, T6, T7>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>, T7 | PromiseLike<T7>]): Promise<T1 | T2 | T3 | T4 | T5 | T6 | T7>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3, T4, T5, T6>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>, T6 | PromiseLike<T6>]): Promise<T1 | T2 | T3 | T4 | T5 | T6>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3, T4, T5>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>, T5 | PromiseLike<T5>]): Promise<T1 | T2 | T3 | T4 | T5>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3, T4>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>, T4 | PromiseLike<T4>]): Promise<T1 | T2 | T3 | T4>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2, T3>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>, T3 | PromiseLike<T3>]): Promise<T1 | T2 | T3>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T1, T2>(values: [T1 | PromiseLike<T1>, T2 | PromiseLike<T2>]): Promise<T1 | T2>;
+
+    /**
+     * Creates a Promise that is resolved or rejected when any of the provided Promises are resolved
+     * or rejected.
+     * @param values An array of Promises.
+     * @returns A new Promise.
+     */
+    race<T>(values: (T | PromiseLike<T>)[]): Promise<T>;
+
+    /**
+     * Creates a new rejected promise for the provided reason.
+     * @param reason The reason the promise was rejected.
+     * @returns A new rejected Promise.
+     */
+    reject(reason: any): Promise<never>;
+
+    /**
+     * Creates a new rejected promise for the provided reason.
+     * @param reason The reason the promise was rejected.
+     * @returns A new rejected Promise.
+     */
+    reject<T>(reason: any): Promise<T>;
+
+    /**
+      * Creates a new resolved promise for the provided value.
+      * @param value A promise.
+      * @returns A promise whose internal state matches the provided promise.
+      */
+    resolve<T>(value: T | PromiseLike<T>): Promise<T>;
+
+    /**
+     * Creates a new resolved promise .
+     * @returns A resolved promise.
+     */
+    resolve(): Promise<void>;
+}
+
 declare var Promise: PromiseConstructor;

lib/lib.es2015.proxy.d.ts

@@ -1,42 +1,42 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-interface ProxyHandler<T> {
-    getPrototypeOf? (target: T): any;
-    setPrototypeOf? (target: T, v: any): boolean;
-    isExtensible? (target: T): boolean;
-    preventExtensions? (target: T): boolean;
-    getOwnPropertyDescriptor? (target: T, p: PropertyKey): PropertyDescriptor;
-    has? (target: T, p: PropertyKey): boolean;
-    get? (target: T, p: PropertyKey, receiver: any): any;
-    set? (target: T, p: PropertyKey, value: any, receiver: any): boolean;
-    deleteProperty? (target: T, p: PropertyKey): boolean;
-    defineProperty? (target: T, p: PropertyKey, attributes: PropertyDescriptor): boolean;
-    enumerate? (target: T): PropertyKey[];
-    ownKeys? (target: T): PropertyKey[];
-    apply? (target: T, thisArg: any, argArray?: any): any;
-    construct? (target: T, thisArg: any, argArray?: any): any;
-}
-
-interface ProxyConstructor {
-    revocable<T>(target: T, handler: ProxyHandler<T>): { proxy: T; revoke: () => void; };
-    new <T>(target: T, handler: ProxyHandler<T>): T
-}
-declare var Proxy: ProxyConstructor;
+interface ProxyHandler<T> {
+    getPrototypeOf? (target: T): {} | null;
+    setPrototypeOf? (target: T, v: any): boolean;
+    isExtensible? (target: T): boolean;
+    preventExtensions? (target: T): boolean;
+    getOwnPropertyDescriptor? (target: T, p: PropertyKey): PropertyDescriptor;
+    has? (target: T, p: PropertyKey): boolean;
+    get? (target: T, p: PropertyKey, receiver: any): any;
+    set? (target: T, p: PropertyKey, value: any, receiver: any): boolean;
+    deleteProperty? (target: T, p: PropertyKey): boolean;
+    defineProperty? (target: T, p: PropertyKey, attributes: PropertyDescriptor): boolean;
+    enumerate? (target: T): PropertyKey[];
+    ownKeys? (target: T): PropertyKey[];
+    apply? (target: T, thisArg: any, argArray?: any): any;
+    construct? (target: T, argArray: any, newTarget?: any): {};
+}
+
+interface ProxyConstructor {
+    revocable<T>(target: T, handler: ProxyHandler<T>): { proxy: T; revoke: () => void; };
+    new <T>(target: T, handler: ProxyHandler<T>): T
+}
+declare var Proxy: ProxyConstructor;

lib/lib.es2015.reflect.d.ts

@@ -1,35 +1,35 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-declare namespace Reflect {
-    function apply(target: Function, thisArgument: any, argumentsList: ArrayLike<any>): any;
-    function construct(target: Function, argumentsList: ArrayLike<any>, newTarget?: any): any;
-    function defineProperty(target: any, propertyKey: PropertyKey, attributes: PropertyDescriptor): boolean;
-    function deleteProperty(target: any, propertyKey: PropertyKey): boolean;
-    function get(target: any, propertyKey: PropertyKey, receiver?: any): any;
-    function getOwnPropertyDescriptor(target: any, propertyKey: PropertyKey): PropertyDescriptor;
-    function getPrototypeOf(target: any): any;
-    function has(target: any, propertyKey: PropertyKey): boolean;
-    function isExtensible(target: any): boolean;
-    function ownKeys(target: any): Array<PropertyKey>;
-    function preventExtensions(target: any): boolean;
-    function set(target: any, propertyKey: PropertyKey, value: any, receiver?: any): boolean;
-    function setPrototypeOf(target: any, proto: any): boolean;
+declare namespace Reflect {
+    function apply(target: Function, thisArgument: any, argumentsList: ArrayLike<any>): any;
+    function construct(target: Function, argumentsList: ArrayLike<any>, newTarget?: any): any;
+    function defineProperty(target: any, propertyKey: PropertyKey, attributes: PropertyDescriptor): boolean;
+    function deleteProperty(target: any, propertyKey: PropertyKey): boolean;
+    function get(target: any, propertyKey: PropertyKey, receiver?: any): any;
+    function getOwnPropertyDescriptor(target: any, propertyKey: PropertyKey): PropertyDescriptor;
+    function getPrototypeOf(target: any): any;
+    function has(target: any, propertyKey: PropertyKey): boolean;
+    function isExtensible(target: any): boolean;
+    function ownKeys(target: any): Array<PropertyKey>;
+    function preventExtensions(target: any): boolean;
+    function set(target: any, propertyKey: PropertyKey, value: any, receiver?: any): boolean;
+    function setPrototypeOf(target: any, proto: any): boolean;
 }

lib/lib.es2015.symbol.d.ts

@@ -1,56 +1,56 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-interface Symbol {
-    /** Returns a string representation of an object. */
-    toString(): string;
-
-    /** Returns the primitive value of the specified object. */
-    valueOf(): Object;
-}
-
-interface SymbolConstructor {
-    /** 
-      * A reference to the prototype. 
-      */
-    readonly prototype: Symbol;
-
-    /**
-      * Returns a new unique Symbol value.
-      * @param  description Description of the new Symbol object.
-      */
-    (description?: string|number): symbol;
-
-    /**
-      * Returns a Symbol object from the global symbol registry matching the given key if found. 
-      * Otherwise, returns a new symbol with this key.
-      * @param key key to search for.
-      */
-    for(key: string): symbol;
-
-    /**
-      * Returns a key from the global symbol registry matching the given Symbol if found. 
-      * Otherwise, returns a undefined.
-      * @param sym Symbol to find the key for.
-      */
-    keyFor(sym: symbol): string | undefined;
-}
-
+interface Symbol {
+    /** Returns a string representation of an object. */
+    toString(): string;
+
+    /** Returns the primitive value of the specified object. */
+    valueOf(): Object;
+}
+
+interface SymbolConstructor {
+    /** 
+      * A reference to the prototype. 
+      */
+    readonly prototype: Symbol;
+
+    /**
+      * Returns a new unique Symbol value.
+      * @param  description Description of the new Symbol object.
+      */
+    (description?: string|number): symbol;
+
+    /**
+      * Returns a Symbol object from the global symbol registry matching the given key if found. 
+      * Otherwise, returns a new symbol with this key.
+      * @param key key to search for.
+      */
+    for(key: string): symbol;
+
+    /**
+      * Returns a key from the global symbol registry matching the given Symbol if found. 
+      * Otherwise, returns a undefined.
+      * @param sym Symbol to find the key for.
+      */
+    keyFor(sym: symbol): string | undefined;
+}
+
 declare var Symbol: SymbolConstructor;

lib/lib.es2015.symbol.wellknown.d.ts

@@ -1,347 +1,347 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/// <reference path="lib.es2015.symbol.d.ts" />
-
-interface SymbolConstructor {
-    /** 
-      * A method that determines if a constructor object recognizes an object as one of the 
-      * constructor’s instances. Called by the semantics of the instanceof operator. 
-      */
-    readonly hasInstance: symbol;
-
-    /** 
-      * A Boolean value that if true indicates that an object should flatten to its array elements
-      * by Array.prototype.concat.
-      */
-    readonly isConcatSpreadable: symbol;
-
-    /**
-      * A regular expression method that matches the regular expression against a string. Called 
-      * by the String.prototype.match method. 
-      */
-    readonly match: symbol;
-
-    /** 
-      * A regular expression method that replaces matched substrings of a string. Called by the 
-      * String.prototype.replace method.
-      */
-    readonly replace: symbol;
-
-    /**
-      * A regular expression method that returns the index within a string that matches the 
-      * regular expression. Called by the String.prototype.search method.
-      */
-    readonly search: symbol;
-
-    /** 
-      * A function valued property that is the constructor function that is used to create 
-      * derived objects.
-      */
-    readonly species: symbol;
-
-    /**
-      * A regular expression method that splits a string at the indices that match the regular 
-      * expression. Called by the String.prototype.split method.
-      */
-    readonly split: symbol;
-
-    /** 
-      * A method that converts an object to a corresponding primitive value.
-      * Called by the ToPrimitive abstract operation.
-      */
-    readonly toPrimitive: symbol;
-
-    /** 
-      * A String value that is used in the creation of the default string description of an object.
-      * Called by the built-in method Object.prototype.toString.
-      */
-    readonly toStringTag: symbol;
-
-    /**
-      * An Object whose own property names are property names that are excluded from the 'with'
-      * environment bindings of the associated objects.
-      */
-    readonly unscopables: symbol;
-}
-
-interface Symbol {
-    readonly [Symbol.toStringTag]: "Symbol";
-}
-
-interface Array<T> {
-    /**
-     * Returns an object whose properties have the value 'true'
-     * when they will be absent when used in a 'with' statement.
-     */
-    [Symbol.unscopables](): {
-        copyWithin: boolean;
-        entries: boolean;
-        fill: boolean;
-        find: boolean;
-        findIndex: boolean;
-        keys: boolean;
-        values: boolean;
-    };
-}
-
-interface Date {
-    /**
-     * Converts a Date object to a string.
-     */
-    [Symbol.toPrimitive](hint: "default"): string;
-    /**
-     * Converts a Date object to a string.
-     */
-    [Symbol.toPrimitive](hint: "string"): string;
-    /**
-     * Converts a Date object to a number.
-     */
-    [Symbol.toPrimitive](hint: "number"): number;
-    /**
-     * Converts a Date object to a string or number.
-     *
-     * @param hint The strings "number", "string", or "default" to specify what primitive to return.
-     *
-     * @throws {TypeError} If 'hint' was given something other than "number", "string", or "default".
-     * @returns A number if 'hint' was "number", a string if 'hint' was "string" or "default".
-     */
-    [Symbol.toPrimitive](hint: string): string | number;
-}
-
-interface Map<K, V> {
-    readonly [Symbol.toStringTag]: "Map";
-}
-
-interface WeakMap<K, V>{
-    readonly [Symbol.toStringTag]: "WeakMap";
-}
-
-interface Set<T> {
-    readonly [Symbol.toStringTag]: "Set";
-}
-
-interface WeakSet<T> {
-    readonly [Symbol.toStringTag]: "WeakSet";
-}
-
-interface JSON {
-    readonly [Symbol.toStringTag]: "JSON";
-}
-
-interface Function {
-    /**
-     * Determines whether the given value inherits from this function if this function was used
-     * as a constructor function.
-     *
-     * A constructor function can control which objects are recognized as its instances by
-     * 'instanceof' by overriding this method.
-     */
-    [Symbol.hasInstance](value: any): boolean;
-}
-
-interface GeneratorFunction extends Function {
-    readonly [Symbol.toStringTag]: "GeneratorFunction";
-}
-
-interface Math {
-    readonly [Symbol.toStringTag]: "Math";
-}
-
-interface Promise<T> {
-    readonly [Symbol.toStringTag]: "Promise";
-}
-
-interface PromiseConstructor {
-    readonly [Symbol.species]: Function;
-}
-
-interface RegExp {
-        /**
-      * Matches a string with this regular expression, and returns an array containing the results of
-      * that search.
-      * @param string A string to search within.
-      */
-    [Symbol.match](string: string): RegExpMatchArray | null;
-
-    /**
-      * Replaces text in a string, using this regular expression.
-      * @param string A String object or string literal whose contents matching against
-      *               this regular expression will be replaced
-      * @param replaceValue A String object or string literal containing the text to replace for every 
-      *                     successful match of this regular expression.
-      */
-    [Symbol.replace](string: string, replaceValue: string): string;
-
-    /**
-      * Replaces text in a string, using this regular expression.
-      * @param string A String object or string literal whose contents matching against
-      *               this regular expression will be replaced
-      * @param replacer A function that returns the replacement text.
-      */
-    [Symbol.replace](string: string, replacer: (substring: string, ...args: any[]) => string): string;
-
-    /**
-      * Finds the position beginning first substring match in a regular expression search
-      * using this regular expression.
-      *
-      * @param string The string to search within.
-      */
-    [Symbol.search](string: string): number;
-
-    /**
-      * Returns an array of substrings that were delimited by strings in the original input that
-      * match against this regular expression.
-      *
-      * If the regular expression contains capturing parentheses, then each time this
-      * regular expression matches, the results (including any undefined results) of the
-      * capturing parentheses are spliced.
-      *
-      * @param string string value to split
-      * @param limit if not undefined, the output array is truncated so that it contains no more
-      * than 'limit' elements.
-      */
-    [Symbol.split](string: string, limit?: number): string[];
-}
-
-interface RegExpConstructor {
-    [Symbol.species](): RegExpConstructor;
-}
-
-interface String {
-    /**
-      * Matches a string an object that supports being matched against, and returns an array containing the results of that search.
-      * @param matcher An object that supports being matched against.
-      */
-    match(matcher: { [Symbol.match](string: string): RegExpMatchArray | null; }): RegExpMatchArray | null;
-
-    /**
-      * Replaces text in a string, using an object that supports replacement within a string.
-      * @param searchValue A object can search for and replace matches within a string.
-      * @param replaceValue A string containing the text to replace for every successful match of searchValue in this string.
-      */
-    replace(searchValue: { [Symbol.replace](string: string, replaceValue: string): string; }, replaceValue: string): string;
-
-    /**
-      * Replaces text in a string, using an object that supports replacement within a string.
-      * @param searchValue A object can search for and replace matches within a string.
-      * @param replacer A function that returns the replacement text.
-      */
-    replace(searchValue: { [Symbol.replace](string: string, replacer: (substring: string, ...args: any[]) => string): string; }, replacer: (substring: string, ...args: any[]) => string): string;
-
-    /**
-      * Finds the first substring match in a regular expression search.
-      * @param searcher An object which supports searching within a string.
-      */
-    search(searcher: { [Symbol.search](string: string): number; }): number;
-
-    /**
-      * Split a string into substrings using the specified separator and return them as an array.
-      * @param splitter An object that can split a string.
-      * @param limit A value used to limit the number of elements returned in the array.
-      */
-    split(splitter: { [Symbol.split](string: string, limit?: number): string[]; }, limit?: number): string[];
-}
-
-/**
-  * Represents a raw buffer of binary data, which is used to store data for the 
-  * different typed arrays. ArrayBuffers cannot be read from or written to directly, 
-  * but can be passed to a typed array or DataView Object to interpret the raw 
-  * buffer as needed. 
-  */
-interface ArrayBuffer {
-    readonly [Symbol.toStringTag]: "ArrayBuffer";
-}
-
-interface DataView {
-    readonly [Symbol.toStringTag]: "DataView";
-}
-
-/**
-  * A typed array of 8-bit integer values. The contents are initialized to 0. If the requested 
-  * number of bytes could not be allocated an exception is raised.
-  */
-interface Int8Array {
-    readonly [Symbol.toStringTag]: "Int8Array";
-}
-
-/**
-  * A typed array of 8-bit unsigned integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint8Array {
-    readonly [Symbol.toStringTag]: "UInt8Array";
-}
-
-/**
-  * A typed array of 8-bit unsigned integer (clamped) values. The contents are initialized to 0. 
-  * If the requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint8ClampedArray {
-    readonly [Symbol.toStringTag]: "Uint8ClampedArray";
-}
-
-/**
-  * A typed array of 16-bit signed integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Int16Array {
-    readonly [Symbol.toStringTag]: "Int16Array";
-}
-
-/**
-  * A typed array of 16-bit unsigned integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint16Array {
-    readonly [Symbol.toStringTag]: "Uint16Array";
-}
-
-/**
-  * A typed array of 32-bit signed integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Int32Array {
-    readonly [Symbol.toStringTag]: "Int32Array";
-}
-
-/**
-  * A typed array of 32-bit unsigned integer values. The contents are initialized to 0. If the 
-  * requested number of bytes could not be allocated an exception is raised.
-  */
-interface Uint32Array {
-    readonly [Symbol.toStringTag]: "Uint32Array";
-}
-
-/**
-  * A typed array of 32-bit float values. The contents are initialized to 0. If the requested number
-  * of bytes could not be allocated an exception is raised.
-  */
-interface Float32Array {
-    readonly [Symbol.toStringTag]: "Float32Array";
-}
-
-/**
-  * A typed array of 64-bit float values. The contents are initialized to 0. If the requested 
-  * number of bytes could not be allocated an exception is raised.
-  */
-interface Float64Array {
-    readonly [Symbol.toStringTag]: "Float64Array";
+/// <reference path="lib.es2015.symbol.d.ts" />
+
+interface SymbolConstructor {
+    /** 
+      * A method that determines if a constructor object recognizes an object as one of the 
+      * constructor’s instances. Called by the semantics of the instanceof operator. 
+      */
+    readonly hasInstance: symbol;
+
+    /** 
+      * A Boolean value that if true indicates that an object should flatten to its array elements
+      * by Array.prototype.concat.
+      */
+    readonly isConcatSpreadable: symbol;
+
+    /**
+      * A regular expression method that matches the regular expression against a string. Called 
+      * by the String.prototype.match method. 
+      */
+    readonly match: symbol;
+
+    /** 
+      * A regular expression method that replaces matched substrings of a string. Called by the 
+      * String.prototype.replace method.
+      */
+    readonly replace: symbol;
+
+    /**
+      * A regular expression method that returns the index within a string that matches the 
+      * regular expression. Called by the String.prototype.search method.
+      */
+    readonly search: symbol;
+
+    /** 
+      * A function valued property that is the constructor function that is used to create 
+      * derived objects.
+      */
+    readonly species: symbol;
+
+    /**
+      * A regular expression method that splits a string at the indices that match the regular 
+      * expression. Called by the String.prototype.split method.
+      */
+    readonly split: symbol;
+
+    /** 
+      * A method that converts an object to a corresponding primitive value.
+      * Called by the ToPrimitive abstract operation.
+      */
+    readonly toPrimitive: symbol;
+
+    /** 
+      * A String value that is used in the creation of the default string description of an object.
+      * Called by the built-in method Object.prototype.toString.
+      */
+    readonly toStringTag: symbol;
+
+    /**
+      * An Object whose own property names are property names that are excluded from the 'with'
+      * environment bindings of the associated objects.
+      */
+    readonly unscopables: symbol;
+}
+
+interface Symbol {
+    readonly [Symbol.toStringTag]: "Symbol";
+}
+
+interface Array<T> {
+    /**
+     * Returns an object whose properties have the value 'true'
+     * when they will be absent when used in a 'with' statement.
+     */
+    [Symbol.unscopables](): {
+        copyWithin: boolean;
+        entries: boolean;
+        fill: boolean;
+        find: boolean;
+        findIndex: boolean;
+        keys: boolean;
+        values: boolean;
+    };
+}
+
+interface Date {
+    /**
+     * Converts a Date object to a string.
+     */
+    [Symbol.toPrimitive](hint: "default"): string;
+    /**
+     * Converts a Date object to a string.
+     */
+    [Symbol.toPrimitive](hint: "string"): string;
+    /**
+     * Converts a Date object to a number.
+     */
+    [Symbol.toPrimitive](hint: "number"): number;
+    /**
+     * Converts a Date object to a string or number.
+     *
+     * @param hint The strings "number", "string", or "default" to specify what primitive to return.
+     *
+     * @throws {TypeError} If 'hint' was given something other than "number", "string", or "default".
+     * @returns A number if 'hint' was "number", a string if 'hint' was "string" or "default".
+     */
+    [Symbol.toPrimitive](hint: string): string | number;
+}
+
+interface Map<K, V> {
+    readonly [Symbol.toStringTag]: "Map";
+}
+
+interface WeakMap<K, V>{
+    readonly [Symbol.toStringTag]: "WeakMap";
+}
+
+interface Set<T> {
+    readonly [Symbol.toStringTag]: "Set";
+}
+
+interface WeakSet<T> {
+    readonly [Symbol.toStringTag]: "WeakSet";
+}
+
+interface JSON {
+    readonly [Symbol.toStringTag]: "JSON";
+}
+
+interface Function {
+    /**
+     * Determines whether the given value inherits from this function if this function was used
+     * as a constructor function.
+     *
+     * A constructor function can control which objects are recognized as its instances by
+     * 'instanceof' by overriding this method.
+     */
+    [Symbol.hasInstance](value: any): boolean;
+}
+
+interface GeneratorFunction extends Function {
+    readonly [Symbol.toStringTag]: "GeneratorFunction";
+}
+
+interface Math {
+    readonly [Symbol.toStringTag]: "Math";
+}
+
+interface Promise<T> {
+    readonly [Symbol.toStringTag]: "Promise";
+}
+
+interface PromiseConstructor {
+    readonly [Symbol.species]: Function;
+}
+
+interface RegExp {
+        /**
+      * Matches a string with this regular expression, and returns an array containing the results of
+      * that search.
+      * @param string A string to search within.
+      */
+    [Symbol.match](string: string): RegExpMatchArray | null;
+
+    /**
+      * Replaces text in a string, using this regular expression.
+      * @param string A String object or string literal whose contents matching against
+      *               this regular expression will be replaced
+      * @param replaceValue A String object or string literal containing the text to replace for every 
+      *                     successful match of this regular expression.
+      */
+    [Symbol.replace](string: string, replaceValue: string): string;
+
+    /**
+      * Replaces text in a string, using this regular expression.
+      * @param string A String object or string literal whose contents matching against
+      *               this regular expression will be replaced
+      * @param replacer A function that returns the replacement text.
+      */
+    [Symbol.replace](string: string, replacer: (substring: string, ...args: any[]) => string): string;
+
+    /**
+      * Finds the position beginning first substring match in a regular expression search
+      * using this regular expression.
+      *
+      * @param string The string to search within.
+      */
+    [Symbol.search](string: string): number;
+
+    /**
+      * Returns an array of substrings that were delimited by strings in the original input that
+      * match against this regular expression.
+      *
+      * If the regular expression contains capturing parentheses, then each time this
+      * regular expression matches, the results (including any undefined results) of the
+      * capturing parentheses are spliced.
+      *
+      * @param string string value to split
+      * @param limit if not undefined, the output array is truncated so that it contains no more
+      * than 'limit' elements.
+      */
+    [Symbol.split](string: string, limit?: number): string[];
+}
+
+interface RegExpConstructor {
+    [Symbol.species](): RegExpConstructor;
+}
+
+interface String {
+    /**
+      * Matches a string an object that supports being matched against, and returns an array containing the results of that search.
+      * @param matcher An object that supports being matched against.
+      */
+    match(matcher: { [Symbol.match](string: string): RegExpMatchArray | null; }): RegExpMatchArray | null;
+
+    /**
+      * Replaces text in a string, using an object that supports replacement within a string.
+      * @param searchValue A object can search for and replace matches within a string.
+      * @param replaceValue A string containing the text to replace for every successful match of searchValue in this string.
+      */
+    replace(searchValue: { [Symbol.replace](string: string, replaceValue: string): string; }, replaceValue: string): string;
+
+    /**
+      * Replaces text in a string, using an object that supports replacement within a string.
+      * @param searchValue A object can search for and replace matches within a string.
+      * @param replacer A function that returns the replacement text.
+      */
+    replace(searchValue: { [Symbol.replace](string: string, replacer: (substring: string, ...args: any[]) => string): string; }, replacer: (substring: string, ...args: any[]) => string): string;
+
+    /**
+      * Finds the first substring match in a regular expression search.
+      * @param searcher An object which supports searching within a string.
+      */
+    search(searcher: { [Symbol.search](string: string): number; }): number;
+
+    /**
+      * Split a string into substrings using the specified separator and return them as an array.
+      * @param splitter An object that can split a string.
+      * @param limit A value used to limit the number of elements returned in the array.
+      */
+    split(splitter: { [Symbol.split](string: string, limit?: number): string[]; }, limit?: number): string[];
+}
+
+/**
+  * Represents a raw buffer of binary data, which is used to store data for the 
+  * different typed arrays. ArrayBuffers cannot be read from or written to directly, 
+  * but can be passed to a typed array or DataView Object to interpret the raw 
+  * buffer as needed. 
+  */
+interface ArrayBuffer {
+    readonly [Symbol.toStringTag]: "ArrayBuffer";
+}
+
+interface DataView {
+    readonly [Symbol.toStringTag]: "DataView";
+}
+
+/**
+  * A typed array of 8-bit integer values. The contents are initialized to 0. If the requested 
+  * number of bytes could not be allocated an exception is raised.
+  */
+interface Int8Array {
+    readonly [Symbol.toStringTag]: "Int8Array";
+}
+
+/**
+  * A typed array of 8-bit unsigned integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint8Array {
+    readonly [Symbol.toStringTag]: "UInt8Array";
+}
+
+/**
+  * A typed array of 8-bit unsigned integer (clamped) values. The contents are initialized to 0. 
+  * If the requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint8ClampedArray {
+    readonly [Symbol.toStringTag]: "Uint8ClampedArray";
+}
+
+/**
+  * A typed array of 16-bit signed integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Int16Array {
+    readonly [Symbol.toStringTag]: "Int16Array";
+}
+
+/**
+  * A typed array of 16-bit unsigned integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint16Array {
+    readonly [Symbol.toStringTag]: "Uint16Array";
+}
+
+/**
+  * A typed array of 32-bit signed integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Int32Array {
+    readonly [Symbol.toStringTag]: "Int32Array";
+}
+
+/**
+  * A typed array of 32-bit unsigned integer values. The contents are initialized to 0. If the 
+  * requested number of bytes could not be allocated an exception is raised.
+  */
+interface Uint32Array {
+    readonly [Symbol.toStringTag]: "Uint32Array";
+}
+
+/**
+  * A typed array of 32-bit float values. The contents are initialized to 0. If the requested number
+  * of bytes could not be allocated an exception is raised.
+  */
+interface Float32Array {
+    readonly [Symbol.toStringTag]: "Float32Array";
+}
+
+/**
+  * A typed array of 64-bit float values. The contents are initialized to 0. If the requested 
+  * number of bytes could not be allocated an exception is raised.
+  */
+interface Float64Array {
+    readonly [Symbol.toStringTag]: "Float64Array";
 }

lib/lib.es2016.array.include.d.ts

@@ -1,109 +1,118 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-interface Array<T> {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: T, fromIndex?: number): boolean;
-}
-
-interface Int8Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Uint8Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Uint8ClampedArray {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Int16Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Uint16Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Int32Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Uint32Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Float32Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
-}
-
-interface Float64Array {
-    /**
-      * Determines whether an array includes a certain element, returning true or false as appropriate.
-      * @param searchElement The element to search for.
-      * @param fromIndex The position in this array at which to begin searching for searchElement.
-      */
-    includes(searchElement: number, fromIndex?: number): boolean;
+interface Array<T> {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: T, fromIndex?: number): boolean;
+}
+
+interface ReadonlyArray<T> {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: T, fromIndex?: number): boolean;
+}
+
+interface Int8Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Uint8Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Uint8ClampedArray {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Int16Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Uint16Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Int32Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Uint32Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Float32Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
+}
+
+interface Float64Array {
+    /**
+      * Determines whether an array includes a certain element, returning true or false as appropriate.
+      * @param searchElement The element to search for.
+      * @param fromIndex The position in this array at which to begin searching for searchElement.
+      */
+    includes(searchElement: number, fromIndex?: number): boolean;
 }

lib/lib.es2016.d.ts

@@ -1,22 +1,22 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/// <reference path="lib.es2015.d.ts" />
+/// <reference path="lib.es2015.d.ts" />
 /// <reference path="lib.es2016.array.include.d.ts" />

lib/lib.es2017.d.ts

@@ -1,23 +1,24 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/// <reference path="lib.es2016.d.ts" />
-/// <reference path="lib.es2017.object.d.ts" />
-/// <reference path="lib.es2017.sharedmemory.d.ts" />
+/// <reference path="lib.es2016.d.ts" />
+/// <reference path="lib.es2017.object.d.ts" />
+/// <reference path="lib.es2017.sharedmemory.d.ts" />
+/// <reference path="lib.es2017.string.d.ts" />

lib/lib.es2017.object.d.ts

@@ -1,34 +1,45 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-interface ObjectConstructor {
-    /**
-      * Returns an array of values of the enumerable properties of an object
-      * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
-      */
-    values<T>(o: { [s: string]: T }): T[];
-    values(o: any): any[];
-    /**
-      * Returns an array of key/values of the enumerable properties of an object
-      * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
-      */
-    entries<T>(o: { [s: string]: T }): [string, T][];
-    entries(o: any): [string, any][];
-}
+interface ObjectConstructor {
+    /**
+      * Returns an array of values of the enumerable properties of an object
+      * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
+      */
+    values<T>(o: { [s: string]: T }): T[];
+
+    /**
+      * Returns an array of values of the enumerable properties of an object
+      * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
+      */
+    values(o: any): any[];
+
+    /**
+      * Returns an array of key/values of the enumerable properties of an object
+      * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
+      */
+    entries<T>(o: { [s: string]: T }): [string, T][];
+
+    /**
+      * Returns an array of key/values of the enumerable properties of an object
+      * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
+      */
+    entries(o: any): [string, any][];
+}

lib/lib.es2017.sharedmemory.d.ts

@@ -1,47 +1,47 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-/// <reference path="lib.es2015.symbol.d.ts" />
-/// <reference path="lib.es2015.symbol.wellknown.d.ts" />
-
-interface SharedArrayBuffer {
-    /**
-      * Read-only. The length of the ArrayBuffer (in bytes).
-      */
-    readonly byteLength: number;
-
-    /*
-     * The SharedArrayBuffer constructor's length property whose value is 1.
-     */
-    length: number;
-    /**
-      * Returns a section of an SharedArrayBuffer.
-      */ 
-    slice(begin:number, end?:number): SharedArrayBuffer;
-    readonly [Symbol.species]: SharedArrayBuffer;
-    readonly [Symbol.toStringTag]: "SharedArrayBuffer";
-}
-
-interface SharedArrayBufferConstructor {
-    readonly prototype: SharedArrayBuffer;
-    new (byteLength: number): SharedArrayBuffer;
-}
-
+/// <reference path="lib.es2015.symbol.d.ts" />
+/// <reference path="lib.es2015.symbol.wellknown.d.ts" />
+
+interface SharedArrayBuffer {
+    /**
+      * Read-only. The length of the ArrayBuffer (in bytes).
+      */
+    readonly byteLength: number;
+
+    /*
+     * The SharedArrayBuffer constructor's length property whose value is 1.
+     */
+    length: number;
+    /**
+      * Returns a section of an SharedArrayBuffer.
+      */ 
+    slice(begin:number, end?:number): SharedArrayBuffer;
+    readonly [Symbol.species]: SharedArrayBuffer;
+    readonly [Symbol.toStringTag]: "SharedArrayBuffer";
+}
+
+interface SharedArrayBufferConstructor {
+    readonly prototype: SharedArrayBuffer;
+    new (byteLength: number): SharedArrayBuffer;
+}
+
 declare var SharedArrayBuffer: SharedArrayBufferConstructor;

lib/lib.es2017.string.d.ts

@@ -0,0 +1,47 @@
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
+
+
+
+/// <reference no-default-lib="true"/>
+
+
+interface String {
+    /**
+      * Pads the current string with a given string (possibly repeated) so that the resulting string reaches a given length.
+      * The padding is applied from the start (left) of the current string.
+      *
+      * @param maxLength The length of the resulting string once the current string has been padded.
+      *        If this parameter is smaller than the current string's length, the current string will be returned as it is.
+      *
+      * @param fillString The string to pad the current string with.
+      *        If this string is too long, it will be truncated and the left-most part will be applied.
+      *        The default value for this parameter is " " (U+0020).
+      */
+    padStart(maxLength: number, fillString?: string): string;
+
+    /**
+      * Pads the current string with a given string (possibly repeated) so that the resulting string reaches a given length.
+      * The padding is applied from the end (right) of the current string.
+      *
+      * @param maxLength The length of the resulting string once the current string has been padded.
+      *        If this parameter is smaller than the current string's length, the current string will be returned as it is.
+      *
+      * @param fillString The string to pad the current string with.
+      *        If this string is too long, it will be truncated and the left-most part will be applied.
+      *        The default value for this parameter is " " (U+0020).
+      */
+    padEnd(maxLength: number, fillString?: string): string;
+}

lib/lib.scripthost.d.ts

@@ -1,311 +1,311 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
 
 
-/// <reference no-default-lib="true"/>
+
+/// <reference no-default-lib="true"/>
 
 
-
-
-/////////////////////////////
-/// Windows Script Host APIS
-/////////////////////////////
-
-
-interface ActiveXObject {
-    new (s: string): any;
-}
-declare var ActiveXObject: ActiveXObject;
-
-interface ITextWriter {
-    Write(s: string): void;
-    WriteLine(s: string): void;
-    Close(): void;
-}
-
-interface TextStreamBase {
-    /**
-     * The column number of the current character position in an input stream.
-     */
-    Column: number;
-
-    /**
-     * The current line number in an input stream.
-     */
-    Line: number;
-
-    /**
-     * Closes a text stream.
-     * It is not necessary to close standard streams; they close automatically when the process ends. If 
-     * you close a standard stream, be aware that any other pointers to that standard stream become invalid.
-     */
-    Close(): void;
-}
-
-interface TextStreamWriter extends TextStreamBase {
-    /**
-     * Sends a string to an output stream.
-     */
-    Write(s: string): void;
-
-    /**
-     * Sends a specified number of blank lines (newline characters) to an output stream.
-     */
-    WriteBlankLines(intLines: number): void;
-
-    /**
-     * Sends a string followed by a newline character to an output stream.
-     */
-    WriteLine(s: string): void;
-}
-
-interface TextStreamReader extends TextStreamBase {
-    /**
-     * Returns a specified number of characters from an input stream, starting at the current pointer position.
-     * Does not return until the ENTER key is pressed.
-     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
-     */
-    Read(characters: number): string;
-
-    /**
-     * Returns all characters from an input stream.
-     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
-     */
-    ReadAll(): string;
-
-    /**
-     * Returns an entire line from an input stream.
-     * Although this method extracts the newline character, it does not add it to the returned string.
-     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
-     */
-    ReadLine(): string;
-
-    /**
-     * Skips a specified number of characters when reading from an input text stream.
-     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
-     * @param characters Positive number of characters to skip forward. (Backward skipping is not supported.)
-     */
-    Skip(characters: number): void;
-
-    /**
-     * Skips the next line when reading from an input text stream.
-     * Can only be used on a stream in reading mode, not writing or appending mode.
-     */
-    SkipLine(): void;
-
-    /**
-     * Indicates whether the stream pointer position is at the end of a line.
-     */
-    AtEndOfLine: boolean;
-
-    /**
-     * Indicates whether the stream pointer position is at the end of a stream.
-     */
-    AtEndOfStream: boolean;
-}
-
-declare var WScript: {
-    /**
-    * Outputs text to either a message box (under WScript.exe) or the command console window followed by
-    * a newline (under CScript.exe).
-    */
-    Echo(s: any): void;
-
-    /**
-     * Exposes the write-only error output stream for the current script.
-     * Can be accessed only while using CScript.exe.
-     */
-    StdErr: TextStreamWriter;
-
-    /**
-     * Exposes the write-only output stream for the current script.
-     * Can be accessed only while using CScript.exe.
-     */
-    StdOut: TextStreamWriter;
-    Arguments: { length: number; Item(n: number): string; };
-
-    /**
-     *  The full path of the currently running script.
-     */
-    ScriptFullName: string;
-
-    /**
-     * Forces the script to stop immediately, with an optional exit code.
-     */
-    Quit(exitCode?: number): number;
-
-    /**
-     * The Windows Script Host build version number.
-     */
-    BuildVersion: number;
-
-    /**
-     * Fully qualified path of the host executable.
-     */
-    FullName: string;
-
-    /**
-     * Gets/sets the script mode - interactive(true) or batch(false).
-     */
-    Interactive: boolean;
-
-    /**
-     * The name of the host executable (WScript.exe or CScript.exe).
-     */
-    Name: string;
-
-    /**
-     * Path of the directory containing the host executable.
-     */
-    Path: string;
-
-    /**
-     * The filename of the currently running script.
-     */
-    ScriptName: string;
-
-    /**
-     * Exposes the read-only input stream for the current script.
-     * Can be accessed only while using CScript.exe.
-     */
-    StdIn: TextStreamReader;
-
-    /**
-     * Windows Script Host version
-     */
-    Version: string;
-
-    /**
-     * Connects a COM object's event sources to functions named with a given prefix, in the form prefix_event.
-     */
-    ConnectObject(objEventSource: any, strPrefix: string): void;
-
-    /**
-     * Creates a COM object.
-     * @param strProgiID
-     * @param strPrefix Function names in the form prefix_event will be bound to this object's COM events.
-     */
-    CreateObject(strProgID: string, strPrefix?: string): any;
-
-    /**
-     * Disconnects a COM object from its event sources.
-     */
-    DisconnectObject(obj: any): void;
-
-    /**
-     * Retrieves an existing object with the specified ProgID from memory, or creates a new one from a file.
-     * @param strPathname Fully qualified path to the file containing the object persisted to disk.
-     *                       For objects in memory, pass a zero-length string.
-     * @param strProgID
-     * @param strPrefix Function names in the form prefix_event will be bound to this object's COM events.
-     */
-    GetObject(strPathname: string, strProgID?: string, strPrefix?: string): any;
-
-    /**
-     * Suspends script execution for a specified length of time, then continues execution.
-     * @param intTime Interval (in milliseconds) to suspend script execution.
-     */
-    Sleep(intTime: number): void;
-};
-
-/**
- * Allows enumerating over a COM collection, which may not have indexed item access.
- */
-interface Enumerator<T> {
-    /**
-     * Returns true if the current item is the last one in the collection, or the collection is empty,
-     * or the current item is undefined.
-     */
-    atEnd(): boolean;
-
-    /**
-     * Returns the current item in the collection
-     */
-    item(): T;
-
-    /**
-     * Resets the current item in the collection to the first item. If there are no items in the collection,
-     * the current item is set to undefined.
-     */
-    moveFirst(): void;
-
-    /**
-     * Moves the current item to the next item in the collection. If the enumerator is at the end of
-     * the collection or the collection is empty, the current item is set to undefined.
-     */
-    moveNext(): void;
-}
-
-interface EnumeratorConstructor {
-    new <T>(collection: any): Enumerator<T>;
-    new (collection: any): Enumerator<any>;
-}
-
-declare var Enumerator: EnumeratorConstructor;
-
-/**
- * Enables reading from a COM safe array, which might have an alternate lower bound, or multiple dimensions.
- */
-interface VBArray<T> {
-    /**
-     * Returns the number of dimensions (1-based).
-     */
-    dimensions(): number;
-
-    /**
-     * Takes an index for each dimension in the array, and returns the item at the corresponding location.
-     */
-    getItem(dimension1Index: number, ...dimensionNIndexes: number[]): T;
-
-    /**
-     * Returns the smallest available index for a given dimension.
-     * @param dimension 1-based dimension (defaults to 1)
-     */
-    lbound(dimension?: number): number;
-
-    /**
-     * Returns the largest available index for a given dimension.
-     * @param dimension 1-based dimension (defaults to 1)
-     */
-    ubound(dimension?: number): number;
-
-    /**
-     * Returns a Javascript array with all the elements in the VBArray. If there are multiple dimensions,
-     * each successive dimension is appended to the end of the array.
-     * Example: [[1,2,3],[4,5,6]] becomes [1,2,3,4,5,6]
-     */
-    toArray(): T[];
-}
-
-interface VBArrayConstructor {
-    new <T>(safeArray: any): VBArray<T>;
-    new (safeArray: any): VBArray<any>;
-}
-
-declare var VBArray: VBArrayConstructor;
-
-/**
- * Automation date (VT_DATE)
- */
-interface VarDate { }
-
-interface DateConstructor {
-    new (vd: VarDate): Date;
-}
-
-interface Date {
-    getVarDate: () => VarDate;
-}
+
+
+/////////////////////////////
+/// Windows Script Host APIS
+/////////////////////////////
+
+
+interface ActiveXObject {
+    new (s: string): any;
+}
+declare var ActiveXObject: ActiveXObject;
+
+interface ITextWriter {
+    Write(s: string): void;
+    WriteLine(s: string): void;
+    Close(): void;
+}
+
+interface TextStreamBase {
+    /**
+     * The column number of the current character position in an input stream.
+     */
+    Column: number;
+
+    /**
+     * The current line number in an input stream.
+     */
+    Line: number;
+
+    /**
+     * Closes a text stream.
+     * It is not necessary to close standard streams; they close automatically when the process ends. If 
+     * you close a standard stream, be aware that any other pointers to that standard stream become invalid.
+     */
+    Close(): void;
+}
+
+interface TextStreamWriter extends TextStreamBase {
+    /**
+     * Sends a string to an output stream.
+     */
+    Write(s: string): void;
+
+    /**
+     * Sends a specified number of blank lines (newline characters) to an output stream.
+     */
+    WriteBlankLines(intLines: number): void;
+
+    /**
+     * Sends a string followed by a newline character to an output stream.
+     */
+    WriteLine(s: string): void;
+}
+
+interface TextStreamReader extends TextStreamBase {
+    /**
+     * Returns a specified number of characters from an input stream, starting at the current pointer position.
+     * Does not return until the ENTER key is pressed.
+     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
+     */
+    Read(characters: number): string;
+
+    /**
+     * Returns all characters from an input stream.
+     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
+     */
+    ReadAll(): string;
+
+    /**
+     * Returns an entire line from an input stream.
+     * Although this method extracts the newline character, it does not add it to the returned string.
+     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
+     */
+    ReadLine(): string;
+
+    /**
+     * Skips a specified number of characters when reading from an input text stream.
+     * Can only be used on a stream in reading mode; causes an error in writing or appending mode.
+     * @param characters Positive number of characters to skip forward. (Backward skipping is not supported.)
+     */
+    Skip(characters: number): void;
+
+    /**
+     * Skips the next line when reading from an input text stream.
+     * Can only be used on a stream in reading mode, not writing or appending mode.
+     */
+    SkipLine(): void;
+
+    /**
+     * Indicates whether the stream pointer position is at the end of a line.
+     */
+    AtEndOfLine: boolean;
+
+    /**
+     * Indicates whether the stream pointer position is at the end of a stream.
+     */
+    AtEndOfStream: boolean;
+}
+
+declare var WScript: {
+    /**
+    * Outputs text to either a message box (under WScript.exe) or the command console window followed by
+    * a newline (under CScript.exe).
+    */
+    Echo(s: any): void;
+
+    /**
+     * Exposes the write-only error output stream for the current script.
+     * Can be accessed only while using CScript.exe.
+     */
+    StdErr: TextStreamWriter;
+
+    /**
+     * Exposes the write-only output stream for the current script.
+     * Can be accessed only while using CScript.exe.
+     */
+    StdOut: TextStreamWriter;
+    Arguments: { length: number; Item(n: number): string; };
+
+    /**
+     *  The full path of the currently running script.
+     */
+    ScriptFullName: string;
+
+    /**
+     * Forces the script to stop immediately, with an optional exit code.
+     */
+    Quit(exitCode?: number): number;
+
+    /**
+     * The Windows Script Host build version number.
+     */
+    BuildVersion: number;
+
+    /**
+     * Fully qualified path of the host executable.
+     */
+    FullName: string;
+
+    /**
+     * Gets/sets the script mode - interactive(true) or batch(false).
+     */
+    Interactive: boolean;
+
+    /**
+     * The name of the host executable (WScript.exe or CScript.exe).
+     */
+    Name: string;
+
+    /**
+     * Path of the directory containing the host executable.
+     */
+    Path: string;
+
+    /**
+     * The filename of the currently running script.
+     */
+    ScriptName: string;
+
+    /**
+     * Exposes the read-only input stream for the current script.
+     * Can be accessed only while using CScript.exe.
+     */
+    StdIn: TextStreamReader;
+
+    /**
+     * Windows Script Host version
+     */
+    Version: string;
+
+    /**
+     * Connects a COM object's event sources to functions named with a given prefix, in the form prefix_event.
+     */
+    ConnectObject(objEventSource: any, strPrefix: string): void;
+
+    /**
+     * Creates a COM object.
+     * @param strProgiID
+     * @param strPrefix Function names in the form prefix_event will be bound to this object's COM events.
+     */
+    CreateObject(strProgID: string, strPrefix?: string): any;
+
+    /**
+     * Disconnects a COM object from its event sources.
+     */
+    DisconnectObject(obj: any): void;
+
+    /**
+     * Retrieves an existing object with the specified ProgID from memory, or creates a new one from a file.
+     * @param strPathname Fully qualified path to the file containing the object persisted to disk.
+     *                       For objects in memory, pass a zero-length string.
+     * @param strProgID
+     * @param strPrefix Function names in the form prefix_event will be bound to this object's COM events.
+     */
+    GetObject(strPathname: string, strProgID?: string, strPrefix?: string): any;
+
+    /**
+     * Suspends script execution for a specified length of time, then continues execution.
+     * @param intTime Interval (in milliseconds) to suspend script execution.
+     */
+    Sleep(intTime: number): void;
+};
+
+/**
+ * Allows enumerating over a COM collection, which may not have indexed item access.
+ */
+interface Enumerator<T> {
+    /**
+     * Returns true if the current item is the last one in the collection, or the collection is empty,
+     * or the current item is undefined.
+     */
+    atEnd(): boolean;
+
+    /**
+     * Returns the current item in the collection
+     */
+    item(): T;
+
+    /**
+     * Resets the current item in the collection to the first item. If there are no items in the collection,
+     * the current item is set to undefined.
+     */
+    moveFirst(): void;
+
+    /**
+     * Moves the current item to the next item in the collection. If the enumerator is at the end of
+     * the collection or the collection is empty, the current item is set to undefined.
+     */
+    moveNext(): void;
+}
+
+interface EnumeratorConstructor {
+    new <T>(collection: any): Enumerator<T>;
+    new (collection: any): Enumerator<any>;
+}
+
+declare var Enumerator: EnumeratorConstructor;
+
+/**
+ * Enables reading from a COM safe array, which might have an alternate lower bound, or multiple dimensions.
+ */
+interface VBArray<T> {
+    /**
+     * Returns the number of dimensions (1-based).
+     */
+    dimensions(): number;
+
+    /**
+     * Takes an index for each dimension in the array, and returns the item at the corresponding location.
+     */
+    getItem(dimension1Index: number, ...dimensionNIndexes: number[]): T;
+
+    /**
+     * Returns the smallest available index for a given dimension.
+     * @param dimension 1-based dimension (defaults to 1)
+     */
+    lbound(dimension?: number): number;
+
+    /**
+     * Returns the largest available index for a given dimension.
+     * @param dimension 1-based dimension (defaults to 1)
+     */
+    ubound(dimension?: number): number;
+
+    /**
+     * Returns a Javascript array with all the elements in the VBArray. If there are multiple dimensions,
+     * each successive dimension is appended to the end of the array.
+     * Example: [[1,2,3],[4,5,6]] becomes [1,2,3,4,5,6]
+     */
+    toArray(): T[];
+}
+
+interface VBArrayConstructor {
+    new <T>(safeArray: any): VBArray<T>;
+    new (safeArray: any): VBArray<any>;
+}
+
+declare var VBArray: VBArrayConstructor;
+
+/**
+ * Automation date (VT_DATE)
+ */
+interface VarDate { }
+
+interface DateConstructor {
+    new (vd: VarDate): Date;
+}
+
+interface Date {
+    getVarDate: () => VarDate;
+}

lib/typescript.d.ts

@@ -1,18 +1,18 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
+
 declare namespace ts {
     interface MapLike<T> {
         [index: string]: T;
@@ -163,170 +163,179 @@ declare namespace ts {
         DeclareKeyword = 123,
         GetKeyword = 124,
         IsKeyword = 125,
-        ModuleKeyword = 126,
-        NamespaceKeyword = 127,
-        NeverKeyword = 128,
-        ReadonlyKeyword = 129,
-        RequireKeyword = 130,
-        NumberKeyword = 131,
-        SetKeyword = 132,
-        StringKeyword = 133,
-        SymbolKeyword = 134,
-        TypeKeyword = 135,
-        UndefinedKeyword = 136,
-        FromKeyword = 137,
-        GlobalKeyword = 138,
-        OfKeyword = 139,
-        QualifiedName = 140,
-        ComputedPropertyName = 141,
-        TypeParameter = 142,
-        Parameter = 143,
-        Decorator = 144,
-        PropertySignature = 145,
-        PropertyDeclaration = 146,
-        MethodSignature = 147,
-        MethodDeclaration = 148,
-        Constructor = 149,
-        GetAccessor = 150,
-        SetAccessor = 151,
-        CallSignature = 152,
-        ConstructSignature = 153,
-        IndexSignature = 154,
-        TypePredicate = 155,
-        TypeReference = 156,
-        FunctionType = 157,
-        ConstructorType = 158,
-        TypeQuery = 159,
-        TypeLiteral = 160,
-        ArrayType = 161,
-        TupleType = 162,
-        UnionType = 163,
-        IntersectionType = 164,
-        ParenthesizedType = 165,
-        ThisType = 166,
-        LiteralType = 167,
-        ObjectBindingPattern = 168,
-        ArrayBindingPattern = 169,
-        BindingElement = 170,
-        ArrayLiteralExpression = 171,
-        ObjectLiteralExpression = 172,
-        PropertyAccessExpression = 173,
-        ElementAccessExpression = 174,
-        CallExpression = 175,
-        NewExpression = 176,
-        TaggedTemplateExpression = 177,
-        TypeAssertionExpression = 178,
-        ParenthesizedExpression = 179,
-        FunctionExpression = 180,
-        ArrowFunction = 181,
-        DeleteExpression = 182,
-        TypeOfExpression = 183,
-        VoidExpression = 184,
-        AwaitExpression = 185,
-        PrefixUnaryExpression = 186,
-        PostfixUnaryExpression = 187,
-        BinaryExpression = 188,
-        ConditionalExpression = 189,
-        TemplateExpression = 190,
-        YieldExpression = 191,
-        SpreadElementExpression = 192,
-        ClassExpression = 193,
-        OmittedExpression = 194,
-        ExpressionWithTypeArguments = 195,
-        AsExpression = 196,
-        NonNullExpression = 197,
-        TemplateSpan = 198,
-        SemicolonClassElement = 199,
-        Block = 200,
-        VariableStatement = 201,
-        EmptyStatement = 202,
-        ExpressionStatement = 203,
-        IfStatement = 204,
-        DoStatement = 205,
-        WhileStatement = 206,
-        ForStatement = 207,
-        ForInStatement = 208,
-        ForOfStatement = 209,
-        ContinueStatement = 210,
-        BreakStatement = 211,
-        ReturnStatement = 212,
-        WithStatement = 213,
-        SwitchStatement = 214,
-        LabeledStatement = 215,
-        ThrowStatement = 216,
-        TryStatement = 217,
-        DebuggerStatement = 218,
-        VariableDeclaration = 219,
-        VariableDeclarationList = 220,
-        FunctionDeclaration = 221,
-        ClassDeclaration = 222,
-        InterfaceDeclaration = 223,
-        TypeAliasDeclaration = 224,
-        EnumDeclaration = 225,
-        ModuleDeclaration = 226,
-        ModuleBlock = 227,
-        CaseBlock = 228,
-        NamespaceExportDeclaration = 229,
-        ImportEqualsDeclaration = 230,
-        ImportDeclaration = 231,
-        ImportClause = 232,
-        NamespaceImport = 233,
-        NamedImports = 234,
-        ImportSpecifier = 235,
-        ExportAssignment = 236,
-        ExportDeclaration = 237,
-        NamedExports = 238,
-        ExportSpecifier = 239,
-        MissingDeclaration = 240,
-        ExternalModuleReference = 241,
-        JsxElement = 242,
-        JsxSelfClosingElement = 243,
-        JsxOpeningElement = 244,
-        JsxClosingElement = 245,
-        JsxAttribute = 246,
-        JsxSpreadAttribute = 247,
-        JsxExpression = 248,
-        CaseClause = 249,
-        DefaultClause = 250,
-        HeritageClause = 251,
-        CatchClause = 252,
-        PropertyAssignment = 253,
-        ShorthandPropertyAssignment = 254,
-        EnumMember = 255,
-        SourceFile = 256,
-        JSDocTypeExpression = 257,
-        JSDocAllType = 258,
-        JSDocUnknownType = 259,
-        JSDocArrayType = 260,
-        JSDocUnionType = 261,
-        JSDocTupleType = 262,
-        JSDocNullableType = 263,
-        JSDocNonNullableType = 264,
-        JSDocRecordType = 265,
-        JSDocRecordMember = 266,
-        JSDocTypeReference = 267,
-        JSDocOptionalType = 268,
-        JSDocFunctionType = 269,
-        JSDocVariadicType = 270,
-        JSDocConstructorType = 271,
-        JSDocThisType = 272,
-        JSDocComment = 273,
-        JSDocTag = 274,
-        JSDocParameterTag = 275,
-        JSDocReturnTag = 276,
-        JSDocTypeTag = 277,
-        JSDocTemplateTag = 278,
-        JSDocTypedefTag = 279,
-        JSDocPropertyTag = 280,
-        JSDocTypeLiteral = 281,
-        JSDocLiteralType = 282,
-        JSDocNullKeyword = 283,
-        JSDocUndefinedKeyword = 284,
-        JSDocNeverKeyword = 285,
-        SyntaxList = 286,
-        NotEmittedStatement = 287,
-        PartiallyEmittedExpression = 288,
-        Count = 289,
+        KeyOfKeyword = 126,
+        ModuleKeyword = 127,
+        NamespaceKeyword = 128,
+        NeverKeyword = 129,
+        ReadonlyKeyword = 130,
+        RequireKeyword = 131,
+        NumberKeyword = 132,
+        SetKeyword = 133,
+        StringKeyword = 134,
+        SymbolKeyword = 135,
+        TypeKeyword = 136,
+        UndefinedKeyword = 137,
+        FromKeyword = 138,
+        GlobalKeyword = 139,
+        OfKeyword = 140,
+        QualifiedName = 141,
+        ComputedPropertyName = 142,
+        TypeParameter = 143,
+        Parameter = 144,
+        Decorator = 145,
+        PropertySignature = 146,
+        PropertyDeclaration = 147,
+        MethodSignature = 148,
+        MethodDeclaration = 149,
+        Constructor = 150,
+        GetAccessor = 151,
+        SetAccessor = 152,
+        CallSignature = 153,
+        ConstructSignature = 154,
+        IndexSignature = 155,
+        TypePredicate = 156,
+        TypeReference = 157,
+        FunctionType = 158,
+        ConstructorType = 159,
+        TypeQuery = 160,
+        TypeLiteral = 161,
+        ArrayType = 162,
+        TupleType = 163,
+        UnionType = 164,
+        IntersectionType = 165,
+        ParenthesizedType = 166,
+        ThisType = 167,
+        TypeOperator = 168,
+        IndexedAccessType = 169,
+        MappedType = 170,
+        LiteralType = 171,
+        ObjectBindingPattern = 172,
+        ArrayBindingPattern = 173,
+        BindingElement = 174,
+        ArrayLiteralExpression = 175,
+        ObjectLiteralExpression = 176,
+        PropertyAccessExpression = 177,
+        ElementAccessExpression = 178,
+        CallExpression = 179,
+        NewExpression = 180,
+        TaggedTemplateExpression = 181,
+        TypeAssertionExpression = 182,
+        ParenthesizedExpression = 183,
+        FunctionExpression = 184,
+        ArrowFunction = 185,
+        DeleteExpression = 186,
+        TypeOfExpression = 187,
+        VoidExpression = 188,
+        AwaitExpression = 189,
+        PrefixUnaryExpression = 190,
+        PostfixUnaryExpression = 191,
+        BinaryExpression = 192,
+        ConditionalExpression = 193,
+        TemplateExpression = 194,
+        YieldExpression = 195,
+        SpreadElement = 196,
+        ClassExpression = 197,
+        OmittedExpression = 198,
+        ExpressionWithTypeArguments = 199,
+        AsExpression = 200,
+        NonNullExpression = 201,
+        TemplateSpan = 202,
+        SemicolonClassElement = 203,
+        Block = 204,
+        VariableStatement = 205,
+        EmptyStatement = 206,
+        ExpressionStatement = 207,
+        IfStatement = 208,
+        DoStatement = 209,
+        WhileStatement = 210,
+        ForStatement = 211,
+        ForInStatement = 212,
+        ForOfStatement = 213,
+        ContinueStatement = 214,
+        BreakStatement = 215,
+        ReturnStatement = 216,
+        WithStatement = 217,
+        SwitchStatement = 218,
+        LabeledStatement = 219,
+        ThrowStatement = 220,
+        TryStatement = 221,
+        DebuggerStatement = 222,
+        VariableDeclaration = 223,
+        VariableDeclarationList = 224,
+        FunctionDeclaration = 225,
+        ClassDeclaration = 226,
+        InterfaceDeclaration = 227,
+        TypeAliasDeclaration = 228,
+        EnumDeclaration = 229,
+        ModuleDeclaration = 230,
+        ModuleBlock = 231,
+        CaseBlock = 232,
+        NamespaceExportDeclaration = 233,
+        ImportEqualsDeclaration = 234,
+        ImportDeclaration = 235,
+        ImportClause = 236,
+        NamespaceImport = 237,
+        NamedImports = 238,
+        ImportSpecifier = 239,
+        ExportAssignment = 240,
+        ExportDeclaration = 241,
+        NamedExports = 242,
+        ExportSpecifier = 243,
+        MissingDeclaration = 244,
+        ExternalModuleReference = 245,
+        JsxElement = 246,
+        JsxSelfClosingElement = 247,
+        JsxOpeningElement = 248,
+        JsxClosingElement = 249,
+        JsxAttribute = 250,
+        JsxSpreadAttribute = 251,
+        JsxExpression = 252,
+        CaseClause = 253,
+        DefaultClause = 254,
+        HeritageClause = 255,
+        CatchClause = 256,
+        PropertyAssignment = 257,
+        ShorthandPropertyAssignment = 258,
+        SpreadAssignment = 259,
+        EnumMember = 260,
+        SourceFile = 261,
+        JSDocTypeExpression = 262,
+        JSDocAllType = 263,
+        JSDocUnknownType = 264,
+        JSDocArrayType = 265,
+        JSDocUnionType = 266,
+        JSDocTupleType = 267,
+        JSDocNullableType = 268,
+        JSDocNonNullableType = 269,
+        JSDocRecordType = 270,
+        JSDocRecordMember = 271,
+        JSDocTypeReference = 272,
+        JSDocOptionalType = 273,
+        JSDocFunctionType = 274,
+        JSDocVariadicType = 275,
+        JSDocConstructorType = 276,
+        JSDocThisType = 277,
+        JSDocComment = 278,
+        JSDocTag = 279,
+        JSDocAugmentsTag = 280,
+        JSDocParameterTag = 281,
+        JSDocReturnTag = 282,
+        JSDocTypeTag = 283,
+        JSDocTemplateTag = 284,
+        JSDocTypedefTag = 285,
+        JSDocPropertyTag = 286,
+        JSDocTypeLiteral = 287,
+        JSDocLiteralType = 288,
+        JSDocNullKeyword = 289,
+        JSDocUndefinedKeyword = 290,
+        JSDocNeverKeyword = 291,
+        SyntaxList = 292,
+        NotEmittedStatement = 293,
+        PartiallyEmittedExpression = 294,
+        MergeDeclarationMarker = 295,
+        EndOfDeclarationMarker = 296,
+        RawExpression = 297,
+        Count = 298,
         FirstAssignment = 57,
         LastAssignment = 69,
         FirstCompoundAssignment = 58,
@@ -334,15 +343,15 @@ declare namespace ts {
         FirstReservedWord = 71,
         LastReservedWord = 106,
         FirstKeyword = 71,
-        LastKeyword = 139,
+        LastKeyword = 140,
         FirstFutureReservedWord = 107,
         LastFutureReservedWord = 115,
-        FirstTypeNode = 155,
-        LastTypeNode = 167,
+        FirstTypeNode = 156,
+        LastTypeNode = 171,
         FirstPunctuation = 16,
         LastPunctuation = 69,
         FirstToken = 0,
-        LastToken = 139,
+        LastToken = 140,
         FirstTriviaToken = 2,
         LastTriviaToken = 7,
         FirstLiteralToken = 8,
@@ -351,11 +360,11 @@ declare namespace ts {
         LastTemplateToken = 15,
         FirstBinaryOperator = 26,
         LastBinaryOperator = 69,
-        FirstNode = 140,
-        FirstJSDocNode = 257,
-        LastJSDocNode = 282,
-        FirstJSDocTagNode = 273,
-        LastJSDocTagNode = 285,
+        FirstNode = 141,
+        FirstJSDocNode = 262,
+        LastJSDocNode = 288,
+        FirstJSDocTagNode = 278,
+        LastJSDocTagNode = 291,
     }
     enum NodeFlags {
         None = 0,
@@ -369,25 +378,20 @@ declare namespace ts {
         HasImplicitReturn = 128,
         HasExplicitReturn = 256,
         GlobalAugmentation = 512,
-        HasClassExtends = 1024,
-        HasDecorators = 2048,
-        HasParamDecorators = 4096,
-        HasAsyncFunctions = 8192,
-        HasJsxSpreadAttributes = 16384,
-        DisallowInContext = 32768,
-        YieldContext = 65536,
-        DecoratorContext = 131072,
-        AwaitContext = 262144,
-        ThisNodeHasError = 524288,
-        JavaScriptFile = 1048576,
-        ThisNodeOrAnySubNodesHasError = 2097152,
-        HasAggregatedChildData = 4194304,
+        HasAsyncFunctions = 1024,
+        DisallowInContext = 2048,
+        YieldContext = 4096,
+        DecoratorContext = 8192,
+        AwaitContext = 16384,
+        ThisNodeHasError = 32768,
+        JavaScriptFile = 65536,
+        ThisNodeOrAnySubNodesHasError = 131072,
+        HasAggregatedChildData = 262144,
         BlockScoped = 3,
         ReachabilityCheckFlags = 384,
-        EmitHelperFlags = 31744,
-        ReachabilityAndEmitFlags = 32128,
-        ContextFlags = 1540096,
-        TypeExcludesFlags = 327680,
+        ReachabilityAndEmitFlags = 1408,
+        ContextFlags = 96256,
+        TypeExcludesFlags = 20480,
     }
     enum ModifierFlags {
         None = 0,
@@ -407,6 +411,7 @@ declare namespace ts {
         ParameterPropertyModifier = 92,
         NonPublicAccessibilityModifier = 24,
         TypeScriptModifier = 2270,
+        ExportDefault = 513,
     }
     enum JsxFlags {
         None = 0,
@@ -437,12 +442,14 @@ declare namespace ts {
     type EqualsGreaterThanToken = Token<SyntaxKind.EqualsGreaterThanToken>;
     type EndOfFileToken = Token<SyntaxKind.EndOfFileToken>;
     type AtToken = Token<SyntaxKind.AtToken>;
+    type ReadonlyToken = Token<SyntaxKind.ReadonlyKeyword>;
     type Modifier = Token<SyntaxKind.AbstractKeyword> | Token<SyntaxKind.AsyncKeyword> | Token<SyntaxKind.ConstKeyword> | Token<SyntaxKind.DeclareKeyword> | Token<SyntaxKind.DefaultKeyword> | Token<SyntaxKind.ExportKeyword> | Token<SyntaxKind.PublicKeyword> | Token<SyntaxKind.PrivateKeyword> | Token<SyntaxKind.ProtectedKeyword> | Token<SyntaxKind.ReadonlyKeyword> | Token<SyntaxKind.StaticKeyword>;
     type ModifiersArray = NodeArray<Modifier>;
     interface Identifier extends PrimaryExpression {
         kind: SyntaxKind.Identifier;
         text: string;
         originalKeywordKind?: SyntaxKind;
+        isInJSDocNamespace?: boolean;
     }
     interface TransientIdentifier extends Identifier {
         resolvedSymbol: Symbol;
@@ -453,14 +460,14 @@ declare namespace ts {
         right: Identifier;
     }
     type EntityName = Identifier | QualifiedName;
-    type PropertyName = Identifier | LiteralExpression | ComputedPropertyName;
-    type DeclarationName = Identifier | LiteralExpression | ComputedPropertyName | BindingPattern;
+    type PropertyName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName;
+    type DeclarationName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName | BindingPattern;
     interface Declaration extends Node {
         _declarationBrand: any;
         name?: DeclarationName;
     }
     interface DeclarationStatement extends Declaration, Statement {
-        name?: Identifier | LiteralExpression;
+        name?: Identifier | StringLiteral | NumericLiteral;
     }
     interface ComputedPropertyName extends Node {
         kind: SyntaxKind.ComputedPropertyName;
@@ -533,7 +540,7 @@ declare namespace ts {
         _objectLiteralBrandBrand: any;
         name?: PropertyName;
     }
-    type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration;
+    type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration | SpreadAssignment;
     interface PropertyAssignment extends ObjectLiteralElement {
         kind: SyntaxKind.PropertyAssignment;
         name: PropertyName;
@@ -547,6 +554,10 @@ declare namespace ts {
         equalsToken?: Token<SyntaxKind.EqualsToken>;
         objectAssignmentInitializer?: Expression;
     }
+    interface SpreadAssignment extends ObjectLiteralElement {
+        kind: SyntaxKind.SpreadAssignment;
+        expression: Expression;
+    }
     interface VariableLikeDeclaration extends Declaration {
         propertyName?: PropertyName;
         dotDotDotToken?: DotDotDotToken;
@@ -558,18 +569,16 @@ declare namespace ts {
     interface PropertyLikeDeclaration extends Declaration {
         name: PropertyName;
     }
-    interface BindingPattern extends Node {
-        elements: NodeArray<BindingElement | ArrayBindingElement>;
-    }
-    interface ObjectBindingPattern extends BindingPattern {
+    interface ObjectBindingPattern extends Node {
         kind: SyntaxKind.ObjectBindingPattern;
         elements: NodeArray<BindingElement>;
     }
-    type ArrayBindingElement = BindingElement | OmittedExpression;
-    interface ArrayBindingPattern extends BindingPattern {
+    interface ArrayBindingPattern extends Node {
         kind: SyntaxKind.ArrayBindingPattern;
         elements: NodeArray<ArrayBindingElement>;
     }
+    type BindingPattern = ObjectBindingPattern | ArrayBindingPattern;
+    type ArrayBindingElement = BindingElement | OmittedExpression;
     /**
      * Several node kinds share function-like features such as a signature,
      * a name, and a body. These nodes should extend FunctionLikeDeclaration.
@@ -677,6 +686,23 @@ declare namespace ts {
         kind: SyntaxKind.ParenthesizedType;
         type: TypeNode;
     }
+    interface TypeOperatorNode extends TypeNode {
+        kind: SyntaxKind.TypeOperator;
+        operator: SyntaxKind.KeyOfKeyword;
+        type: TypeNode;
+    }
+    interface IndexedAccessTypeNode extends TypeNode {
+        kind: SyntaxKind.IndexedAccessType;
+        objectType: TypeNode;
+        indexType: TypeNode;
+    }
+    interface MappedTypeNode extends TypeNode, Declaration {
+        kind: SyntaxKind.MappedType;
+        readonlyToken?: ReadonlyToken;
+        typeParameter: TypeParameterDeclaration;
+        questionToken?: QuestionToken;
+        type?: TypeNode;
+    }
     interface LiteralTypeNode extends TypeNode {
         kind: SyntaxKind.LiteralType;
         literal: Expression;
@@ -709,9 +735,6 @@ declare namespace ts {
         operand: LeftHandSideExpression;
         operator: PostfixUnaryOperator;
     }
-    interface PostfixExpression extends UnaryExpression {
-        _postfixExpressionBrand: any;
-    }
     interface LeftHandSideExpression extends IncrementExpression {
         _leftHandSideExpressionBrand: any;
     }
@@ -780,6 +803,25 @@ declare namespace ts {
         operatorToken: BinaryOperatorToken;
         right: Expression;
     }
+    type AssignmentOperatorToken = Token<AssignmentOperator>;
+    interface AssignmentExpression<TOperator extends AssignmentOperatorToken> extends BinaryExpression {
+        left: LeftHandSideExpression;
+        operatorToken: TOperator;
+    }
+    interface ObjectDestructuringAssignment extends AssignmentExpression<EqualsToken> {
+        left: ObjectLiteralExpression;
+    }
+    interface ArrayDestructuringAssignment extends AssignmentExpression<EqualsToken> {
+        left: ArrayLiteralExpression;
+    }
+    type DestructuringAssignment = ObjectDestructuringAssignment | ArrayDestructuringAssignment;
+    type BindingOrAssignmentElement = VariableDeclaration | ParameterDeclaration | BindingElement | PropertyAssignment | ShorthandPropertyAssignment | SpreadAssignment | OmittedExpression | SpreadElement | ArrayLiteralExpression | ObjectLiteralExpression | AssignmentExpression<EqualsToken> | Identifier | PropertyAccessExpression | ElementAccessExpression;
+    type BindingOrAssignmentElementRestIndicator = DotDotDotToken | SpreadElement | SpreadAssignment;
+    type BindingOrAssignmentElementTarget = BindingOrAssignmentPattern | Expression;
+    type ObjectBindingOrAssignmentPattern = ObjectBindingPattern | ObjectLiteralExpression;
+    type ArrayBindingOrAssignmentPattern = ArrayBindingPattern | ArrayLiteralExpression;
+    type AssignmentPattern = ObjectLiteralExpression | ArrayLiteralExpression;
+    type BindingOrAssignmentPattern = ObjectBindingOrAssignmentPattern | ArrayBindingOrAssignmentPattern;
     interface ConditionalExpression extends Expression {
         kind: SyntaxKind.ConditionalExpression;
         condition: Expression;
@@ -846,8 +888,8 @@ declare namespace ts {
         kind: SyntaxKind.ArrayLiteralExpression;
         elements: NodeArray<Expression>;
     }
-    interface SpreadElementExpression extends Expression {
-        kind: SyntaxKind.SpreadElementExpression;
+    interface SpreadElement extends Expression {
+        kind: SyntaxKind.SpreadElement;
         expression: Expression;
     }
     /**
@@ -1140,13 +1182,17 @@ declare namespace ts {
     type ModuleName = Identifier | StringLiteral;
     interface ModuleDeclaration extends DeclarationStatement {
         kind: SyntaxKind.ModuleDeclaration;
-        name: Identifier | LiteralExpression;
-        body?: ModuleBlock | NamespaceDeclaration;
+        name: Identifier | StringLiteral;
+        body?: ModuleBlock | NamespaceDeclaration | JSDocNamespaceDeclaration | Identifier;
     }
     interface NamespaceDeclaration extends ModuleDeclaration {
         name: Identifier;
         body: ModuleBlock | NamespaceDeclaration;
     }
+    interface JSDocNamespaceDeclaration extends ModuleDeclaration {
+        name: Identifier;
+        body: JSDocNamespaceDeclaration | Identifier;
+    }
     interface ModuleBlock extends Node, Statement {
         kind: SyntaxKind.ModuleBlock;
         statements: NodeArray<Statement>;
@@ -1288,7 +1334,7 @@ declare namespace ts {
     type JSDocTypeReferencingNode = JSDocThisType | JSDocConstructorType | JSDocVariadicType | JSDocOptionalType | JSDocNullableType | JSDocNonNullableType;
     interface JSDocRecordMember extends PropertySignature {
         kind: SyntaxKind.JSDocRecordMember;
-        name: Identifier | LiteralExpression;
+        name: Identifier | StringLiteral | NumericLiteral;
         type?: JSDocType;
     }
     interface JSDoc extends Node {
@@ -1304,6 +1350,10 @@ declare namespace ts {
     interface JSDocUnknownTag extends JSDocTag {
         kind: SyntaxKind.JSDocTag;
     }
+    interface JSDocAugmentsTag extends JSDocTag {
+        kind: SyntaxKind.JSDocAugmentsTag;
+        typeExpression: JSDocTypeExpression;
+    }
     interface JSDocTemplateTag extends JSDocTag {
         kind: SyntaxKind.JSDocTemplateTag;
         typeParameters: NodeArray<TypeParameterDeclaration>;
@@ -1318,6 +1368,7 @@ declare namespace ts {
     }
     interface JSDocTypedefTag extends JSDocTag, Declaration {
         kind: SyntaxKind.JSDocTypedefTag;
+        fullName?: JSDocNamespaceDeclaration | Identifier;
         name?: Identifier;
         typeExpression?: JSDocTypeExpression;
         jsDocTypeLiteral?: JSDocTypeLiteral;
@@ -1551,6 +1602,7 @@ declare namespace ts {
         getJsxIntrinsicTagNames(): Symbol[];
         isOptionalParameter(node: ParameterDeclaration): boolean;
         getAmbientModules(): Symbol[];
+        tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined;
     }
     interface SymbolDisplayBuilder {
         buildTypeDisplay(type: Type, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
@@ -1571,6 +1623,7 @@ declare namespace ts {
         writeSpace(text: string): void;
         writeStringLiteral(text: string): void;
         writeParameter(text: string): void;
+        writeProperty(text: string): void;
         writeSymbol(text: string, symbol: Symbol): void;
         writeLine(): void;
         increaseIndent(): void;
@@ -1708,27 +1761,24 @@ declare namespace ts {
         Null = 4096,
         Never = 8192,
         TypeParameter = 16384,
-        Class = 32768,
-        Interface = 65536,
-        Reference = 131072,
-        Tuple = 262144,
-        Union = 524288,
-        Intersection = 1048576,
-        Anonymous = 2097152,
-        Instantiated = 4194304,
+        Object = 32768,
+        Union = 65536,
+        Intersection = 131072,
+        Index = 262144,
+        IndexedAccess = 524288,
         Literal = 480,
         StringOrNumberLiteral = 96,
         PossiblyFalsy = 7406,
-        StringLike = 34,
+        StringLike = 262178,
         NumberLike = 340,
         BooleanLike = 136,
         EnumLike = 272,
-        ObjectType = 2588672,
-        UnionOrIntersection = 1572864,
-        StructuredType = 4161536,
-        StructuredOrTypeParameter = 4177920,
-        Narrowable = 4178943,
-        NotUnionOrUnit = 2589185,
+        UnionOrIntersection = 196608,
+        StructuredType = 229376,
+        StructuredOrTypeParameter = 507904,
+        TypeVariable = 540672,
+        Narrowable = 1033215,
+        NotUnionOrUnit = 33281,
     }
     type DestructuringPattern = BindingPattern | ObjectLiteralExpression | ArrayLiteralExpression;
     interface Type {
@@ -1749,8 +1799,21 @@ declare namespace ts {
     interface EnumLiteralType extends LiteralType {
         baseType: EnumType & UnionType;
     }
+    enum ObjectFlags {
+        Class = 1,
+        Interface = 2,
+        Reference = 4,
+        Tuple = 8,
+        Anonymous = 16,
+        Mapped = 32,
+        Instantiated = 64,
+        ObjectLiteral = 128,
+        EvolvingArray = 256,
+        ObjectLiteralPatternWithComputedProperties = 512,
+        ClassOrInterface = 3,
+    }
     interface ObjectType extends Type {
-        isObjectLiteralPatternWithComputedProperties?: boolean;
+        objectFlags: ObjectFlags;
     }
     interface InterfaceType extends ObjectType {
         typeParameters: TypeParameter[];
@@ -1778,9 +1841,24 @@ declare namespace ts {
     }
     interface IntersectionType extends UnionOrIntersectionType {
     }
-    interface TypeParameter extends Type {
+    type StructuredType = ObjectType | UnionType | IntersectionType;
+    interface EvolvingArrayType extends ObjectType {
+        elementType: Type;
+        finalArrayType?: Type;
+    }
+    interface TypeVariable extends Type {
+    }
+    interface TypeParameter extends TypeVariable {
         constraint: Type;
     }
+    interface IndexedAccessType extends TypeVariable {
+        objectType: Type;
+        indexType: Type;
+        constraint?: Type;
+    }
+    interface IndexType extends Type {
+        type: TypeVariable | UnionOrIntersectionType;
+    }
     enum SignatureKind {
         Call = 0,
         Construct = 1,
@@ -1799,6 +1877,11 @@ declare namespace ts {
         isReadonly: boolean;
         declaration?: SignatureDeclaration;
     }
+    interface FileExtensionInfo {
+        extension: string;
+        scriptKind: ScriptKind;
+        isMixedContent: boolean;
+    }
     interface DiagnosticMessage {
         key: string;
         category: DiagnosticCategory;
@@ -1882,6 +1965,7 @@ declare namespace ts {
         preserveConstEnums?: boolean;
         project?: string;
         reactNamespace?: string;
+        jsxFactory?: string;
         removeComments?: boolean;
         rootDir?: string;
         rootDirs?: string[];
@@ -1895,12 +1979,13 @@ declare namespace ts {
         target?: ScriptTarget;
         traceResolution?: boolean;
         types?: string[];
-        /** Paths used to used to compute primary types search locations */
+        /** Paths used to compute primary types search locations */
         typeRoots?: string[];
         [option: string]: CompilerOptionsValue | undefined;
     }
-    interface TypingOptions {
+    interface TypeAcquisition {
         enableAutoDiscovery?: boolean;
+        enable?: boolean;
         include?: string[];
         exclude?: string[];
         [option: string]: string[] | boolean | undefined;
@@ -1910,8 +1995,9 @@ declare namespace ts {
         projectRootPath: string;
         safeListPath: string;
         packageNameToTypingLocation: Map<string>;
-        typingOptions: TypingOptions;
+        typeAcquisition: TypeAcquisition;
         compilerOptions: CompilerOptions;
+        unresolvedImports: ReadonlyArray<string>;
     }
     enum ModuleKind {
         None = 0,
@@ -1947,15 +2033,17 @@ declare namespace ts {
         ES2015 = 2,
         ES2016 = 3,
         ES2017 = 4,
-        Latest = 4,
+        ESNext = 5,
+        Latest = 5,
     }
     enum LanguageVariant {
         Standard = 0,
         JSX = 1,
     }
+    /** Either a parsed command line or a parsed tsconfig.json */
     interface ParsedCommandLine {
         options: CompilerOptions;
-        typingOptions?: TypingOptions;
+        typeAcquisition?: TypeAcquisition;
         fileNames: string[];
         raw?: any;
         errors: Diagnostic[];
@@ -1979,12 +2067,45 @@ declare namespace ts {
         getCurrentDirectory?(): string;
         getDirectories?(path: string): string[];
     }
+    /**
+     * Represents the result of module resolution.
+     * Module resolution will pick up tsx/jsx/js files even if '--jsx' and '--allowJs' are turned off.
+     * The Program will then filter results based on these flags.
+     *
+     * Prefer to return a `ResolvedModuleFull` so that the file type does not have to be inferred.
+     */
     interface ResolvedModule {
+        /** Path of the file the module was resolved to. */
         resolvedFileName: string;
+        /**
+         * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be a proper external module:
+         * - be a .d.ts file
+         * - use top level imports\exports
+         * - don't use tripleslash references
+         */
         isExternalLibraryImport?: boolean;
     }
+    /**
+     * ResolvedModule with an explicitly provided `extension` property.
+     * Prefer this over `ResolvedModule`.
+     */
+    interface ResolvedModuleFull extends ResolvedModule {
+        /**
+         * Extension of resolvedFileName. This must match what's at the end of resolvedFileName.
+         * This is optional for backwards-compatibility, but will be added if not provided.
+         */
+        extension: Extension;
+    }
+    enum Extension {
+        Ts = 0,
+        Tsx = 1,
+        Dts = 2,
+        Js = 3,
+        Jsx = 4,
+        LastTypeScriptExtension = 2,
+    }
     interface ResolvedModuleWithFailedLookupLocations {
-        resolvedModule: ResolvedModule;
+        resolvedModule: ResolvedModuleFull | undefined;
         failedLookupLocations: string[];
     }
     interface ResolvedTypeReferenceDirective {
@@ -2026,6 +2147,10 @@ declare namespace ts {
         _children: Node[];
     }
 }
+declare namespace ts {
+    /** The version of the TypeScript compiler release */
+    const version = "2.2.0";
+}
 declare namespace ts {
     type FileWatcherCallback = (fileName: string, removed?: boolean) => void;
     type DirectoryWatcherCallback = (fileName: string) => void;
@@ -2042,7 +2167,11 @@ declare namespace ts {
         readFile(path: string, encoding?: string): string;
         getFileSize?(path: string): number;
         writeFile(path: string, data: string, writeByteOrderMark?: boolean): void;
-        watchFile?(path: string, callback: FileWatcherCallback): FileWatcher;
+        /**
+         * @pollingInterval - this parameter is used in polling-based watchers and ignored in watchers that
+         * use native OS file watching
+         */
+        watchFile?(path: string, callback: FileWatcherCallback, pollingInterval?: number): FileWatcher;
         watchDirectory?(path: string, callback: DirectoryWatcherCallback, recursive?: boolean): FileWatcher;
         resolvePath(path: string): string;
         fileExists(path: string): boolean;
@@ -2057,6 +2186,8 @@ declare namespace ts {
         getMemoryUsage?(): number;
         exit(exitCode?: number): void;
         realpath?(path: string): string;
+        setTimeout?(callback: (...args: any[]) => void, ms: number, ...args: any[]): any;
+        clearTimeout?(timeoutId: any): void;
     }
     interface FileWatcher {
         close(): void;
@@ -2151,18 +2282,30 @@ declare namespace ts {
      */
     function collapseTextChangeRangesAcrossMultipleVersions(changes: TextChangeRange[]): TextChangeRange;
     function getTypeParameterOwner(d: Declaration): Declaration;
-    function isParameterPropertyDeclaration(node: ParameterDeclaration): boolean;
+    function isParameterPropertyDeclaration(node: Node): boolean;
     function getCombinedModifierFlags(node: Node): ModifierFlags;
     function getCombinedNodeFlags(node: Node): NodeFlags;
+    /**
+      * Checks to see if the locale is in the appropriate format,
+      * and if it is, attempts to set the appropriate language.
+      */
+    function validateLocaleAndSetLanguage(locale: string, sys: {
+        getExecutingFilePath(): string;
+        resolvePath(path: string): string;
+        fileExists(fileName: string): boolean;
+        readFile(fileName: string): string;
+    }, errors?: Diagnostic[]): void;
 }
 declare namespace ts {
     function createNode(kind: SyntaxKind, pos?: number, end?: number): Node;
     function forEachChild<T>(node: Node, cbNode: (node: Node) => T, cbNodeArray?: (nodes: Node[]) => T): T;
     function createSourceFile(fileName: string, sourceText: string, languageVersion: ScriptTarget, setParentNodes?: boolean, scriptKind?: ScriptKind): SourceFile;
+    function parseIsolatedEntityName(text: string, languageVersion: ScriptTarget): EntityName;
     function isExternalModule(file: SourceFile): boolean;
     function updateSourceFile(sourceFile: SourceFile, newText: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;
 }
 declare namespace ts {
+    function moduleHasNonRelativeName(moduleName: string): boolean;
     function getEffectiveTypeRoots(options: CompilerOptions, host: {
         directoryExists?: (directoryName: string) => boolean;
         getCurrentDirectory?: () => string;
@@ -2172,7 +2315,7 @@ declare namespace ts {
      * This is possible in case if resolution is performed for directives specified via 'types' parameter. In this case initial path for secondary lookups
      * is assumed to be the same as root directory of the project.
      */
-    function resolveTypeReferenceDirective(typeReferenceDirectiveName: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost): ResolvedTypeReferenceDirectiveWithFailedLookupLocations;
+    function resolveTypeReferenceDirective(typeReferenceDirectiveName: string, containingFile: string | undefined, options: CompilerOptions, host: ModuleResolutionHost): ResolvedTypeReferenceDirectiveWithFailedLookupLocations;
     /**
       * Given a set of options, returns the set of type directive names
       *   that should be included for this program automatically.
@@ -2187,8 +2330,6 @@ declare namespace ts {
     function classicNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations;
 }
 declare namespace ts {
-    /** The version of the TypeScript compiler release */
-    const version = "2.1.0";
     function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string;
     function resolveTripleslashReference(moduleName: string, containingFile: string): string;
     function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;
@@ -2203,6 +2344,7 @@ declare namespace ts {
     function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost, oldProgram?: Program): Program;
 }
 declare namespace ts {
+    function parseCommandLine(commandLine: string[], readFile?: (path: string) => string): ParsedCommandLine;
     /**
       * Read tsconfig.json file
       * @param fileName The path to the config file
@@ -2227,14 +2369,14 @@ declare namespace ts {
       * @param basePath A root directory to resolve relative path entries in the config
       *    file to. e.g. outDir
       */
-    function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions?: CompilerOptions, configFileName?: string, resolutionStack?: Path[]): ParsedCommandLine;
+    function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions?: CompilerOptions, configFileName?: string, resolutionStack?: Path[], extraFileExtensions?: FileExtensionInfo[]): ParsedCommandLine;
     function convertCompileOnSaveOptionFromJson(jsonOption: any, basePath: string, errors: Diagnostic[]): boolean;
     function convertCompilerOptionsFromJson(jsonOptions: any, basePath: string, configFileName?: string): {
         options: CompilerOptions;
         errors: Diagnostic[];
     };
-    function convertTypingOptionsFromJson(jsonOptions: any, basePath: string, configFileName?: string): {
-        options: TypingOptions;
+    function convertTypeAcquisitionFromJson(jsonOptions: any, basePath: string, configFileName?: string): {
+        options: TypeAcquisition;
         errors: Diagnostic[];
     };
 }
@@ -2283,6 +2425,7 @@ declare namespace ts {
     }
     interface SourceFile {
         getLineAndCharacterOfPosition(pos: number): LineAndCharacter;
+        getLineEndOfPosition(pos: number): number;
         getLineStarts(): number[];
         getPositionOfLineAndCharacter(line: number, character: number): number;
         update(newText: string, textChangeRange: TextChangeRange): SourceFile;
@@ -2988,5 +3131,5 @@ declare namespace ts {
       */
     function getDefaultLibFilePath(options: CompilerOptions): string;
 }
-
+
 export = ts;

lib/typescriptServices.d.ts

@@ -1,18 +1,18 @@
-/*! *****************************************************************************
-Copyright (c) Microsoft Corporation. All rights reserved. 
-Licensed under the Apache License, Version 2.0 (the "License"); you may not use
-this file except in compliance with the License. You may obtain a copy of the
-License at http://www.apache.org/licenses/LICENSE-2.0  
- 
-THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
-WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
-MERCHANTABLITY OR NON-INFRINGEMENT. 
- 
-See the Apache Version 2.0 License for specific language governing permissions
-and limitations under the License.
-***************************************************************************** */
-
+/*! *****************************************************************************
+Copyright (c) Microsoft Corporation. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at http://www.apache.org/licenses/LICENSE-2.0  
+ 
+THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE, 
+MERCHANTABLITY OR NON-INFRINGEMENT. 
+ 
+See the Apache Version 2.0 License for specific language governing permissions
+and limitations under the License.
+***************************************************************************** */
+
 declare namespace ts {
     interface MapLike<T> {
         [index: string]: T;
@@ -163,170 +163,179 @@ declare namespace ts {
         DeclareKeyword = 123,
         GetKeyword = 124,
         IsKeyword = 125,
-        ModuleKeyword = 126,
-        NamespaceKeyword = 127,
-        NeverKeyword = 128,
-        ReadonlyKeyword = 129,
-        RequireKeyword = 130,
-        NumberKeyword = 131,
-        SetKeyword = 132,
-        StringKeyword = 133,
-        SymbolKeyword = 134,
-        TypeKeyword = 135,
-        UndefinedKeyword = 136,
-        FromKeyword = 137,
-        GlobalKeyword = 138,
-        OfKeyword = 139,
-        QualifiedName = 140,
-        ComputedPropertyName = 141,
-        TypeParameter = 142,
-        Parameter = 143,
-        Decorator = 144,
-        PropertySignature = 145,
-        PropertyDeclaration = 146,
-        MethodSignature = 147,
-        MethodDeclaration = 148,
-        Constructor = 149,
-        GetAccessor = 150,
-        SetAccessor = 151,
-        CallSignature = 152,
-        ConstructSignature = 153,
-        IndexSignature = 154,
-        TypePredicate = 155,
-        TypeReference = 156,
-        FunctionType = 157,
-        ConstructorType = 158,
-        TypeQuery = 159,
-        TypeLiteral = 160,
-        ArrayType = 161,
-        TupleType = 162,
-        UnionType = 163,
-        IntersectionType = 164,
-        ParenthesizedType = 165,
-        ThisType = 166,
-        LiteralType = 167,
-        ObjectBindingPattern = 168,
-        ArrayBindingPattern = 169,
-        BindingElement = 170,
-        ArrayLiteralExpression = 171,
-        ObjectLiteralExpression = 172,
-        PropertyAccessExpression = 173,
-        ElementAccessExpression = 174,
-        CallExpression = 175,
-        NewExpression = 176,
-        TaggedTemplateExpression = 177,
-        TypeAssertionExpression = 178,
-        ParenthesizedExpression = 179,
-        FunctionExpression = 180,
-        ArrowFunction = 181,
-        DeleteExpression = 182,
-        TypeOfExpression = 183,
-        VoidExpression = 184,
-        AwaitExpression = 185,
-        PrefixUnaryExpression = 186,
-        PostfixUnaryExpression = 187,
-        BinaryExpression = 188,
-        ConditionalExpression = 189,
-        TemplateExpression = 190,
-        YieldExpression = 191,
-        SpreadElementExpression = 192,
-        ClassExpression = 193,
-        OmittedExpression = 194,
-        ExpressionWithTypeArguments = 195,
-        AsExpression = 196,
-        NonNullExpression = 197,
-        TemplateSpan = 198,
-        SemicolonClassElement = 199,
-        Block = 200,
-        VariableStatement = 201,
-        EmptyStatement = 202,
-        ExpressionStatement = 203,
-        IfStatement = 204,
-        DoStatement = 205,
-        WhileStatement = 206,
-        ForStatement = 207,
-        ForInStatement = 208,
-        ForOfStatement = 209,
-        ContinueStatement = 210,
-        BreakStatement = 211,
-        ReturnStatement = 212,
-        WithStatement = 213,
-        SwitchStatement = 214,
-        LabeledStatement = 215,
-        ThrowStatement = 216,
-        TryStatement = 217,
-        DebuggerStatement = 218,
-        VariableDeclaration = 219,
-        VariableDeclarationList = 220,
-        FunctionDeclaration = 221,
-        ClassDeclaration = 222,
-        InterfaceDeclaration = 223,
-        TypeAliasDeclaration = 224,
-        EnumDeclaration = 225,
-        ModuleDeclaration = 226,
-        ModuleBlock = 227,
-        CaseBlock = 228,
-        NamespaceExportDeclaration = 229,
-        ImportEqualsDeclaration = 230,
-        ImportDeclaration = 231,
-        ImportClause = 232,
-        NamespaceImport = 233,
-        NamedImports = 234,
-        ImportSpecifier = 235,
-        ExportAssignment = 236,
-        ExportDeclaration = 237,
-        NamedExports = 238,
-        ExportSpecifier = 239,
-        MissingDeclaration = 240,
-        ExternalModuleReference = 241,
-        JsxElement = 242,
-        JsxSelfClosingElement = 243,
-        JsxOpeningElement = 244,
-        JsxClosingElement = 245,
-        JsxAttribute = 246,
-        JsxSpreadAttribute = 247,
-        JsxExpression = 248,
-        CaseClause = 249,
-        DefaultClause = 250,
-        HeritageClause = 251,
-        CatchClause = 252,
-        PropertyAssignment = 253,
-        ShorthandPropertyAssignment = 254,
-        EnumMember = 255,
-        SourceFile = 256,
-        JSDocTypeExpression = 257,
-        JSDocAllType = 258,
-        JSDocUnknownType = 259,
-        JSDocArrayType = 260,
-        JSDocUnionType = 261,
-        JSDocTupleType = 262,
-        JSDocNullableType = 263,
-        JSDocNonNullableType = 264,
-        JSDocRecordType = 265,
-        JSDocRecordMember = 266,
-        JSDocTypeReference = 267,
-        JSDocOptionalType = 268,
-        JSDocFunctionType = 269,
-        JSDocVariadicType = 270,
-        JSDocConstructorType = 271,
-        JSDocThisType = 272,
-        JSDocComment = 273,
-        JSDocTag = 274,
-        JSDocParameterTag = 275,
-        JSDocReturnTag = 276,
-        JSDocTypeTag = 277,
-        JSDocTemplateTag = 278,
-        JSDocTypedefTag = 279,
-        JSDocPropertyTag = 280,
-        JSDocTypeLiteral = 281,
-        JSDocLiteralType = 282,
-        JSDocNullKeyword = 283,
-        JSDocUndefinedKeyword = 284,
-        JSDocNeverKeyword = 285,
-        SyntaxList = 286,
-        NotEmittedStatement = 287,
-        PartiallyEmittedExpression = 288,
-        Count = 289,
+        KeyOfKeyword = 126,
+        ModuleKeyword = 127,
+        NamespaceKeyword = 128,
+        NeverKeyword = 129,
+        ReadonlyKeyword = 130,
+        RequireKeyword = 131,
+        NumberKeyword = 132,
+        SetKeyword = 133,
+        StringKeyword = 134,
+        SymbolKeyword = 135,
+        TypeKeyword = 136,
+        UndefinedKeyword = 137,
+        FromKeyword = 138,
+        GlobalKeyword = 139,
+        OfKeyword = 140,
+        QualifiedName = 141,
+        ComputedPropertyName = 142,
+        TypeParameter = 143,
+        Parameter = 144,
+        Decorator = 145,
+        PropertySignature = 146,
+        PropertyDeclaration = 147,
+        MethodSignature = 148,
+        MethodDeclaration = 149,
+        Constructor = 150,
+        GetAccessor = 151,
+        SetAccessor = 152,
+        CallSignature = 153,
+        ConstructSignature = 154,
+        IndexSignature = 155,
+        TypePredicate = 156,
+        TypeReference = 157,
+        FunctionType = 158,
+        ConstructorType = 159,
+        TypeQuery = 160,
+        TypeLiteral = 161,
+        ArrayType = 162,
+        TupleType = 163,
+        UnionType = 164,
+        IntersectionType = 165,
+        ParenthesizedType = 166,
+        ThisType = 167,
+        TypeOperator = 168,
+        IndexedAccessType = 169,
+        MappedType = 170,
+        LiteralType = 171,
+        ObjectBindingPattern = 172,
+        ArrayBindingPattern = 173,
+        BindingElement = 174,
+        ArrayLiteralExpression = 175,
+        ObjectLiteralExpression = 176,
+        PropertyAccessExpression = 177,
+        ElementAccessExpression = 178,
+        CallExpression = 179,
+        NewExpression = 180,
+        TaggedTemplateExpression = 181,
+        TypeAssertionExpression = 182,
+        ParenthesizedExpression = 183,
+        FunctionExpression = 184,
+        ArrowFunction = 185,
+        DeleteExpression = 186,
+        TypeOfExpression = 187,
+        VoidExpression = 188,
+        AwaitExpression = 189,
+        PrefixUnaryExpression = 190,
+        PostfixUnaryExpression = 191,
+        BinaryExpression = 192,
+        ConditionalExpression = 193,
+        TemplateExpression = 194,
+        YieldExpression = 195,
+        SpreadElement = 196,
+        ClassExpression = 197,
+        OmittedExpression = 198,
+        ExpressionWithTypeArguments = 199,
+        AsExpression = 200,
+        NonNullExpression = 201,
+        TemplateSpan = 202,
+        SemicolonClassElement = 203,
+        Block = 204,
+        VariableStatement = 205,
+        EmptyStatement = 206,
+        ExpressionStatement = 207,
+        IfStatement = 208,
+        DoStatement = 209,
+        WhileStatement = 210,
+        ForStatement = 211,
+        ForInStatement = 212,
+        ForOfStatement = 213,
+        ContinueStatement = 214,
+        BreakStatement = 215,
+        ReturnStatement = 216,
+        WithStatement = 217,
+        SwitchStatement = 218,
+        LabeledStatement = 219,
+        ThrowStatement = 220,
+        TryStatement = 221,
+        DebuggerStatement = 222,
+        VariableDeclaration = 223,
+        VariableDeclarationList = 224,
+        FunctionDeclaration = 225,
+        ClassDeclaration = 226,
+        InterfaceDeclaration = 227,
+        TypeAliasDeclaration = 228,
+        EnumDeclaration = 229,
+        ModuleDeclaration = 230,
+        ModuleBlock = 231,
+        CaseBlock = 232,
+        NamespaceExportDeclaration = 233,
+        ImportEqualsDeclaration = 234,
+        ImportDeclaration = 235,
+        ImportClause = 236,
+        NamespaceImport = 237,
+        NamedImports = 238,
+        ImportSpecifier = 239,
+        ExportAssignment = 240,
+        ExportDeclaration = 241,
+        NamedExports = 242,
+        ExportSpecifier = 243,
+        MissingDeclaration = 244,
+        ExternalModuleReference = 245,
+        JsxElement = 246,
+        JsxSelfClosingElement = 247,
+        JsxOpeningElement = 248,
+        JsxClosingElement = 249,
+        JsxAttribute = 250,
+        JsxSpreadAttribute = 251,
+        JsxExpression = 252,
+        CaseClause = 253,
+        DefaultClause = 254,
+        HeritageClause = 255,
+        CatchClause = 256,
+        PropertyAssignment = 257,
+        ShorthandPropertyAssignment = 258,
+        SpreadAssignment = 259,
+        EnumMember = 260,
+        SourceFile = 261,
+        JSDocTypeExpression = 262,
+        JSDocAllType = 263,
+        JSDocUnknownType = 264,
+        JSDocArrayType = 265,
+        JSDocUnionType = 266,
+        JSDocTupleType = 267,
+        JSDocNullableType = 268,
+        JSDocNonNullableType = 269,
+        JSDocRecordType = 270,
+        JSDocRecordMember = 271,
+        JSDocTypeReference = 272,
+        JSDocOptionalType = 273,
+        JSDocFunctionType = 274,
+        JSDocVariadicType = 275,
+        JSDocConstructorType = 276,
+        JSDocThisType = 277,
+        JSDocComment = 278,
+        JSDocTag = 279,
+        JSDocAugmentsTag = 280,
+        JSDocParameterTag = 281,
+        JSDocReturnTag = 282,
+        JSDocTypeTag = 283,
+        JSDocTemplateTag = 284,
+        JSDocTypedefTag = 285,
+        JSDocPropertyTag = 286,
+        JSDocTypeLiteral = 287,
+        JSDocLiteralType = 288,
+        JSDocNullKeyword = 289,
+        JSDocUndefinedKeyword = 290,
+        JSDocNeverKeyword = 291,
+        SyntaxList = 292,
+        NotEmittedStatement = 293,
+        PartiallyEmittedExpression = 294,
+        MergeDeclarationMarker = 295,
+        EndOfDeclarationMarker = 296,
+        RawExpression = 297,
+        Count = 298,
         FirstAssignment = 57,
         LastAssignment = 69,
         FirstCompoundAssignment = 58,
@@ -334,15 +343,15 @@ declare namespace ts {
         FirstReservedWord = 71,
         LastReservedWord = 106,
         FirstKeyword = 71,
-        LastKeyword = 139,
+        LastKeyword = 140,
         FirstFutureReservedWord = 107,
         LastFutureReservedWord = 115,
-        FirstTypeNode = 155,
-        LastTypeNode = 167,
+        FirstTypeNode = 156,
+        LastTypeNode = 171,
         FirstPunctuation = 16,
         LastPunctuation = 69,
         FirstToken = 0,
-        LastToken = 139,
+        LastToken = 140,
         FirstTriviaToken = 2,
         LastTriviaToken = 7,
         FirstLiteralToken = 8,
@@ -351,11 +360,11 @@ declare namespace ts {
         LastTemplateToken = 15,
         FirstBinaryOperator = 26,
         LastBinaryOperator = 69,
-        FirstNode = 140,
-        FirstJSDocNode = 257,
-        LastJSDocNode = 282,
-        FirstJSDocTagNode = 273,
-        LastJSDocTagNode = 285,
+        FirstNode = 141,
+        FirstJSDocNode = 262,
+        LastJSDocNode = 288,
+        FirstJSDocTagNode = 278,
+        LastJSDocTagNode = 291,
     }
     enum NodeFlags {
         None = 0,
@@ -369,25 +378,20 @@ declare namespace ts {
         HasImplicitReturn = 128,
         HasExplicitReturn = 256,
         GlobalAugmentation = 512,
-        HasClassExtends = 1024,
-        HasDecorators = 2048,
-        HasParamDecorators = 4096,
-        HasAsyncFunctions = 8192,
-        HasJsxSpreadAttributes = 16384,
-        DisallowInContext = 32768,
-        YieldContext = 65536,
-        DecoratorContext = 131072,
-        AwaitContext = 262144,
-        ThisNodeHasError = 524288,
-        JavaScriptFile = 1048576,
-        ThisNodeOrAnySubNodesHasError = 2097152,
-        HasAggregatedChildData = 4194304,
+        HasAsyncFunctions = 1024,
+        DisallowInContext = 2048,
+        YieldContext = 4096,
+        DecoratorContext = 8192,
+        AwaitContext = 16384,
+        ThisNodeHasError = 32768,
+        JavaScriptFile = 65536,
+        ThisNodeOrAnySubNodesHasError = 131072,
+        HasAggregatedChildData = 262144,
         BlockScoped = 3,
         ReachabilityCheckFlags = 384,
-        EmitHelperFlags = 31744,
-        ReachabilityAndEmitFlags = 32128,
-        ContextFlags = 1540096,
-        TypeExcludesFlags = 327680,
+        ReachabilityAndEmitFlags = 1408,
+        ContextFlags = 96256,
+        TypeExcludesFlags = 20480,
     }
     enum ModifierFlags {
         None = 0,
@@ -407,6 +411,7 @@ declare namespace ts {
         ParameterPropertyModifier = 92,
         NonPublicAccessibilityModifier = 24,
         TypeScriptModifier = 2270,
+        ExportDefault = 513,
     }
     enum JsxFlags {
         None = 0,
@@ -437,12 +442,14 @@ declare namespace ts {
     type EqualsGreaterThanToken = Token<SyntaxKind.EqualsGreaterThanToken>;
     type EndOfFileToken = Token<SyntaxKind.EndOfFileToken>;
     type AtToken = Token<SyntaxKind.AtToken>;
+    type ReadonlyToken = Token<SyntaxKind.ReadonlyKeyword>;
     type Modifier = Token<SyntaxKind.AbstractKeyword> | Token<SyntaxKind.AsyncKeyword> | Token<SyntaxKind.ConstKeyword> | Token<SyntaxKind.DeclareKeyword> | Token<SyntaxKind.DefaultKeyword> | Token<SyntaxKind.ExportKeyword> | Token<SyntaxKind.PublicKeyword> | Token<SyntaxKind.PrivateKeyword> | Token<SyntaxKind.ProtectedKeyword> | Token<SyntaxKind.ReadonlyKeyword> | Token<SyntaxKind.StaticKeyword>;
     type ModifiersArray = NodeArray<Modifier>;
     interface Identifier extends PrimaryExpression {
         kind: SyntaxKind.Identifier;
         text: string;
         originalKeywordKind?: SyntaxKind;
+        isInJSDocNamespace?: boolean;
     }
     interface TransientIdentifier extends Identifier {
         resolvedSymbol: Symbol;
@@ -453,14 +460,14 @@ declare namespace ts {
         right: Identifier;
     }
     type EntityName = Identifier | QualifiedName;
-    type PropertyName = Identifier | LiteralExpression | ComputedPropertyName;
-    type DeclarationName = Identifier | LiteralExpression | ComputedPropertyName | BindingPattern;
+    type PropertyName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName;
+    type DeclarationName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName | BindingPattern;
     interface Declaration extends Node {
         _declarationBrand: any;
         name?: DeclarationName;
     }
     interface DeclarationStatement extends Declaration, Statement {
-        name?: Identifier | LiteralExpression;
+        name?: Identifier | StringLiteral | NumericLiteral;
     }
     interface ComputedPropertyName extends Node {
         kind: SyntaxKind.ComputedPropertyName;
@@ -533,7 +540,7 @@ declare namespace ts {
         _objectLiteralBrandBrand: any;
         name?: PropertyName;
     }
-    type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration;
+    type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration | SpreadAssignment;
     interface PropertyAssignment extends ObjectLiteralElement {
         kind: SyntaxKind.PropertyAssignment;
         name: PropertyName;
@@ -547,6 +554,10 @@ declare namespace ts {
         equalsToken?: Token<SyntaxKind.EqualsToken>;
         objectAssignmentInitializer?: Expression;
     }
+    interface SpreadAssignment extends ObjectLiteralElement {
+        kind: SyntaxKind.SpreadAssignment;
+        expression: Expression;
+    }
     interface VariableLikeDeclaration extends Declaration {
         propertyName?: PropertyName;
         dotDotDotToken?: DotDotDotToken;
@@ -558,18 +569,16 @@ declare namespace ts {
     interface PropertyLikeDeclaration extends Declaration {
         name: PropertyName;
     }
-    interface BindingPattern extends Node {
-        elements: NodeArray<BindingElement | ArrayBindingElement>;
-    }
-    interface ObjectBindingPattern extends BindingPattern {
+    interface ObjectBindingPattern extends Node {
         kind: SyntaxKind.ObjectBindingPattern;
         elements: NodeArray<BindingElement>;
     }
-    type ArrayBindingElement = BindingElement | OmittedExpression;
-    interface ArrayBindingPattern extends BindingPattern {
+    interface ArrayBindingPattern extends Node {
         kind: SyntaxKind.ArrayBindingPattern;
         elements: NodeArray<ArrayBindingElement>;
     }
+    type BindingPattern = ObjectBindingPattern | ArrayBindingPattern;
+    type ArrayBindingElement = BindingElement | OmittedExpression;
     /**
      * Several node kinds share function-like features such as a signature,
      * a name, and a body. These nodes should extend FunctionLikeDeclaration.
@@ -677,6 +686,23 @@ declare namespace ts {
         kind: SyntaxKind.ParenthesizedType;
         type: TypeNode;
     }
+    interface TypeOperatorNode extends TypeNode {
+        kind: SyntaxKind.TypeOperator;
+        operator: SyntaxKind.KeyOfKeyword;
+        type: TypeNode;
+    }
+    interface IndexedAccessTypeNode extends TypeNode {
+        kind: SyntaxKind.IndexedAccessType;
+        objectType: TypeNode;
+        indexType: TypeNode;
+    }
+    interface MappedTypeNode extends TypeNode, Declaration {
+        kind: SyntaxKind.MappedType;
+        readonlyToken?: ReadonlyToken;
+        typeParameter: TypeParameterDeclaration;
+        questionToken?: QuestionToken;
+        type?: TypeNode;
+    }
     interface LiteralTypeNode extends TypeNode {
         kind: SyntaxKind.LiteralType;
         literal: Expression;
@@ -709,9 +735,6 @@ declare namespace ts {
         operand: LeftHandSideExpression;
         operator: PostfixUnaryOperator;
     }
-    interface PostfixExpression extends UnaryExpression {
-        _postfixExpressionBrand: any;
-    }
     interface LeftHandSideExpression extends IncrementExpression {
         _leftHandSideExpressionBrand: any;
     }
@@ -780,6 +803,25 @@ declare namespace ts {
         operatorToken: BinaryOperatorToken;
         right: Expression;
     }
+    type AssignmentOperatorToken = Token<AssignmentOperator>;
+    interface AssignmentExpression<TOperator extends AssignmentOperatorToken> extends BinaryExpression {
+        left: LeftHandSideExpression;
+        operatorToken: TOperator;
+    }
+    interface ObjectDestructuringAssignment extends AssignmentExpression<EqualsToken> {
+        left: ObjectLiteralExpression;
+    }
+    interface ArrayDestructuringAssignment extends AssignmentExpression<EqualsToken> {
+        left: ArrayLiteralExpression;
+    }
+    type DestructuringAssignment = ObjectDestructuringAssignment | ArrayDestructuringAssignment;
+    type BindingOrAssignmentElement = VariableDeclaration | ParameterDeclaration | BindingElement | PropertyAssignment | ShorthandPropertyAssignment | SpreadAssignment | OmittedExpression | SpreadElement | ArrayLiteralExpression | ObjectLiteralExpression | AssignmentExpression<EqualsToken> | Identifier | PropertyAccessExpression | ElementAccessExpression;
+    type BindingOrAssignmentElementRestIndicator = DotDotDotToken | SpreadElement | SpreadAssignment;
+    type BindingOrAssignmentElementTarget = BindingOrAssignmentPattern | Expression;
+    type ObjectBindingOrAssignmentPattern = ObjectBindingPattern | ObjectLiteralExpression;
+    type ArrayBindingOrAssignmentPattern = ArrayBindingPattern | ArrayLiteralExpression;
+    type AssignmentPattern = ObjectLiteralExpression | ArrayLiteralExpression;
+    type BindingOrAssignmentPattern = ObjectBindingOrAssignmentPattern | ArrayBindingOrAssignmentPattern;
     interface ConditionalExpression extends Expression {
         kind: SyntaxKind.ConditionalExpression;
         condition: Expression;
@@ -846,8 +888,8 @@ declare namespace ts {
         kind: SyntaxKind.ArrayLiteralExpression;
         elements: NodeArray<Expression>;
     }
-    interface SpreadElementExpression extends Expression {
-        kind: SyntaxKind.SpreadElementExpression;
+    interface SpreadElement extends Expression {
+        kind: SyntaxKind.SpreadElement;
         expression: Expression;
     }
     /**
@@ -1140,13 +1182,17 @@ declare namespace ts {
     type ModuleName = Identifier | StringLiteral;
     interface ModuleDeclaration extends DeclarationStatement {
         kind: SyntaxKind.ModuleDeclaration;
-        name: Identifier | LiteralExpression;
-        body?: ModuleBlock | NamespaceDeclaration;
+        name: Identifier | StringLiteral;
+        body?: ModuleBlock | NamespaceDeclaration | JSDocNamespaceDeclaration | Identifier;
     }
     interface NamespaceDeclaration extends ModuleDeclaration {
         name: Identifier;
         body: ModuleBlock | NamespaceDeclaration;
     }
+    interface JSDocNamespaceDeclaration extends ModuleDeclaration {
+        name: Identifier;
+        body: JSDocNamespaceDeclaration | Identifier;
+    }
     interface ModuleBlock extends Node, Statement {
         kind: SyntaxKind.ModuleBlock;
         statements: NodeArray<Statement>;
@@ -1288,7 +1334,7 @@ declare namespace ts {
     type JSDocTypeReferencingNode = JSDocThisType | JSDocConstructorType | JSDocVariadicType | JSDocOptionalType | JSDocNullableType | JSDocNonNullableType;
     interface JSDocRecordMember extends PropertySignature {
         kind: SyntaxKind.JSDocRecordMember;
-        name: Identifier | LiteralExpression;
+        name: Identifier | StringLiteral | NumericLiteral;
         type?: JSDocType;
     }
     interface JSDoc extends Node {
@@ -1304,6 +1350,10 @@ declare namespace ts {
     interface JSDocUnknownTag extends JSDocTag {
         kind: SyntaxKind.JSDocTag;
     }
+    interface JSDocAugmentsTag extends JSDocTag {
+        kind: SyntaxKind.JSDocAugmentsTag;
+        typeExpression: JSDocTypeExpression;
+    }
     interface JSDocTemplateTag extends JSDocTag {
         kind: SyntaxKind.JSDocTemplateTag;
         typeParameters: NodeArray<TypeParameterDeclaration>;
@@ -1318,6 +1368,7 @@ declare namespace ts {
     }
     interface JSDocTypedefTag extends JSDocTag, Declaration {
         kind: SyntaxKind.JSDocTypedefTag;
+        fullName?: JSDocNamespaceDeclaration | Identifier;
         name?: Identifier;
         typeExpression?: JSDocTypeExpression;
         jsDocTypeLiteral?: JSDocTypeLiteral;
@@ -1551,6 +1602,7 @@ declare namespace ts {
         getJsxIntrinsicTagNames(): Symbol[];
         isOptionalParameter(node: ParameterDeclaration): boolean;
         getAmbientModules(): Symbol[];
+        tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined;
     }
     interface SymbolDisplayBuilder {
         buildTypeDisplay(type: Type, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
@@ -1571,6 +1623,7 @@ declare namespace ts {
         writeSpace(text: string): void;
         writeStringLiteral(text: string): void;
         writeParameter(text: string): void;
+        writeProperty(text: string): void;
         writeSymbol(text: string, symbol: Symbol): void;
         writeLine(): void;
         increaseIndent(): void;
@@ -1708,27 +1761,24 @@ declare namespace ts {
         Null = 4096,
         Never = 8192,
         TypeParameter = 16384,
-        Class = 32768,
-        Interface = 65536,
-        Reference = 131072,
-        Tuple = 262144,
-        Union = 524288,
-        Intersection = 1048576,
-        Anonymous = 2097152,
-        Instantiated = 4194304,
+        Object = 32768,
+        Union = 65536,
+        Intersection = 131072,
+        Index = 262144,
+        IndexedAccess = 524288,
         Literal = 480,
         StringOrNumberLiteral = 96,
         PossiblyFalsy = 7406,
-        StringLike = 34,
+        StringLike = 262178,
         NumberLike = 340,
         BooleanLike = 136,
         EnumLike = 272,
-        ObjectType = 2588672,
-        UnionOrIntersection = 1572864,
-        StructuredType = 4161536,
-        StructuredOrTypeParameter = 4177920,
-        Narrowable = 4178943,
-        NotUnionOrUnit = 2589185,
+        UnionOrIntersection = 196608,
+        StructuredType = 229376,
+        StructuredOrTypeParameter = 507904,
+        TypeVariable = 540672,
+        Narrowable = 1033215,
+        NotUnionOrUnit = 33281,
     }
     type DestructuringPattern = BindingPattern | ObjectLiteralExpression | ArrayLiteralExpression;
     interface Type {
@@ -1749,8 +1799,21 @@ declare namespace ts {
     interface EnumLiteralType extends LiteralType {
         baseType: EnumType & UnionType;
     }
+    enum ObjectFlags {
+        Class = 1,
+        Interface = 2,
+        Reference = 4,
+        Tuple = 8,
+        Anonymous = 16,
+        Mapped = 32,
+        Instantiated = 64,
+        ObjectLiteral = 128,
+        EvolvingArray = 256,
+        ObjectLiteralPatternWithComputedProperties = 512,
+        ClassOrInterface = 3,
+    }
     interface ObjectType extends Type {
-        isObjectLiteralPatternWithComputedProperties?: boolean;
+        objectFlags: ObjectFlags;
     }
     interface InterfaceType extends ObjectType {
         typeParameters: TypeParameter[];
@@ -1778,9 +1841,24 @@ declare namespace ts {
     }
     interface IntersectionType extends UnionOrIntersectionType {
     }
-    interface TypeParameter extends Type {
+    type StructuredType = ObjectType | UnionType | IntersectionType;
+    interface EvolvingArrayType extends ObjectType {
+        elementType: Type;
+        finalArrayType?: Type;
+    }
+    interface TypeVariable extends Type {
+    }
+    interface TypeParameter extends TypeVariable {
         constraint: Type;
     }
+    interface IndexedAccessType extends TypeVariable {
+        objectType: Type;
+        indexType: Type;
+        constraint?: Type;
+    }
+    interface IndexType extends Type {
+        type: TypeVariable | UnionOrIntersectionType;
+    }
     enum SignatureKind {
         Call = 0,
         Construct = 1,
@@ -1799,6 +1877,11 @@ declare namespace ts {
         isReadonly: boolean;
         declaration?: SignatureDeclaration;
     }
+    interface FileExtensionInfo {
+        extension: string;
+        scriptKind: ScriptKind;
+        isMixedContent: boolean;
+    }
     interface DiagnosticMessage {
         key: string;
         category: DiagnosticCategory;
@@ -1882,6 +1965,7 @@ declare namespace ts {
         preserveConstEnums?: boolean;
         project?: string;
         reactNamespace?: string;
+        jsxFactory?: string;
         removeComments?: boolean;
         rootDir?: string;
         rootDirs?: string[];
@@ -1895,12 +1979,13 @@ declare namespace ts {
         target?: ScriptTarget;
         traceResolution?: boolean;
         types?: string[];
-        /** Paths used to used to compute primary types search locations */
+        /** Paths used to compute primary types search locations */
         typeRoots?: string[];
         [option: string]: CompilerOptionsValue | undefined;
     }
-    interface TypingOptions {
+    interface TypeAcquisition {
         enableAutoDiscovery?: boolean;
+        enable?: boolean;
         include?: string[];
         exclude?: string[];
         [option: string]: string[] | boolean | undefined;
@@ -1910,8 +1995,9 @@ declare namespace ts {
         projectRootPath: string;
         safeListPath: string;
         packageNameToTypingLocation: Map<string>;
-        typingOptions: TypingOptions;
+        typeAcquisition: TypeAcquisition;
         compilerOptions: CompilerOptions;
+        unresolvedImports: ReadonlyArray<string>;
     }
     enum ModuleKind {
         None = 0,
@@ -1947,15 +2033,17 @@ declare namespace ts {
         ES2015 = 2,
         ES2016 = 3,
         ES2017 = 4,
-        Latest = 4,
+        ESNext = 5,
+        Latest = 5,
     }
     enum LanguageVariant {
         Standard = 0,
         JSX = 1,
     }
+    /** Either a parsed command line or a parsed tsconfig.json */
     interface ParsedCommandLine {
         options: CompilerOptions;
-        typingOptions?: TypingOptions;
+        typeAcquisition?: TypeAcquisition;
         fileNames: string[];
         raw?: any;
         errors: Diagnostic[];
@@ -1979,12 +2067,45 @@ declare namespace ts {
         getCurrentDirectory?(): string;
         getDirectories?(path: string): string[];
     }
+    /**
+     * Represents the result of module resolution.
+     * Module resolution will pick up tsx/jsx/js files even if '--jsx' and '--allowJs' are turned off.
+     * The Program will then filter results based on these flags.
+     *
+     * Prefer to return a `ResolvedModuleFull` so that the file type does not have to be inferred.
+     */
     interface ResolvedModule {
+        /** Path of the file the module was resolved to. */
         resolvedFileName: string;
+        /**
+         * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be a proper external module:
+         * - be a .d.ts file
+         * - use top level imports\exports
+         * - don't use tripleslash references
+         */
         isExternalLibraryImport?: boolean;
     }
+    /**
+     * ResolvedModule with an explicitly provided `extension` property.
+     * Prefer this over `ResolvedModule`.
+     */
+    interface ResolvedModuleFull extends ResolvedModule {
+        /**
+         * Extension of resolvedFileName. This must match what's at the end of resolvedFileName.
+         * This is optional for backwards-compatibility, but will be added if not provided.
+         */
+        extension: Extension;
+    }
+    enum Extension {
+        Ts = 0,
+        Tsx = 1,
+        Dts = 2,
+        Js = 3,
+        Jsx = 4,
+        LastTypeScriptExtension = 2,
+    }
     interface ResolvedModuleWithFailedLookupLocations {
-        resolvedModule: ResolvedModule;
+        resolvedModule: ResolvedModuleFull | undefined;
         failedLookupLocations: string[];
     }
     interface ResolvedTypeReferenceDirective {
@@ -2026,6 +2147,10 @@ declare namespace ts {
         _children: Node[];
     }
 }
+declare namespace ts {
+    /** The version of the TypeScript compiler release */
+    const version = "2.2.0";
+}
 declare namespace ts {
     type FileWatcherCallback = (fileName: string, removed?: boolean) => void;
     type DirectoryWatcherCallback = (fileName: string) => void;
@@ -2042,7 +2167,11 @@ declare namespace ts {
         readFile(path: string, encoding?: string): string;
         getFileSize?(path: string): number;
         writeFile(path: string, data: string, writeByteOrderMark?: boolean): void;
-        watchFile?(path: string, callback: FileWatcherCallback): FileWatcher;
+        /**
+         * @pollingInterval - this parameter is used in polling-based watchers and ignored in watchers that
+         * use native OS file watching
+         */
+        watchFile?(path: string, callback: FileWatcherCallback, pollingInterval?: number): FileWatcher;
         watchDirectory?(path: string, callback: DirectoryWatcherCallback, recursive?: boolean): FileWatcher;
         resolvePath(path: string): string;
         fileExists(path: string): boolean;
@@ -2057,6 +2186,8 @@ declare namespace ts {
         getMemoryUsage?(): number;
         exit(exitCode?: number): void;
         realpath?(path: string): string;
+        setTimeout?(callback: (...args: any[]) => void, ms: number, ...args: any[]): any;
+        clearTimeout?(timeoutId: any): void;
     }
     interface FileWatcher {
         close(): void;
@@ -2151,18 +2282,30 @@ declare namespace ts {
      */
     function collapseTextChangeRangesAcrossMultipleVersions(changes: TextChangeRange[]): TextChangeRange;
     function getTypeParameterOwner(d: Declaration): Declaration;
-    function isParameterPropertyDeclaration(node: ParameterDeclaration): boolean;
+    function isParameterPropertyDeclaration(node: Node): boolean;
     function getCombinedModifierFlags(node: Node): ModifierFlags;
     function getCombinedNodeFlags(node: Node): NodeFlags;
+    /**
+      * Checks to see if the locale is in the appropriate format,
+      * and if it is, attempts to set the appropriate language.
+      */
+    function validateLocaleAndSetLanguage(locale: string, sys: {
+        getExecutingFilePath(): string;
+        resolvePath(path: string): string;
+        fileExists(fileName: string): boolean;
+        readFile(fileName: string): string;
+    }, errors?: Diagnostic[]): void;
 }
 declare namespace ts {
     function createNode(kind: SyntaxKind, pos?: number, end?: number): Node;
     function forEachChild<T>(node: Node, cbNode: (node: Node) => T, cbNodeArray?: (nodes: Node[]) => T): T;
     function createSourceFile(fileName: string, sourceText: string, languageVersion: ScriptTarget, setParentNodes?: boolean, scriptKind?: ScriptKind): SourceFile;
+    function parseIsolatedEntityName(text: string, languageVersion: ScriptTarget): EntityName;
     function isExternalModule(file: SourceFile): boolean;
     function updateSourceFile(sourceFile: SourceFile, newText: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;
 }
 declare namespace ts {
+    function moduleHasNonRelativeName(moduleName: string): boolean;
     function getEffectiveTypeRoots(options: CompilerOptions, host: {
         directoryExists?: (directoryName: string) => boolean;
         getCurrentDirectory?: () => string;
@@ -2172,7 +2315,7 @@ declare namespace ts {
      * This is possible in case if resolution is performed for directives specified via 'types' parameter. In this case initial path for secondary lookups
      * is assumed to be the same as root directory of the project.
      */
-    function resolveTypeReferenceDirective(typeReferenceDirectiveName: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost): ResolvedTypeReferenceDirectiveWithFailedLookupLocations;
+    function resolveTypeReferenceDirective(typeReferenceDirectiveName: string, containingFile: string | undefined, options: CompilerOptions, host: ModuleResolutionHost): ResolvedTypeReferenceDirectiveWithFailedLookupLocations;
     /**
       * Given a set of options, returns the set of type directive names
       *   that should be included for this program automatically.
@@ -2187,8 +2330,6 @@ declare namespace ts {
     function classicNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations;
 }
 declare namespace ts {
-    /** The version of the TypeScript compiler release */
-    const version = "2.1.0";
     function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string;
     function resolveTripleslashReference(moduleName: string, containingFile: string): string;
     function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;
@@ -2203,6 +2344,7 @@ declare namespace ts {
     function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost, oldProgram?: Program): Program;
 }
 declare namespace ts {
+    function parseCommandLine(commandLine: string[], readFile?: (path: string) => string): ParsedCommandLine;
     /**
       * Read tsconfig.json file
       * @param fileName The path to the config file
@@ -2227,14 +2369,14 @@ declare namespace ts {
       * @param basePath A root directory to resolve relative path entries in the config
       *    file to. e.g. outDir
       */
-    function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions?: CompilerOptions, configFileName?: string, resolutionStack?: Path[]): ParsedCommandLine;
+    function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions?: CompilerOptions, configFileName?: string, resolutionStack?: Path[], extraFileExtensions?: FileExtensionInfo[]): ParsedCommandLine;
     function convertCompileOnSaveOptionFromJson(jsonOption: any, basePath: string, errors: Diagnostic[]): boolean;
     function convertCompilerOptionsFromJson(jsonOptions: any, basePath: string, configFileName?: string): {
         options: CompilerOptions;
         errors: Diagnostic[];
     };
-    function convertTypingOptionsFromJson(jsonOptions: any, basePath: string, configFileName?: string): {
-        options: TypingOptions;
+    function convertTypeAcquisitionFromJson(jsonOptions: any, basePath: string, configFileName?: string): {
+        options: TypeAcquisition;
         errors: Diagnostic[];
     };
 }
@@ -2283,6 +2425,7 @@ declare namespace ts {
     }
     interface SourceFile {
         getLineAndCharacterOfPosition(pos: number): LineAndCharacter;
+        getLineEndOfPosition(pos: number): number;
         getLineStarts(): number[];
         getPositionOfLineAndCharacter(line: number, character: number): number;
         update(newText: string, textChangeRange: TextChangeRange): SourceFile;

netci.groovy

@@ -5,7 +5,7 @@ import jobs.generation.Utilities;
 def project = GithubProject
 def branch = GithubBranchName
 
-def nodeVersions = ['stable', '4']
+def nodeVersions = ['stable', '6', '4']
 
 nodeVersions.each { nodeVer ->
 

package.json

@@ -2,7 +2,7 @@
     "name": "typescript",
     "author": "Microsoft Corp.",
     "homepage": "http://typescriptlang.org/",
-    "version": "2.1.0",
+    "version": "2.2.0",
     "license": "Apache-2.0",
     "description": "TypeScript is a language for application scale JavaScript development",
     "keywords": [
@@ -26,7 +26,7 @@
         "tsserver": "./bin/tsserver"
     },
     "engines": {
-        "node": ">=0.8.0"
+        "node": ">=4.2.0"
     },
     "devDependencies": {
         "@types/browserify": "latest",
@@ -75,8 +75,7 @@
         "through2": "latest",
         "travis-fold": "latest",
         "ts-node": "latest",
-        "tsd": "latest",
-        "tslint": "4.0.0-dev.0",
+        "tslint": "next",
         "typescript": "next"
     },
     "scripts": {

scripts/parallel-lint.js

@@ -1,26 +1,29 @@
-var Linter = require("tslint");
+var tslint = require("tslint");
 var fs = require("fs");
 
 function getLinterOptions() {
     return {
-        configuration: require("../tslint.json"),
         formatter: "prose",
         formattersDirectory: undefined,
         rulesDirectory: "built/local/tslint"
     };
 }
-
-function lintFileContents(options, path, contents) {
-    var ll = new Linter(path, contents, options);
-    return ll.lint();
+function getLinterConfiguration() {
+    return require("../tslint.json");
 }
 
-function lintFileAsync(options, path, cb) {
+function lintFileContents(options, configuration, path, contents) {
+    var ll = new tslint.Linter(options);
+    ll.lint(path, contents, configuration);
+    return ll.getResult();
+}
+
+function lintFileAsync(options, configuration, path, cb) {
     fs.readFile(path, "utf8", function (err, contents) {
         if (err) {
             return cb(err);
         }
-        var result = lintFileContents(options, path, contents);
+        var result = lintFileContents(options, configuration, path, contents);
         cb(undefined, result);
     });
 }
@@ -30,7 +33,8 @@ process.on("message", function (data) {
         case "file":
             var target = data.name;
             var lintOptions = getLinterOptions();
-            lintFileAsync(lintOptions, target, function (err, result) {
+            var lintConfiguration = getLinterConfiguration();
+            lintFileAsync(lintOptions, lintConfiguration, target, function (err, result) {
                 if (err) {
                     process.send({ kind: "error", error: err.toString() });
                     return;

scripts/tslint/booleanTriviaRule.ts

@@ -1,4 +1,4 @@
-import * as Lint from "tslint/lib/lint";
+import * as Lint from "tslint/lib";
 import * as ts from "typescript";
 
 export class Rule extends Lint.Rules.AbstractRule {

scripts/tslint/nextLineRule.ts

@@ -1,4 +1,4 @@
-import * as Lint from "tslint/lib/lint";
+import * as Lint from "tslint/lib";
 import * as ts from "typescript";
 
 const OPTION_CATCH = "check-catch";

scripts/tslint/noInOperatorRule.ts

@@ -1,4 +1,4 @@
-import * as Lint from "tslint/lib/lint";
+import * as Lint from "tslint/lib";
 import * as ts from "typescript";
 
 

scripts/tslint/noIncrementDecrementRule.ts

@@ -1,4 +1,4 @@
-import * as Lint from "tslint/lib/lint";
+import * as Lint from "tslint/lib";
 import * as ts from "typescript";
 
 

scripts/tslint/noTypeAssertionWhitespaceRule.ts

@@ -1,4 +1,4 @@
-import * as Lint from "tslint/lib/lint";
+import * as Lint from "tslint/lib";
 import * as ts from "typescript";
 
 

scripts/tslint/objectLiteralSurroundingSpaceRule.ts

@@ -1,4 +1,4 @@
-import * as Lint from "tslint/lib/lint";
+import * as Lint from "tslint/lib";
 import * as ts from "typescript";
 
 

scripts/tslint/preferConstRule.ts

@@ -1,204 +0,0 @@
-import * as Lint from "tslint/lib/lint";
-import * as ts from "typescript";
-
-export class Rule extends Lint.Rules.AbstractRule {
-    public static FAILURE_STRING_FACTORY = (identifier: string) => `Identifier '${identifier}' never appears on the LHS of an assignment - use const instead of let for its declaration.`;
-
-    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
-        return this.applyWithWalker(new PreferConstWalker(sourceFile, this.getOptions()));
-    }
-}
-
-function isLet(node: ts.Node) {
-    return !!(ts.getCombinedNodeFlags(node) & ts.NodeFlags.Let);
-}
-
-function isExported(node: ts.Node) {
-    return !!(ts.getCombinedModifierFlags(node) & ts.ModifierFlags.Export);
-}
-
-function isAssignmentOperator(token: ts.SyntaxKind): boolean {
-    return token >= ts.SyntaxKind.FirstAssignment && token <= ts.SyntaxKind.LastAssignment;
-}
-
-function isBindingLiteralExpression(node: ts.Node): node is (ts.ArrayLiteralExpression | ts.ObjectLiteralExpression) {
-    return (!!node) && (node.kind === ts.SyntaxKind.ObjectLiteralExpression || node.kind === ts.SyntaxKind.ArrayLiteralExpression);
-}
-
-interface DeclarationUsages {
-    declaration: ts.VariableDeclaration;
-    usages: number;
-}
-
-class PreferConstWalker extends Lint.RuleWalker {
-    private inScopeLetDeclarations: ts.MapLike<DeclarationUsages>[] = [];
-    private errors: Lint.RuleFailure[] = [];
-    private markAssignment(identifier: ts.Identifier) {
-        const name = identifier.text;
-        for (let i = this.inScopeLetDeclarations.length - 1; i >= 0; i--) {
-            const declarations = this.inScopeLetDeclarations[i];
-            if (declarations[name]) {
-                declarations[name].usages++;
-                break;
-            }
-        }
-    }
-
-    visitSourceFile(node: ts.SourceFile) {
-        super.visitSourceFile(node);
-        // Sort errors by position because tslint doesn't
-        this.errors.sort((a, b) => a.getStartPosition().getPosition() - b.getStartPosition().getPosition()).forEach(e => this.addFailure(e));
-    }
-
-    visitBinaryExpression(node: ts.BinaryExpression) {
-        if (isAssignmentOperator(node.operatorToken.kind)) {
-            this.visitLeftHandSideExpression(node.left);
-        }
-        super.visitBinaryExpression(node);
-    }
-
-    private visitLeftHandSideExpression(node: ts.Expression) {
-        while (node.kind === ts.SyntaxKind.ParenthesizedExpression) {
-            node = (node as ts.ParenthesizedExpression).expression;
-        }
-        if (node.kind === ts.SyntaxKind.Identifier) {
-            this.markAssignment(node as ts.Identifier);
-        }
-        else if (isBindingLiteralExpression(node)) {
-            this.visitBindingLiteralExpression(node as (ts.ArrayLiteralExpression | ts.ObjectLiteralExpression));
-        }
-    }
-
-    private visitBindingLiteralExpression(node: ts.ArrayLiteralExpression | ts.ObjectLiteralExpression) {
-        if (node.kind === ts.SyntaxKind.ObjectLiteralExpression) {
-            const pattern = node as ts.ObjectLiteralExpression;
-            for (const element of pattern.properties) {
-                const kind = element.kind;
-
-                if (kind === ts.SyntaxKind.ShorthandPropertyAssignment) {
-                    this.markAssignment((element as ts.ShorthandPropertyAssignment).name);
-                }
-                else if (kind === ts.SyntaxKind.PropertyAssignment) {
-                    this.visitLeftHandSideExpression((element as ts.PropertyAssignment).initializer);
-                }
-            }
-        }
-        else if (node.kind === ts.SyntaxKind.ArrayLiteralExpression) {
-            const pattern = node as ts.ArrayLiteralExpression;
-            for (const element of pattern.elements) {
-                this.visitLeftHandSideExpression(element);
-            }
-        }
-    }
-
-    private visitBindingPatternIdentifiers(pattern: ts.BindingPattern) {
-        for (const element of pattern.elements) {
-            if (element.kind !== ts.SyntaxKind.BindingElement) {
-                continue;
-            }
-
-            const name = (<ts.BindingElement>element).name;
-            if (name.kind === ts.SyntaxKind.Identifier) {
-                this.markAssignment(name as ts.Identifier);
-            }
-            else {
-                this.visitBindingPatternIdentifiers(name as ts.BindingPattern);
-            }
-        }
-    }
-
-    visitPrefixUnaryExpression(node: ts.PrefixUnaryExpression) {
-        this.visitAnyUnaryExpression(node);
-        super.visitPrefixUnaryExpression(node);
-    }
-
-    visitPostfixUnaryExpression(node: ts.PostfixUnaryExpression) {
-        this.visitAnyUnaryExpression(node);
-        super.visitPostfixUnaryExpression(node);
-    }
-
-    private visitAnyUnaryExpression(node: ts.PrefixUnaryExpression | ts.PostfixUnaryExpression) {
-        if (node.operator === ts.SyntaxKind.PlusPlusToken || node.operator === ts.SyntaxKind.MinusMinusToken) {
-            this.visitLeftHandSideExpression(node.operand);
-        }
-    }
-
-    visitModuleDeclaration(node: ts.ModuleDeclaration) {
-        if (node.body.kind === ts.SyntaxKind.ModuleBlock) {
-            // For some reason module blocks are left out of the visit block traversal
-            this.visitBlock(node.body as any as ts.Block);
-        }
-        super.visitModuleDeclaration(node);
-    }
-
-    visitForOfStatement(node: ts.ForOfStatement) {
-        this.visitAnyForStatement(node);
-        super.visitForOfStatement(node);
-        this.popDeclarations();
-    }
-
-    visitForInStatement(node: ts.ForInStatement) {
-        this.visitAnyForStatement(node);
-        super.visitForInStatement(node);
-        this.popDeclarations();
-    }
-
-    private visitAnyForStatement(node: ts.ForOfStatement | ts.ForInStatement) {
-        const names: ts.MapLike<DeclarationUsages> = {};
-        if (isLet(node.initializer)) {
-            if (node.initializer.kind === ts.SyntaxKind.VariableDeclarationList) {
-                this.collectLetIdentifiers(node.initializer as ts.VariableDeclarationList, names);
-            }
-        }
-        this.inScopeLetDeclarations.push(names);
-    }
-
-    private popDeclarations() {
-        const completed = this.inScopeLetDeclarations.pop();
-        for (const name in completed) {
-            if (Object.hasOwnProperty.call(completed, name)) {
-                const element = completed[name];
-                if (element.usages === 0) {
-                    this.errors.push(this.createFailure(element.declaration.getStart(this.getSourceFile()), element.declaration.getWidth(this.getSourceFile()), Rule.FAILURE_STRING_FACTORY(name)));
-                }
-            }
-        }
-    }
-
-    visitBlock(node: ts.Block) {
-        const names: ts.MapLike<DeclarationUsages> = {};
-        for (const statement of node.statements) {
-            if (statement.kind === ts.SyntaxKind.VariableStatement) {
-                this.collectLetIdentifiers((statement as ts.VariableStatement).declarationList, names);
-            }
-        }
-        this.inScopeLetDeclarations.push(names);
-        super.visitBlock(node);
-        this.popDeclarations();
-    }
-
-    private collectLetIdentifiers(list: ts.VariableDeclarationList, ret: ts.MapLike<DeclarationUsages>) {
-        for (const node of list.declarations) {
-            if (isLet(node) && !isExported(node)) {
-                this.collectNameIdentifiers(node, node.name, ret);
-            }
-        }
-    }
-
-    private collectNameIdentifiers(declaration: ts.VariableDeclaration, node: ts.Identifier | ts.BindingPattern, table: ts.MapLike<DeclarationUsages>) {
-        if (node.kind === ts.SyntaxKind.Identifier) {
-            table[(node as ts.Identifier).text] = { declaration, usages: 0 };
-        }
-        else {
-            this.collectBindingPatternIdentifiers(declaration, node as ts.BindingPattern, table);
-        }
-    }
-
-    private collectBindingPatternIdentifiers(value: ts.VariableDeclaration, pattern: ts.BindingPattern, table: ts.MapLike<DeclarationUsages>) {
-        for (const element of pattern.elements) {
-            if (element.kind === ts.SyntaxKind.BindingElement) {
-                this.collectNameIdentifiers(value, (<ts.BindingElement>element).name, table);
-            }
-        }
-    }
-}

scripts/tslint/typeOperatorSpacingRule.ts

@@ -1,4 +1,4 @@
-import * as Lint from "tslint/lib/lint";
+import * as Lint from "tslint/lib";
 import * as ts from "typescript";
 
 

src/compiler/binder.ts

@@ -234,8 +234,8 @@ namespace ts {
                 if (node.name.kind === SyntaxKind.ComputedPropertyName) {
                     const nameExpression = (<ComputedPropertyName>node.name).expression;
                     // treat computed property names where expression is string/numeric literal as just string/numeric literal
-                    if (isStringOrNumericLiteral(nameExpression.kind)) {
-                        return (<LiteralExpression>nameExpression).text;
+                    if (isStringOrNumericLiteral(nameExpression)) {
+                        return nameExpression.text;
                     }
 
                     Debug.assert(isWellKnownSymbolSyntactically(nameExpression));
@@ -283,8 +283,8 @@ namespace ts {
                     // Parameters with names are handled at the top of this function.  Parameters
                     // without names can only come from JSDocFunctionTypes.
                     Debug.assert(node.parent.kind === SyntaxKind.JSDocFunctionType);
-                    let functionType = <JSDocFunctionType>node.parent;
-                    let index = indexOf(functionType.parameters, node);
+                    const functionType = <JSDocFunctionType>node.parent;
+                    const index = indexOf(functionType.parameters, node);
                     return "arg" + index;
                 case SyntaxKind.JSDocTypedefTag:
                     const parentNode = node.parent && node.parent.parent;
@@ -518,7 +518,6 @@ namespace ts {
                 hasExplicitReturn = false;
                 bindChildren(node);
                 // Reset all reachability check related flags on node (for incremental scenarios)
-                // Reset all emit helper flags on node (for incremental scenarios)
                 node.flags &= ~NodeFlags.ReachabilityAndEmitFlags;
                 if (!(currentFlow.flags & FlowFlags.Unreachable) && containerFlags & ContainerFlags.IsFunctionLike && nodeIsPresent((<FunctionLikeDeclaration>node).body)) {
                     node.flags |= NodeFlags.HasImplicitReturn;
@@ -570,15 +569,40 @@ namespace ts {
             }
         }
 
+        function bindEach(nodes: NodeArray<Node>) {
+            if (nodes === undefined) {
+                return;
+            }
+
+            if (skipTransformFlagAggregation) {
+                forEach(nodes, bind);
+            }
+            else {
+                const savedSubtreeTransformFlags = subtreeTransformFlags;
+                subtreeTransformFlags = TransformFlags.None;
+                let nodeArrayFlags = TransformFlags.None;
+                for (const node of nodes) {
+                    bind(node);
+                    nodeArrayFlags |= node.transformFlags & ~TransformFlags.HasComputedFlags;
+                }
+                nodes.transformFlags = nodeArrayFlags | TransformFlags.HasComputedFlags;
+                subtreeTransformFlags |= savedSubtreeTransformFlags;
+            }
+        }
+
+        function bindEachChild(node: Node) {
+            forEachChild(node, bind, bindEach);
+        }
+
         function bindChildrenWorker(node: Node): void {
             // Binding of JsDocComment should be done before the current block scope container changes.
             // because the scope of JsDocComment should not be affected by whether the current node is a
             // container or not.
-            if (isInJavaScriptFile(node) && node.jsDocComments) {
-                forEach(node.jsDocComments, bind);
+            if (isInJavaScriptFile(node) && node.jsDoc) {
+                forEach(node.jsDoc, bind);
             }
             if (checkUnreachable(node)) {
-                forEachChild(node, bind);
+                bindEachChild(node);
                 return;
             }
             switch (node.kind) {
@@ -643,7 +667,7 @@ namespace ts {
                     bindCallExpressionFlow(<CallExpression>node);
                     break;
                 default:
-                    forEachChild(node, bind);
+                    bindEachChild(node);
                     break;
             }
         }
@@ -976,7 +1000,7 @@ namespace ts {
             return undefined;
         }
 
-        function bindbreakOrContinueFlow(node: BreakOrContinueStatement, breakTarget: FlowLabel, continueTarget: FlowLabel) {
+        function bindBreakOrContinueFlow(node: BreakOrContinueStatement, breakTarget: FlowLabel, continueTarget: FlowLabel) {
             const flowLabel = node.kind === SyntaxKind.BreakStatement ? breakTarget : continueTarget;
             if (flowLabel) {
                 addAntecedent(flowLabel, currentFlow);
@@ -990,11 +1014,11 @@ namespace ts {
                 const activeLabel = findActiveLabel(node.label.text);
                 if (activeLabel) {
                     activeLabel.referenced = true;
-                    bindbreakOrContinueFlow(node, activeLabel.breakTarget, activeLabel.continueTarget);
+                    bindBreakOrContinueFlow(node, activeLabel.breakTarget, activeLabel.continueTarget);
                 }
             }
             else {
-                bindbreakOrContinueFlow(node, currentBreakTarget, currentContinueTarget);
+                bindBreakOrContinueFlow(node, currentBreakTarget, currentContinueTarget);
             }
         }
 
@@ -1062,6 +1086,8 @@ namespace ts {
         }
 
         function bindCaseBlock(node: CaseBlock): void {
+            const savedSubtreeTransformFlags = subtreeTransformFlags;
+            subtreeTransformFlags = 0;
             const clauses = node.clauses;
             let fallthroughFlow = unreachableFlow;
             for (let i = 0; i < clauses.length; i++) {
@@ -1081,6 +1107,8 @@ namespace ts {
                     errorOnFirstToken(clause, Diagnostics.Fallthrough_case_in_switch);
                 }
             }
+            clauses.transformFlags = subtreeTransformFlags | TransformFlags.HasComputedFlags;
+            subtreeTransformFlags |= savedSubtreeTransformFlags;
         }
 
         function bindCaseClause(node: CaseClause): void {
@@ -1088,7 +1116,7 @@ namespace ts {
             currentFlow = preSwitchCaseFlow;
             bind(node.expression);
             currentFlow = saveCurrentFlow;
-            forEach(node.statements, bind);
+            bindEach(node.statements);
         }
 
         function pushActiveLabel(name: string, breakTarget: FlowLabel, continueTarget: FlowLabel): ActiveLabel {
@@ -1139,8 +1167,8 @@ namespace ts {
             }
             else if (node.kind === SyntaxKind.ArrayLiteralExpression) {
                 for (const e of (<ArrayLiteralExpression>node).elements) {
-                    if (e.kind === SyntaxKind.SpreadElementExpression) {
-                        bindAssignmentTargetFlow((<SpreadElementExpression>e).expression);
+                    if (e.kind === SyntaxKind.SpreadElement) {
+                        bindAssignmentTargetFlow((<SpreadElement>e).expression);
                     }
                     else {
                         bindDestructuringTargetFlow(e);
@@ -1155,6 +1183,9 @@ namespace ts {
                     else if (p.kind === SyntaxKind.ShorthandPropertyAssignment) {
                         bindAssignmentTargetFlow((<ShorthandPropertyAssignment>p).name);
                     }
+                    else if (p.kind === SyntaxKind.SpreadAssignment) {
+                        bindAssignmentTargetFlow((<SpreadAssignment>p).expression);
+                    }
                 }
             }
         }
@@ -1177,12 +1208,12 @@ namespace ts {
                 const saveTrueTarget = currentTrueTarget;
                 currentTrueTarget = currentFalseTarget;
                 currentFalseTarget = saveTrueTarget;
-                forEachChild(node, bind);
+                bindEachChild(node);
                 currentFalseTarget = currentTrueTarget;
                 currentTrueTarget = saveTrueTarget;
             }
             else {
-                forEachChild(node, bind);
+                bindEachChild(node);
                 if (node.operator === SyntaxKind.PlusPlusToken || node.operator === SyntaxKind.MinusMinusToken) {
                     bindAssignmentTargetFlow(node.operand);
                 }
@@ -1190,7 +1221,7 @@ namespace ts {
         }
 
         function bindPostfixUnaryExpressionFlow(node: PostfixUnaryExpression) {
-            forEachChild(node, bind);
+            bindEachChild(node);
             if (node.operator === SyntaxKind.PlusPlusToken || node.operator === SyntaxKind.MinusMinusToken) {
                 bindAssignmentTargetFlow(node.operand);
             }
@@ -1209,7 +1240,7 @@ namespace ts {
                 }
             }
             else {
-                forEachChild(node, bind);
+                bindEachChild(node);
                 if (isAssignmentOperator(operator) && !isAssignmentTarget(node)) {
                     bindAssignmentTargetFlow(node.left);
                     if (operator === SyntaxKind.EqualsToken && node.left.kind === SyntaxKind.ElementAccessExpression) {
@@ -1223,7 +1254,7 @@ namespace ts {
         }
 
         function bindDeleteExpressionFlow(node: DeleteExpression) {
-            forEachChild(node, bind);
+            bindEachChild(node);
             if (node.expression.kind === SyntaxKind.PropertyAccessExpression) {
                 bindAssignmentTargetFlow(node.expression);
             }
@@ -1248,7 +1279,7 @@ namespace ts {
         function bindInitializedVariableFlow(node: VariableDeclaration | ArrayBindingElement) {
             const name = !isOmittedExpression(node) ? node.name : undefined;
             if (isBindingPattern(name)) {
-                for (const child of name.elements) {
+                for (const child of <ArrayBindingElement[]>name.elements) {
                     bindInitializedVariableFlow(child);
                 }
             }
@@ -1258,7 +1289,7 @@ namespace ts {
         }
 
         function bindVariableDeclarationFlow(node: VariableDeclaration) {
-            forEachChild(node, bind);
+            bindEachChild(node);
             if (node.initializer || node.parent.parent.kind === SyntaxKind.ForInStatement || node.parent.parent.kind === SyntaxKind.ForOfStatement) {
                 bindInitializedVariableFlow(node);
             }
@@ -1273,12 +1304,12 @@ namespace ts {
                 expr = (<ParenthesizedExpression>expr).expression;
             }
             if (expr.kind === SyntaxKind.FunctionExpression || expr.kind === SyntaxKind.ArrowFunction) {
-                forEach(node.typeArguments, bind);
-                forEach(node.arguments, bind);
+                bindEach(node.typeArguments);
+                bindEach(node.arguments);
                 bind(node.expression);
             }
             else {
-                forEachChild(node, bind);
+                bindEachChild(node);
             }
             if (node.expression.kind === SyntaxKind.PropertyAccessExpression) {
                 const propertyAccess = <PropertyAccessExpression>node.expression;
@@ -1305,6 +1336,7 @@ namespace ts {
                 case SyntaxKind.JSDocFunctionType:
                 case SyntaxKind.ModuleDeclaration:
                 case SyntaxKind.TypeAliasDeclaration:
+                case SyntaxKind.MappedType:
                     return ContainerFlags.IsContainer | ContainerFlags.HasLocals;
 
                 case SyntaxKind.SourceFile:
@@ -1424,6 +1456,7 @@ namespace ts {
                 case SyntaxKind.ArrowFunction:
                 case SyntaxKind.JSDocFunctionType:
                 case SyntaxKind.TypeAliasDeclaration:
+                case SyntaxKind.MappedType:
                     // All the children of these container types are never visible through another
                     // symbol (i.e. through another symbol's 'exports' or 'members').  Instead,
                     // they're only accessed 'lexically' (i.e. from code that exists underneath
@@ -1550,7 +1583,7 @@ namespace ts {
                 const seen = createMap<ElementKind>();
 
                 for (const prop of node.properties) {
-                    if (prop.name.kind !== SyntaxKind.Identifier) {
+                    if (prop.kind === SyntaxKind.SpreadAssignment || prop.name.kind !== SyntaxKind.Identifier) {
                         continue;
                     }
 
@@ -1929,8 +1962,20 @@ namespace ts {
                 case SyntaxKind.EnumMember:
                     return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.EnumMember, SymbolFlags.EnumMemberExcludes);
 
+                case SyntaxKind.SpreadAssignment:
                 case SyntaxKind.JsxSpreadAttribute:
-                    emitFlags |= NodeFlags.HasJsxSpreadAttributes;
+                    let root = container;
+                    let hasRest = false;
+                    while (root.parent) {
+                        if (root.kind === SyntaxKind.ObjectLiteralExpression &&
+                            root.parent.kind === SyntaxKind.BinaryExpression &&
+                            (root.parent as BinaryExpression).operatorToken.kind === SyntaxKind.EqualsToken &&
+                            (root.parent as BinaryExpression).left === root) {
+                            hasRest = true;
+                            break;
+                        }
+                        root = root.parent;
+                    }
                     return;
 
                 case SyntaxKind.CallSignature:
@@ -1958,9 +2003,10 @@ namespace ts {
                 case SyntaxKind.JSDocFunctionType:
                     return bindFunctionOrConstructorType(<SignatureDeclaration>node);
                 case SyntaxKind.TypeLiteral:
+                case SyntaxKind.MappedType:
                 case SyntaxKind.JSDocTypeLiteral:
                 case SyntaxKind.JSDocRecordType:
-                    return bindAnonymousDeclaration(<TypeLiteralNode>node, SymbolFlags.TypeLiteral, "__type");
+                    return bindAnonymousDeclaration(<Declaration>node, SymbolFlags.TypeLiteral, "__type");
                 case SyntaxKind.ObjectLiteralExpression:
                     return bindObjectLiteralExpression(<ObjectLiteralExpression>node);
                 case SyntaxKind.FunctionExpression:
@@ -2185,15 +2231,6 @@ namespace ts {
         }
 
         function bindClassLikeDeclaration(node: ClassLikeDeclaration) {
-            if (!isDeclarationFile(file) && !isInAmbientContext(node)) {
-                if (getClassExtendsHeritageClauseElement(node) !== undefined) {
-                    emitFlags |= NodeFlags.HasClassExtends;
-                }
-                if (nodeIsDecorated(node)) {
-                    emitFlags |= NodeFlags.HasDecorators;
-                }
-            }
-
             if (node.kind === SyntaxKind.ClassDeclaration) {
                 bindBlockScopedDeclaration(node, SymbolFlags.Class, SymbolFlags.ClassExcludes);
             }
@@ -2263,12 +2300,6 @@ namespace ts {
         }
 
         function bindParameter(node: ParameterDeclaration) {
-            if (!isDeclarationFile(file) &&
-                !isInAmbientContext(node) &&
-                nodeIsDecorated(node)) {
-                emitFlags |= (NodeFlags.HasDecorators | NodeFlags.HasParamDecorators);
-            }
-
             if (inStrictMode) {
                 // It is a SyntaxError if the identifier eval or arguments appears within a FormalParameterList of a
                 // strict mode FunctionLikeDeclaration or FunctionExpression(13.1)
@@ -2326,9 +2357,6 @@ namespace ts {
                 if (isAsyncFunctionLike(node)) {
                     emitFlags |= NodeFlags.HasAsyncFunctions;
                 }
-                if (nodeIsDecorated(node)) {
-                    emitFlags |= NodeFlags.HasDecorators;
-                }
             }
 
             if (currentFlow && isObjectLiteralOrClassExpressionMethod(node)) {
@@ -2495,9 +2523,9 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
-        if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression
+        if (subtreeFlags & TransformFlags.ContainsSpread
             || isSuperOrSuperProperty(expression, expressionKind)) {
-            // If the this node contains a SpreadElementExpression, or is a super call, then it is an ES6
+            // If the this node contains a SpreadExpression, or is a super call, then it is an ES6
             // node.
             transformFlags |= TransformFlags.AssertES2015;
         }
@@ -2526,7 +2554,7 @@ namespace ts {
         if (node.typeArguments) {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
-        if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression) {
+        if (subtreeFlags & TransformFlags.ContainsSpread) {
             // If the this node contains a SpreadElementExpression then it is an ES6
             // node.
             transformFlags |= TransformFlags.AssertES2015;
@@ -2535,16 +2563,18 @@ namespace ts {
         return transformFlags & ~TransformFlags.ArrayLiteralOrCallOrNewExcludes;
     }
 
-
     function computeBinaryExpression(node: BinaryExpression, subtreeFlags: TransformFlags) {
         let transformFlags = subtreeFlags;
         const operatorTokenKind = node.operatorToken.kind;
         const leftKind = node.left.kind;
 
-        if (operatorTokenKind === SyntaxKind.EqualsToken
-            && (leftKind === SyntaxKind.ObjectLiteralExpression
-                || leftKind === SyntaxKind.ArrayLiteralExpression)) {
-            // Destructuring assignments are ES6 syntax.
+        if (operatorTokenKind === SyntaxKind.EqualsToken && leftKind === SyntaxKind.ObjectLiteralExpression) {
+            // Destructuring object assignments with are ES2015 syntax
+            // and possibly ESNext if they contain rest
+            transformFlags |= TransformFlags.AssertESNext | TransformFlags.AssertES2015 | TransformFlags.AssertDestructuringAssignment;
+        }
+        else if (operatorTokenKind === SyntaxKind.EqualsToken && leftKind === SyntaxKind.ArrayLiteralExpression) {
+            // Destructuring assignments are ES2015 syntax.
             transformFlags |= TransformFlags.AssertES2015 | TransformFlags.AssertDestructuringAssignment;
         }
         else if (operatorTokenKind === SyntaxKind.AsteriskAsteriskToken
@@ -2578,6 +2608,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript | TransformFlags.ContainsParameterPropertyAssignments;
         }
 
+        // parameters with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         // If a parameter has an initializer, a binding pattern or a dotDotDot token, then
         // it is ES6 syntax and its container must emit default value assignments or parameter destructuring downlevel.
         if (subtreeFlags & TransformFlags.ContainsBindingPattern || initializer || dotDotDotToken) {
@@ -2696,7 +2731,7 @@ namespace ts {
         }
 
         node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
-        return transformFlags & ~TransformFlags.NodeExcludes;
+        return transformFlags & ~TransformFlags.CatchClauseExcludes;
     }
 
     function computeExpressionWithTypeArguments(node: ExpressionWithTypeArguments, subtreeFlags: TransformFlags) {
@@ -2723,6 +2758,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
+        // function declarations with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
         return transformFlags & ~TransformFlags.ConstructorExcludes;
     }
@@ -2741,6 +2781,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
+        // function declarations with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         // An async method declaration is ES2017 syntax.
         if (hasModifier(node, ModifierFlags.Async)) {
             transformFlags |= TransformFlags.AssertES2017;
@@ -2767,6 +2812,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
+        // function declarations with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
         return transformFlags & ~TransformFlags.MethodOrAccessorExcludes;
     }
@@ -2811,6 +2861,11 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertES2017;
             }
 
+            // function declarations with object rest destructuring are ES Next syntax
+            if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+                transformFlags |= TransformFlags.AssertESNext;
+            }
+
             // If a FunctionDeclaration's subtree has marked the container as needing to capture the
             // lexical this, or the function contains parameters with initializers, then this node is
             // ES6 syntax.
@@ -2848,6 +2903,12 @@ namespace ts {
             transformFlags |= TransformFlags.AssertES2017;
         }
 
+        // function expressions with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
+
         // If a FunctionExpression's subtree has marked the container as needing to capture the
         // lexical this, or the function contains parameters with initializers, then this node is
         // ES6 syntax.
@@ -2885,6 +2946,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertES2017;
         }
 
+        // arrow functions with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         // If an ArrowFunction contains a lexical this, its container must capture the lexical this.
         if (subtreeFlags & TransformFlags.ContainsLexicalThis) {
             transformFlags |= TransformFlags.ContainsCapturedLexicalThis;
@@ -2911,11 +2977,11 @@ namespace ts {
 
     function computeVariableDeclaration(node: VariableDeclaration, subtreeFlags: TransformFlags) {
         let transformFlags = subtreeFlags;
-        const nameKind = node.name.kind;
+        transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
 
-        // A VariableDeclaration with a binding pattern is ES6 syntax.
-        if (nameKind === SyntaxKind.ObjectBindingPattern || nameKind === SyntaxKind.ArrayBindingPattern) {
-            transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+        // A VariableDeclaration containing ObjectRest is ESNext syntax
+        if (subtreeFlags & TransformFlags.ContainsObjectRest) {
+            transformFlags |= TransformFlags.AssertESNext;
         }
 
         // Type annotations are TypeScript syntax.
@@ -3055,6 +3121,10 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertJsx;
                 break;
 
+            case SyntaxKind.ForOfStatement:
+                // for-of might be ESNext if it has a rest destructuring
+                transformFlags |= TransformFlags.AssertESNext;
+                // FALLTHROUGH
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.TemplateHead:
             case SyntaxKind.TemplateMiddle:
@@ -3062,8 +3132,8 @@ namespace ts {
             case SyntaxKind.TemplateExpression:
             case SyntaxKind.TaggedTemplateExpression:
             case SyntaxKind.ShorthandPropertyAssignment:
-            case SyntaxKind.ForOfStatement:
             case SyntaxKind.StaticKeyword:
+            case SyntaxKind.MetaProperty:
                 // These nodes are ES6 syntax.
                 transformFlags |= TransformFlags.AssertES2015;
                 break;
@@ -3102,6 +3172,7 @@ namespace ts {
             case SyntaxKind.ThisType:
             case SyntaxKind.TypeOperator:
             case SyntaxKind.IndexedAccessType:
+            case SyntaxKind.MappedType:
             case SyntaxKind.LiteralType:
                 // Types and signatures are TypeScript syntax, and exclude all other facts.
                 transformFlags = TransformFlags.AssertTypeScript;
@@ -3126,9 +3197,12 @@ namespace ts {
                 }
                 break;
 
-            case SyntaxKind.SpreadElementExpression:
-                // This node is ES6 syntax, but is handled by a containing node.
-                transformFlags |= TransformFlags.ContainsSpreadElementExpression;
+            case SyntaxKind.SpreadElement:
+                transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsSpread;
+                break;
+
+            case SyntaxKind.SpreadAssignment:
+                transformFlags |= TransformFlags.AssertESNext | TransformFlags.ContainsObjectSpread;
                 break;
 
             case SyntaxKind.SuperKeyword:
@@ -3142,9 +3216,23 @@ namespace ts {
                 break;
 
             case SyntaxKind.ObjectBindingPattern:
-            case SyntaxKind.ArrayBindingPattern:
-                // These nodes are ES6 syntax.
                 transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+                if (subtreeFlags & TransformFlags.ContainsRest) {
+                    transformFlags |= TransformFlags.AssertESNext | TransformFlags.ContainsObjectRest;
+                }
+                excludeFlags = TransformFlags.BindingPatternExcludes;
+                break;
+
+            case SyntaxKind.ArrayBindingPattern:
+                transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+                excludeFlags = TransformFlags.BindingPatternExcludes;
+                break;
+
+            case SyntaxKind.BindingElement:
+                transformFlags |= TransformFlags.AssertES2015;
+                if ((<BindingElement>node).dotDotDotToken) {
+                    transformFlags |= TransformFlags.ContainsRest;
+                }
                 break;
 
             case SyntaxKind.Decorator:
@@ -3166,13 +3254,19 @@ namespace ts {
                     transformFlags |= TransformFlags.ContainsLexicalThis;
                 }
 
+                if (subtreeFlags & TransformFlags.ContainsObjectSpread) {
+                    // If an ObjectLiteralExpression contains a spread element, then it
+                    // is an ES next node.
+                    transformFlags |= TransformFlags.AssertESNext;
+                }
+
                 break;
 
             case SyntaxKind.ArrayLiteralExpression:
             case SyntaxKind.NewExpression:
                 excludeFlags = TransformFlags.ArrayLiteralOrCallOrNewExcludes;
-                if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression) {
-                    // If the this node contains a SpreadElementExpression, then it is an ES6
+                if (subtreeFlags & TransformFlags.ContainsSpread) {
+                    // If the this node contains a SpreadExpression, then it is an ES6
                     // node.
                     transformFlags |= TransformFlags.AssertES2015;
                 }
@@ -3264,6 +3358,11 @@ namespace ts {
                 return TransformFlags.TypeExcludes;
             case SyntaxKind.ObjectLiteralExpression:
                 return TransformFlags.ObjectLiteralExcludes;
+            case SyntaxKind.CatchClause:
+                return TransformFlags.CatchClauseExcludes;
+            case SyntaxKind.ObjectBindingPattern:
+            case SyntaxKind.ArrayBindingPattern:
+                return TransformFlags.BindingPatternExcludes;
             default:
                 return TransformFlags.NodeExcludes;
         }

src/compiler/commandLineParser.ts

@@ -77,6 +77,11 @@ namespace ts {
             type: "string",
             description: Diagnostics.Specify_the_object_invoked_for_createElement_and_spread_when_targeting_react_JSX_emit
         },
+        {
+            name: "jsxFactory",
+            type: "string",
+            description: Diagnostics.Specify_the_JSX_factory_function_to_use_when_targeting_react_JSX_emit_e_g_React_createElement_or_h
+        },
         {
             name: "listFiles",
             type: "boolean",
@@ -265,8 +270,9 @@ namespace ts {
                 "es2015": ScriptTarget.ES2015,
                 "es2016": ScriptTarget.ES2016,
                 "es2017": ScriptTarget.ES2017,
+                "esnext": ScriptTarget.ESNext,
             }),
-            description: Diagnostics.Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015,
+            description: Diagnostics.Specify_ECMAScript_target_version_Colon_ES3_default_ES5_ES2015_ES2016_ES2017_or_ESNEXT,
             paramType: Diagnostics.VERSION,
         },
         {
@@ -428,7 +434,8 @@ namespace ts {
                     "es2015.symbol.wellknown": "lib.es2015.symbol.wellknown.d.ts",
                     "es2016.array.include": "lib.es2016.array.include.d.ts",
                     "es2017.object": "lib.es2017.object.d.ts",
-                    "es2017.sharedmemory": "lib.es2017.sharedmemory.d.ts"
+                    "es2017.sharedmemory": "lib.es2017.sharedmemory.d.ts",
+                    "es2017.string": "lib.es2017.string.d.ts",
                 }),
             },
             description: Diagnostics.Specify_library_files_to_be_included_in_the_compilation_Colon
@@ -455,11 +462,18 @@ namespace ts {
     ];
 
     /* @internal */
-    export let typingOptionDeclarations: CommandLineOption[] = [
+    export let typeAcquisitionDeclarations: CommandLineOption[] = [
         {
+            /* @deprecated typingOptions.enableAutoDiscovery
+             * Use typeAcquisition.enable instead.
+             */
             name: "enableAutoDiscovery",
             type: "boolean",
         },
+        {
+            name: "enable",
+            type: "boolean",
+        },
         {
             name: "include",
             type: "list",
@@ -494,6 +508,20 @@ namespace ts {
 
     let optionNameMapCache: OptionNameMap;
 
+    /* @internal */
+    export function convertEnableAutoDiscoveryToEnable(typeAcquisition: TypeAcquisition): TypeAcquisition {
+        // Convert deprecated typingOptions.enableAutoDiscovery to typeAcquisition.enable
+        if (typeAcquisition && typeAcquisition.enableAutoDiscovery !== undefined && typeAcquisition.enable === undefined) {
+            const result: TypeAcquisition = {
+                enable: typeAcquisition.enableAutoDiscovery,
+                include: typeAcquisition.include || [],
+                exclude: typeAcquisition.exclude || []
+            };
+           return result;
+        }
+        return typeAcquisition;
+    }
+
     /* @internal */
     export function getOptionNameMap(): OptionNameMap {
         if (optionNameMapCache) {
@@ -521,14 +549,7 @@ namespace ts {
 
     /* @internal */
     export function parseCustomTypeOption(opt: CommandLineOptionOfCustomType, value: string, errors: Diagnostic[]) {
-        const key = trimString((value || "")).toLowerCase();
-        const map = opt.type;
-        if (key in map) {
-            return map[key];
-        }
-        else {
-            errors.push(createCompilerDiagnosticForInvalidCustomType(opt));
-        }
+        return convertJsonOptionOfCustomType(opt, trimString(value || ""), errors);
     }
 
     /* @internal */
@@ -551,7 +572,6 @@ namespace ts {
         }
     }
 
-    /* @internal */
     export function parseCommandLine(commandLine: string[], readFile?: (path: string) => string): ParsedCommandLine {
         const options: CompilerOptions = {};
         const fileNames: string[] = [];
@@ -600,7 +620,7 @@ namespace ts {
                                     break;
                                 case "boolean":
                                     // boolean flag has optional value true, false, others
-                                    let optValue = args[i];
+                                    const optValue = args[i];
                                     options[opt.name] = optValue !== "false";
                                     // consume next argument as boolean flag value
                                     if (optValue === "false" || optValue === "true") {
@@ -758,7 +778,7 @@ namespace ts {
                             break;
                         default:
                             const value = options[name];
-                            let optionDefinition = optionsNameMap[name.toLowerCase()];
+                            const optionDefinition = optionsNameMap[name.toLowerCase()];
                             if (optionDefinition) {
                                 const customTypeMap = getCustomTypeMapOfCommandLineOption(optionDefinition);
                                 if (!customTypeMap) {
@@ -820,15 +840,16 @@ namespace ts {
       * @param basePath A root directory to resolve relative path entries in the config
       *    file to. e.g. outDir
       */
-    export function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions: CompilerOptions = {}, configFileName?: string, resolutionStack: Path[] = []): ParsedCommandLine {
+    export function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions: CompilerOptions = {}, configFileName?: string, resolutionStack: Path[] = [], extraFileExtensions: FileExtensionInfo[] = []): ParsedCommandLine {
         const errors: Diagnostic[] = [];
+        basePath = normalizeSlashes(basePath);
         const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames);
         const resolvedPath = toPath(configFileName || "", basePath, getCanonicalFileName);
         if (resolutionStack.indexOf(resolvedPath) >= 0) {
             return {
                 options: {},
                 fileNames: [],
-                typingOptions: {},
+                typeAcquisition: {},
                 raw: json,
                 errors: [createCompilerDiagnostic(Diagnostics.Circularity_detected_while_resolving_configuration_Colon_0, [...resolutionStack, resolvedPath].join(" -> "))],
                 wildcardDirectories: {}
@@ -836,7 +857,10 @@ namespace ts {
         }
 
         let options: CompilerOptions = convertCompilerOptionsFromJsonWorker(json["compilerOptions"], basePath, errors, configFileName);
-        const typingOptions: TypingOptions = convertTypingOptionsFromJsonWorker(json["typingOptions"], basePath, errors, configFileName);
+        // typingOptions has been deprecated and is only supported for backward compatibility purposes.
+        // It should be removed in future releases - use typeAcquisition instead.
+        const jsonOptions = json["typeAcquisition"] || json["typingOptions"];
+        const typeAcquisition: TypeAcquisition = convertTypeAcquisitionFromJsonWorker(jsonOptions, basePath, errors, configFileName);
 
         if (json["extends"]) {
             let [include, exclude, files, baseOptions]: [string[], string[], string[], CompilerOptions] = [undefined, undefined, undefined, {}];
@@ -867,7 +891,7 @@ namespace ts {
         return {
             options,
             fileNames,
-            typingOptions,
+            typeAcquisition,
             raw: json,
             errors,
             wildcardDirectories,
@@ -877,7 +901,7 @@ namespace ts {
         function tryExtendsName(extendedConfig: string): [string[], string[], string[], CompilerOptions] {
             // If the path isn't a rooted or relative path, don't try to resolve it (we reserve the right to special case module-id like paths in the future)
             if (!(isRootedDiskPath(extendedConfig) || startsWith(normalizeSlashes(extendedConfig), "./") || startsWith(normalizeSlashes(extendedConfig), "../"))) {
-                errors.push(createCompilerDiagnostic(Diagnostics.The_path_in_an_extends_options_must_be_relative_or_rooted));
+                errors.push(createCompilerDiagnostic(Diagnostics.A_path_in_an_extends_option_must_be_relative_or_rooted_but_0_is_not, extendedConfig));
                 return;
             }
             let extendedConfigPath = toPath(extendedConfig, basePath, getCanonicalFileName);
@@ -944,8 +968,8 @@ namespace ts {
                 errors.push(createCompilerDiagnostic(Diagnostics.Unknown_option_excludes_Did_you_mean_exclude));
             }
             else {
-                // By default, exclude common package folders and the outDir
-                excludeSpecs = ["node_modules", "bower_components", "jspm_packages"];
+                // If no includes were specified, exclude common package folders and the outDir
+                excludeSpecs = includeSpecs ? [] : ["node_modules", "bower_components", "jspm_packages"];
 
                 const outDir = json["compilerOptions"] && json["compilerOptions"]["outDir"];
                 if (outDir) {
@@ -957,7 +981,7 @@ namespace ts {
                 includeSpecs = ["**/*"];
             }
 
-            const result = matchFileNames(fileNames, includeSpecs, excludeSpecs, basePath, options, host, errors);
+            const result = matchFileNames(fileNames, includeSpecs, excludeSpecs, basePath, options, host, errors, extraFileExtensions);
 
             if (result.fileNames.length === 0 && !hasProperty(json, "files") && resolutionStack.length === 0) {
                 errors.push(
@@ -989,9 +1013,9 @@ namespace ts {
         return { options, errors };
     }
 
-    export function convertTypingOptionsFromJson(jsonOptions: any, basePath: string, configFileName?: string): { options: TypingOptions, errors: Diagnostic[] } {
+    export function convertTypeAcquisitionFromJson(jsonOptions: any, basePath: string, configFileName?: string): { options: TypeAcquisition, errors: Diagnostic[] } {
         const errors: Diagnostic[] = [];
-        const options = convertTypingOptionsFromJsonWorker(jsonOptions, basePath, errors, configFileName);
+        const options = convertTypeAcquisitionFromJsonWorker(jsonOptions, basePath, errors, configFileName);
         return { options, errors };
     }
 
@@ -1005,16 +1029,18 @@ namespace ts {
         return options;
     }
 
-    function convertTypingOptionsFromJsonWorker(jsonOptions: any,
-        basePath: string, errors: Diagnostic[], configFileName?: string): TypingOptions {
+    function convertTypeAcquisitionFromJsonWorker(jsonOptions: any,
+        basePath: string, errors: Diagnostic[], configFileName?: string): TypeAcquisition {
+
+        const options: TypeAcquisition = { enable: getBaseFileName(configFileName) === "jsconfig.json", include: [], exclude: [] };
+        const typeAcquisition = convertEnableAutoDiscoveryToEnable(jsonOptions);
+        convertOptionsFromJson(typeAcquisitionDeclarations, typeAcquisition, basePath, options, Diagnostics.Unknown_type_acquisition_option_0, errors);
 
-        const options: TypingOptions = { enableAutoDiscovery: getBaseFileName(configFileName) === "jsconfig.json", include: [], exclude: [] };
-        convertOptionsFromJson(typingOptionDeclarations, jsonOptions, basePath, options, Diagnostics.Unknown_typing_option_0, errors);
         return options;
     }
 
     function convertOptionsFromJson(optionDeclarations: CommandLineOption[], jsonOptions: any, basePath: string,
-        defaultOptions: CompilerOptions | TypingOptions, diagnosticMessage: DiagnosticMessage, errors: Diagnostic[]) {
+        defaultOptions: CompilerOptions | TypeAcquisition, diagnosticMessage: DiagnosticMessage, errors: Diagnostic[]) {
 
         if (!jsonOptions) {
             return;
@@ -1159,7 +1185,7 @@ namespace ts {
      * @param host The host used to resolve files and directories.
      * @param errors An array for diagnostic reporting.
      */
-    function matchFileNames(fileNames: string[], include: string[], exclude: string[], basePath: string, options: CompilerOptions, host: ParseConfigHost, errors: Diagnostic[]): ExpandResult {
+    function matchFileNames(fileNames: string[], include: string[], exclude: string[], basePath: string, options: CompilerOptions, host: ParseConfigHost, errors: Diagnostic[], extraFileExtensions: FileExtensionInfo[]): ExpandResult {
         basePath = normalizePath(basePath);
 
         // The exclude spec list is converted into a regular expression, which allows us to quickly
@@ -1193,7 +1219,7 @@ namespace ts {
 
         // Rather than requery this for each file and filespec, we query the supported extensions
         // once and store it on the expansion context.
-        const supportedExtensions = getSupportedExtensions(options);
+        const supportedExtensions = getSupportedExtensions(options, extraFileExtensions);
 
         // Literal files are always included verbatim. An "include" or "exclude" specification cannot
         // remove a literal file.

src/compiler/comments.ts

@@ -156,6 +156,9 @@ namespace ts {
 
             if (!skipTrailingComments) {
                 emitLeadingComments(detachedRange.end, /*isEmittedNode*/ true);
+                if (hasWrittenComment && !writer.isAtStartOfLine()) {
+                    writer.writeLine();
+                }
             }
 
             if (extendedDiagnostics) {

src/compiler/core.ts

@@ -1,6 +1,11 @@
 /// <reference path="types.ts"/>
 /// <reference path="performance.ts" />
 
+namespace ts {
+    /** The version of the TypeScript compiler release */
+    export const version = "2.2.0";
+}
+
 /* @internal */
 namespace ts {
     /**
@@ -114,7 +119,7 @@ namespace ts {
      */
     export function forEach<T, U>(array: T[] | undefined, callback: (element: T, index: number) => U | undefined): U | undefined {
         if (array) {
-            for (let i = 0, len = array.length; i < len; i++) {
+            for (let i = 0; i < array.length; i++) {
                 const result = callback(array[i], i);
                 if (result) {
                     return result;
@@ -138,7 +143,7 @@ namespace ts {
      */
     export function every<T>(array: T[], callback: (element: T, index: number) => boolean): boolean {
         if (array) {
-            for (let i = 0, len = array.length; i < len; i++) {
+            for (let i = 0; i < array.length; i++) {
                 if (!callback(array[i], i)) {
                     return false;
                 }
@@ -150,7 +155,7 @@ namespace ts {
 
     /** Works like Array.prototype.find, returning `undefined` if no element satisfying the predicate is found. */
     export function find<T>(array: T[], predicate: (element: T, index: number) => boolean): T | undefined {
-        for (let i = 0, len = array.length; i < len; i++) {
+        for (let i = 0; i < array.length; i++) {
             const value = array[i];
             if (predicate(value, i)) {
                 return value;
@@ -164,7 +169,7 @@ namespace ts {
      * This is like `forEach`, but never returns undefined.
      */
     export function findMap<T, U>(array: T[], callback: (element: T, index: number) => U | undefined): U {
-        for (let i = 0, len = array.length; i < len; i++) {
+        for (let i = 0; i < array.length; i++) {
             const result = callback(array[i], i);
             if (result) {
                 return result;
@@ -186,7 +191,7 @@ namespace ts {
 
     export function indexOf<T>(array: T[], value: T): number {
         if (array) {
-            for (let i = 0, len = array.length; i < len; i++) {
+            for (let i = 0; i < array.length; i++) {
                 if (array[i] === value) {
                     return i;
                 }
@@ -196,7 +201,7 @@ namespace ts {
     }
 
     export function indexOfAnyCharCode(text: string, charCodes: number[], start?: number): number {
-        for (let i = start || 0, len = text.length; i < len; i++) {
+        for (let i = start || 0; i < text.length; i++) {
             if (contains(charCodes, text.charCodeAt(i))) {
                 return i;
             }
@@ -566,7 +571,7 @@ namespace ts {
      */
     export function append<T>(to: T[] | undefined, value: T | undefined): T[] | undefined {
         if (value === undefined) return to;
-        if (to === undefined) to = [];
+        if (to === undefined) return [value];
         to.push(value);
         return to;
     }
@@ -587,6 +592,16 @@ namespace ts {
         return to;
     }
 
+    /**
+     * Stable sort of an array. Elements equal to each other maintain their relative position in the array.
+     */
+    export function stableSort<T>(array: T[], comparer: (x: T, y: T) => Comparison = compareValues) {
+        return array
+            .map((_, i) => i) // create array of indices
+            .sort((x, y) => comparer(array[x], array[y]) || compareValues(x, y)) // sort indices by value then position
+            .map(i => array[i]); // get sorted array
+    }
+
     export function rangeEquals<T>(array1: T[], array2: T[], pos: number, end: number) {
         while (pos < end) {
             if (array1[pos] !== array2[pos]) {
@@ -811,6 +826,13 @@ namespace ts {
         }
     }
 
+    export function appendProperty<T>(map: Map<T>, key: string | number, value: T): Map<T> {
+        if (key === undefined || value === undefined) return map;
+        if (map === undefined) map = createMap<T>();
+        map[key] = value;
+        return map;
+    }
+
     export function assign<T1 extends MapLike<{}>, T2, T3>(t: T1, arg1: T2, arg2: T3): T1 & T2 & T3;
     export function assign<T1 extends MapLike<{}>, T2>(t: T1, arg1: T2): T1 & T2;
     export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]): any;
@@ -841,24 +863,6 @@ namespace ts {
         return result;
     }
 
-    /**
-     * Reduce the properties defined on a map-like (but not from its prototype chain).
-     *
-     * NOTE: This is intended for use with MapLike<T> objects. For Map<T> objects, use
-     *       reduceProperties instead as it offers better performance.
-     *
-     * @param map The map-like to reduce
-     * @param callback An aggregation function that is called for each entry in the map
-     * @param initial The initial value for the reduction.
-     */
-    export function reduceOwnProperties<T, U>(map: MapLike<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
-        let result = initial;
-        for (const key in map) if (hasOwnProperty.call(map, key)) {
-            result = callback(result, map[key], String(key));
-        }
-        return result;
-    }
-
     /**
      * Performs a shallow equality comparison of the contents of two map-likes.
      *
@@ -1369,6 +1373,14 @@ namespace ts {
             getEmitScriptTarget(compilerOptions) >= ScriptTarget.ES2015 ? ModuleKind.ES2015 : ModuleKind.CommonJS;
     }
 
+    export function getEmitModuleResolutionKind(compilerOptions: CompilerOptions) {
+        let moduleResolution = compilerOptions.moduleResolution;
+        if (moduleResolution === undefined) {
+            moduleResolution = getEmitModuleKind(compilerOptions) === ModuleKind.CommonJS ? ModuleResolutionKind.NodeJs : ModuleResolutionKind.Classic;
+        }
+        return moduleResolution;
+    }
+
     /* @internal */
     export function hasZeroOrOneAsteriskCharacter(str: string): boolean {
         let seenAsterisk = false;
@@ -1912,8 +1924,18 @@ namespace ts {
     export const supportedJavascriptExtensions = [".js", ".jsx"];
     const allSupportedExtensions = supportedTypeScriptExtensions.concat(supportedJavascriptExtensions);
 
-    export function getSupportedExtensions(options?: CompilerOptions): string[] {
-        return options && options.allowJs ? allSupportedExtensions : supportedTypeScriptExtensions;
+    export function getSupportedExtensions(options?: CompilerOptions, extraFileExtensions?: FileExtensionInfo[]): string[] {
+        const needAllExtensions = options && options.allowJs;
+        if (!extraFileExtensions || extraFileExtensions.length === 0) {
+            return needAllExtensions ? allSupportedExtensions : supportedTypeScriptExtensions;
+        }
+        const extensions = (needAllExtensions ? allSupportedExtensions : supportedTypeScriptExtensions).slice(0);
+        for (const extInfo of extraFileExtensions) {
+            if (needAllExtensions || extInfo.scriptKind === ScriptKind.TS) {
+                extensions.push(extInfo.extension);
+            }
+        }
+        return extensions;
     }
 
     export function hasJavaScriptFileExtension(fileName: string) {
@@ -1924,10 +1946,10 @@ namespace ts {
         return forEach(supportedTypeScriptExtensions, extension => fileExtensionIs(fileName, extension));
     }
 
-    export function isSupportedSourceFileName(fileName: string, compilerOptions?: CompilerOptions) {
+    export function isSupportedSourceFileName(fileName: string, compilerOptions?: CompilerOptions, extraFileExtensions?: FileExtensionInfo[]) {
         if (!fileName) { return false; }
 
-        for (const extension of getSupportedExtensions(compilerOptions)) {
+        for (const extension of getSupportedExtensions(compilerOptions, extraFileExtensions)) {
             if (fileExtensionIs(fileName, extension)) {
                 return true;
             }
@@ -2087,6 +2109,17 @@ namespace ts {
     }
 
     /** Remove an item from an array, moving everything to its right one space left. */
+    export function orderedRemoveItem<T>(array: T[], item: T): boolean {
+        for (let i = 0; i < array.length; i++) {
+            if (array[i] === item) {
+                orderedRemoveItemAt(array, i);
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /** Remove an item by index from an array, moving everything to its right one space left. */
     export function orderedRemoveItemAt<T>(array: T[], index: number): void {
         // This seems to be faster than either `array.splice(i, 1)` or `array.copyWithin(i, i+ 1)`.
         for (let i = index; i < array.length - 1; i++) {
@@ -2210,6 +2243,13 @@ namespace ts {
      * Path must have a valid extension.
      */
     export function extensionFromPath(path: string): Extension {
+        const ext = tryGetExtensionFromPath(path);
+        if (ext !== undefined) {
+            return ext;
+        }
+        Debug.fail(`File ${path} has unknown extension.`);
+    }
+    export function tryGetExtensionFromPath(path: string): Extension | undefined {
         if (fileExtensionIs(path, ".d.ts")) {
             return Extension.Dts;
         }
@@ -2225,7 +2265,5 @@ namespace ts {
         if (fileExtensionIs(path, ".jsx")) {
             return Extension.Jsx;
         }
-        Debug.fail(`File ${path} has unknown extension.`);
-        return Extension.Js;
     }
 }

src/compiler/declarationEmitter.ts

@@ -194,6 +194,7 @@ namespace ts {
             writer.writeSpace = writer.write;
             writer.writeStringLiteral = writer.writeLiteral;
             writer.writeParameter = writer.write;
+            writer.writeProperty = writer.write;
             writer.writeSymbol = writer.write;
             setWriter(writer);
         }
@@ -371,7 +372,7 @@ namespace ts {
 
         function writeJsDocComments(declaration: Node) {
             if (declaration) {
-                const jsDocComments = getJsDocCommentsFromText(declaration, currentText);
+                const jsDocComments = getJSDocCommentRanges(declaration, currentText);
                 emitNewLineBeforeLeadingComments(currentLineMap, writer, declaration, jsDocComments);
                 // jsDoc comments are emitted at /*leading comment1 */space/*leading comment*/space
                 emitComments(currentText, currentLineMap, writer, jsDocComments, /*leadingSeparator*/ false, /*trailingSeparator*/ true, newLine, writeCommentRange);
@@ -416,7 +417,9 @@ namespace ts {
                 case SyntaxKind.TypeOperator:
                     return emitTypeOperator(<TypeOperatorNode>type);
                 case SyntaxKind.IndexedAccessType:
-                    return emitPropertyAccessType(<IndexedAccessTypeNode>type);
+                    return emitIndexedAccessType(<IndexedAccessTypeNode>type);
+                case SyntaxKind.MappedType:
+                    return emitMappedType(<MappedTypeNode>type);
                 case SyntaxKind.FunctionType:
                 case SyntaxKind.ConstructorType:
                     return emitSignatureDeclarationWithJsDocComments(<FunctionOrConstructorTypeNode>type);
@@ -516,13 +519,39 @@ namespace ts {
                 emitType(type.type);
             }
 
-            function emitPropertyAccessType(node: IndexedAccessTypeNode) {
+            function emitIndexedAccessType(node: IndexedAccessTypeNode) {
                 emitType(node.objectType);
                 write("[");
                 emitType(node.indexType);
                 write("]");
             }
 
+            function emitMappedType(node: MappedTypeNode) {
+                const prevEnclosingDeclaration = enclosingDeclaration;
+                enclosingDeclaration = node;
+                write("{");
+                writeLine();
+                increaseIndent();
+                if (node.readonlyToken) {
+                    write("readonly ");
+                }
+                write("[");
+                writeEntityName(node.typeParameter.name);
+                write(" in ");
+                emitType(node.typeParameter.constraint);
+                write("]");
+                if (node.questionToken) {
+                    write("?");
+                }
+                write(": ");
+                emitType(node.type);
+                write(";");
+                writeLine();
+                decreaseIndent();
+                write("}");
+                enclosingDeclaration = prevEnclosingDeclaration;
+            }
+
             function emitTypeLiteral(type: TypeLiteralNode) {
                 write("{");
                 if (type.members.length) {
@@ -1009,6 +1038,10 @@ namespace ts {
                             diagnosticMessage = Diagnostics.Type_parameter_0_of_exported_function_has_or_is_using_private_name_1;
                             break;
 
+                        case SyntaxKind.TypeAliasDeclaration:
+                            diagnosticMessage = Diagnostics.Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1;
+                            break;
+
                         default:
                             Debug.fail("This is unknown parent for type parameter: " + node.parent.kind);
                     }
@@ -1115,7 +1148,10 @@ namespace ts {
             const prevEnclosingDeclaration = enclosingDeclaration;
             enclosingDeclaration = node;
             emitTypeParameters(node.typeParameters);
-            emitHeritageClause(getInterfaceBaseTypeNodes(node), /*isImplementsList*/ false);
+            const interfaceExtendsTypes = filter(getInterfaceBaseTypeNodes(node), base => isEntityNameExpression(base.expression));
+            if (interfaceExtendsTypes && interfaceExtendsTypes.length) {
+                emitHeritageClause(interfaceExtendsTypes, /*isImplementsList*/ false);
+            }
             write(" {");
             writeLine();
             increaseIndent();
@@ -1590,6 +1626,12 @@ namespace ts {
                             Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_private_name_1;
 
+                    case SyntaxKind.IndexSignature:
+                        // Interfaces cannot have parameter types that cannot be named
+                        return symbolAccessibilityResult.errorModuleName ?
+                            Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
+                            Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1;
+
                     case SyntaxKind.MethodDeclaration:
                     case SyntaxKind.MethodSignature:
                         if (hasModifier(node.parent, ModifierFlags.Static)) {

src/compiler/diagnosticMessages.json

@@ -227,7 +227,7 @@
         "category": "Error",
         "code": 1084
     },
-    "Octal literals are not available when targeting ECMAScript 5 and higher.": {
+    "Octal literals are not available when targeting ECMAScript 5 and higher. Use the syntax '{0}'.": {
         "category": "Error",
         "code": 1085
     },
@@ -851,6 +851,14 @@
         "category": "Error",
         "code": 1317
     },
+    "An abstract accessor cannot have an implementation.": {
+        "category": "Error",
+        "code": 1318
+    },
+    "A default export can only be used in an ECMAScript-style module.": {
+        "category": "Error",
+        "code": 1319
+    },
     "Duplicate identifier '{0}'.": {
         "category": "Error",
         "code": 2300
@@ -1023,6 +1031,10 @@
         "category": "Error",
         "code": 2342
     },
+    "This syntax requires an imported helper named '{1}', but module '{0}' has no exported member '{1}'.": {
+        "category": "Error",
+        "code": 2343
+    },
     "Type '{0}' does not satisfy the constraint '{1}'.": {
         "category": "Error",
         "code": 2344
@@ -1063,6 +1075,10 @@
         "category": "Error",
         "code": 2353
     },
+    "This syntax requires an imported helper but module '{0}' cannot be found.": {
+        "category": "Error",
+        "code": 2354
+    },
     "A function whose declared type is neither 'void' nor 'any' must return a value.": {
         "category": "Error",
         "code": 2355
@@ -1455,7 +1471,7 @@
         "category": "Error",
         "code": 2461
     },
-    "A rest element must be last in an array destructuring pattern": {
+    "A rest element must be last in a destructuring pattern": {
         "category": "Error",
         "code": 2462
     },
@@ -1731,7 +1747,7 @@
         "category": "Error",
         "code": 2535
     },
-    "Type '{0}' is not constrained to 'keyof {1}'.": {
+    "Type '{0}' cannot be used to index type '{1}'.": {
         "category": "Error",
         "code": 2536
     },
@@ -1759,6 +1775,14 @@
         "category": "Error",
         "code": 2542
     },
+    "Duplicate identifier '_newTarget'. Compiler uses variable declaration '_newTarget' to capture 'new.target' meta-property reference.": {
+        "category": "Error",
+        "code": 2543
+    },
+    "Expression resolves to variable declaration '_newTarget' that compiler uses to capture 'new.target' meta-property reference.": {
+        "category": "Error",
+        "code": 2544
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
@@ -1795,6 +1819,10 @@
         "category": "Error",
         "code": 2608
     },
+    "JSX spread child must be an array type.": {
+        "category": "Error",
+        "code": 2609
+    },
     "Cannot emit namespaced JSX elements in React": {
         "category": "Error",
         "code": 2650
@@ -1987,6 +2015,31 @@
         "category": "Error",
         "code": 2699
     },
+    "Spread types may only be created from object types.": {
+        "category": "Error",
+        "code": 2698
+    },
+    "Rest types may only be created from object types.": {
+        "category": "Error",
+        "code": 2700
+    },
+    "The target of an object rest assignment must be a variable or a property access.": {
+        "category": "Error",
+        "code": 2701
+    },
+    "'{0}' only refers to a type, but is being used as a namespace here.": {
+        "category": "Error",
+        "code": 2702
+    },
+    "The operand of a delete operator must be a property reference": {
+        "category": "Error",
+        "code": 2703
+    },
+    "The operand of a delete operator cannot be a read-only property": {
+        "category": "Error",
+        "code": 2704
+    },
+
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
         "code": 4000
@@ -2267,10 +2320,23 @@
         "category": "Error",
         "code": 4082
     },
+    "Type parameter '{0}' of exported type alias has or is using private name '{1}'.": {
+        "category": "Error",
+        "code": 4083
+    },
     "Conflicting definitions for '{0}' found at '{1}' and '{2}'. Consider installing a specific version of this library to resolve the conflict.": {
         "category": "Message",
         "code": 4090
     },
+    "Parameter '{0}' of index signature from exported interface has or is using name '{1}' from private module '{2}'.": {
+        "category": "Error",
+        "code": 4091
+    },
+    "Parameter '{0}' of index signature from exported interface has or is using private name '{1}'.": {
+        "category": "Error",
+        "code": 4092
+    },
+
     "The current host does not support the '{0}' option.": {
         "category": "Error",
         "code": 5001
@@ -2383,6 +2449,10 @@
         "category": "Error",
         "code": 5066
     },
+    "Invalid value for 'jsxFactory'. '{0}' is not a valid identifier or qualified-name.": {
+        "category": "Error",
+        "code": 5067
+    },
     "Concatenate and emit output to single file.": {
         "category": "Message",
         "code": 6001
@@ -2431,7 +2501,7 @@
         "category": "Message",
         "code": 6012
     },
-    "Specify ECMAScript target version: 'ES3' (default), 'ES5', or 'ES2015'": {
+    "Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'": {
         "category": "Message",
         "code": 6015
     },
@@ -2643,6 +2713,10 @@
         "category": "Message",
         "code": 6080
     },
+    "File '{0}' has an unsupported extension, so skipping it.": {
+        "category": "Message",
+        "code": 6081
+    },
     "Only 'amd' and 'system' modules are supported alongside --{0}.": {
         "category": "Error",
         "code": 6082
@@ -2695,7 +2769,7 @@
         "category": "Message",
         "code": 6094
     },
-    "Loading module as file / folder, candidate module location '{0}'.": {
+    "Loading module as file / folder, candidate module location '{0}', target file type '{1}'.": {
         "category": "Message",
         "code": 6095
     },
@@ -2707,7 +2781,7 @@
         "category": "Message",
         "code": 6097
     },
-    "Loading module '{0}' from 'node_modules' folder.": {
+    "Loading module '{0}' from 'node_modules' folder, target file type '{1}'.": {
         "category": "Message",
         "code": 6098
     },
@@ -2899,6 +2973,18 @@
         "category": "Message",
         "code": 6145
     },
+    "Specify the JSX factory function to use when targeting 'react' JSX emit, e.g. 'React.createElement' or 'h'.": {
+        "category": "Message",
+        "code": 6146
+    },
+    "Resolution for module '{0}' was found in cache.": {
+        "category": "Message",
+        "code": 6147
+    },
+    "Directory '{0}' does not exist, skipping all lookups in it.": {
+        "category": "Message",
+        "code": 6148
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
@@ -3071,6 +3157,10 @@
         "category": "Error",
         "code": 9003
     },
+    "Language service is disabled.": {
+        "category": "Error",
+        "code": 9004
+    },
     "JSX attributes must only be assigned a non-empty 'expression'.": {
         "category": "Error",
         "code": 17000
@@ -3111,16 +3201,28 @@
         "category": "Error",
         "code": 17009
     },
-    "Unknown typing option '{0}'.": {
+    "Unknown type acquisition option '{0}'.": {
         "category": "Error",
         "code": 17010
     },
+    "'super' must be called before accessing a property of 'super' in the constructor of a derived class.": {
+        "category": "Error",
+        "code": 17011
+    },
+    "'{0}' is not a valid meta-property for keyword '{1}'. Did you mean '{0}'?": {
+        "category": "Error",
+        "code": 17012
+    },
+    "Meta-property '{0}' is only allowed in the body of a function declaration, function expression, or constructor.": {
+        "category": "Error",
+        "code": 17013
+    },
 
     "Circularity detected while resolving configuration: {0}": {
         "category": "Error",
         "code": 18000
     },
-    "The path in an 'extends' options must be relative or rooted.": {
+    "A path in an 'extends' option must be relative or rooted, but '{0}' is not.": {
         "category": "Error",
         "code": 18001
     },
@@ -3164,5 +3266,29 @@
     "Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig": {
         "category": "Error",
         "code": 90009
+    },
+    "Type '{0}' is not assignable to type '{1}'. Two different types with this name exist, but they are unrelated.": {
+        "category": "Error",
+        "code": 90010
+    },
+    "Import {0} from {1}": {
+        "category": "Message",
+        "code": 90013
+    },
+    "Change {0} to {1}": {
+        "category": "Message",
+        "code": 90014
+    },
+    "Add {0} to existing import declaration from {1}": {
+        "category": "Message",
+        "code": 90015
+    },
+    "Octal literal types must use ES2015 syntax. Use the syntax '{0}'.": {
+        "category": "Error",
+        "code": 8017
+    },
+    "Octal literals are not allowed in enums members initializer. Use the syntax '{0}'.": {
+        "category": "Error",
+        "code": 8018
     }
 }

src/compiler/emitter.ts

@@ -20,174 +20,6 @@ namespace ts {
     export function emitFiles(resolver: EmitResolver, host: EmitHost, targetSourceFile: SourceFile, emitOnlyDtsFiles?: boolean): EmitResult {
         const delimiters = createDelimiterMap();
         const brackets = createBracketsMap();
-
-        // emit output for the __extends helper function
-        const extendsHelper = `
-var __extends = (this && this.__extends) || function (d, b) {
-    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
-    function __() { this.constructor = d; }
-    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-};`;
-
-        // Emit output for the __assign helper function.
-        // This is typically used for JSX spread attributes,
-        // and can be used for object literal spread properties.
-        const assignHelper = `
-var __assign = (this && this.__assign) || Object.assign || function(t) {
-    for (var s, i = 1, n = arguments.length; i < n; i++) {
-        s = arguments[i];
-        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
-            t[p] = s[p];
-    }
-    return t;
-};`;
-
-        // emit output for the __decorate helper function
-        const decorateHelper = `
-var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
-    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
-    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
-    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
-    return c > 3 && r && Object.defineProperty(target, key, r), r;
-};`;
-
-        // emit output for the __metadata helper function
-        const metadataHelper = `
-var __metadata = (this && this.__metadata) || function (k, v) {
-    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
-};`;
-
-        // emit output for the __param helper function
-        const paramHelper = `
-var __param = (this && this.__param) || function (paramIndex, decorator) {
-    return function (target, key) { decorator(target, key, paramIndex); }
-};`;
-
-        // emit output for the __awaiter helper function
-        const awaiterHelper = `
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments)).next());
-    });
-};`;
-
-        // The __generator helper is used by down-level transformations to emulate the runtime
-        // semantics of an ES2015 generator function. When called, this helper returns an
-        // object that implements the Iterator protocol, in that it has `next`, `return`, and
-        // `throw` methods that step through the generator when invoked.
-        //
-        // parameters:
-        //  thisArg  The value to use as the `this` binding for the transformed generator body.
-        //  body     A function that acts as the transformed generator body.
-        //
-        // variables:
-        //  _       Persistent state for the generator that is shared between the helper and the
-        //          generator body. The state object has the following members:
-        //            sent() - A method that returns or throws the current completion value.
-        //            label  - The next point at which to resume evaluation of the generator body.
-        //            trys   - A stack of protected regions (try/catch/finally blocks).
-        //            ops    - A stack of pending instructions when inside of a finally block.
-        //  f       A value indicating whether the generator is executing.
-        //  y       An iterator to delegate for a yield*.
-        //  t       A temporary variable that holds one of the following values (note that these
-        //          cases do not overlap):
-        //          - The completion value when resuming from a `yield` or `yield*`.
-        //          - The error value for a catch block.
-        //          - The current protected region (array of try/catch/finally/end labels).
-        //          - The verb (`next`, `throw`, or `return` method) to delegate to the expression
-        //            of a `yield*`.
-        //          - The result of evaluating the verb delegated to the expression of a `yield*`.
-        //
-        // functions:
-        //  verb(n)     Creates a bound callback to the `step` function for opcode `n`.
-        //  step(op)    Evaluates opcodes in a generator body until execution is suspended or
-        //              completed.
-        //
-        // The __generator helper understands a limited set of instructions:
-        //  0: next(value?)     - Start or resume the generator with the specified value.
-        //  1: throw(error)     - Resume the generator with an exception. If the generator is
-        //                        suspended inside of one or more protected regions, evaluates
-        //                        any intervening finally blocks between the current label and
-        //                        the nearest catch block or function boundary. If uncaught, the
-        //                        exception is thrown to the caller.
-        //  2: return(value?)   - Resume the generator as if with a return. If the generator is
-        //                        suspended inside of one or more protected regions, evaluates any
-        //                        intervening finally blocks.
-        //  3: break(label)     - Jump to the specified label. If the label is outside of the
-        //                        current protected region, evaluates any intervening finally
-        //                        blocks.
-        //  4: yield(value?)    - Yield execution to the caller with an optional value. When
-        //                        resumed, the generator will continue at the next label.
-        //  5: yield*(value)    - Delegates evaluation to the supplied iterator. When
-        //                        delegation completes, the generator will continue at the next
-        //                        label.
-        //  6: catch(error)     - Handles an exception thrown from within the generator body. If
-        //                        the current label is inside of one or more protected regions,
-        //                        evaluates any intervening finally blocks between the current
-        //                        label and the nearest catch block or function boundary. If
-        //                        uncaught, the exception is thrown to the caller.
-        //  7: endfinally       - Ends a finally block, resuming the last instruction prior to
-        //                        entering a finally block.
-        //
-        // For examples of how these are used, see the comments in ./transformers/generators.ts
-        const generatorHelper = `
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t;
-    return { next: verb(0), "throw": verb(1), "return": verb(2) };
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = y[op[0] & 2 ? "return" : op[0] ? "throw" : "next"]) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [0, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};`;
-
-        // emit output for the __export helper function
-        const exportStarHelper = `
-function __export(m) {
-    for (var p in m) if (!exports.hasOwnProperty(p)) exports[p] = m[p];
-}`;
-
-        // emit output for the UMD helper function.
-        const umdHelper = `
-(function (dependencies, factory) {
-    if (typeof module === 'object' && typeof module.exports === 'object') {
-        var v = factory(require, exports); if (v !== undefined) module.exports = v;
-    }
-    else if (typeof define === 'function' && define.amd) {
-        define(dependencies, factory);
-    }
-})`;
-
-        const superHelper = `
-const _super = name => super[name];`;
-
-        const advancedSuperHelper = `
-const _super = (function (geti, seti) {
-    const cache = Object.create(null);
-    return name => cache[name] || (cache[name] = { get value() { return geti(name); }, set value(v) { seti(name, v); } });
-})(name => super[name], (name, value) => super[name] = value);`;
-
         const compilerOptions = host.getCompilerOptions();
         const languageVersion = getEmitScriptTarget(compilerOptions);
         const moduleKind = getEmitModuleKind(compilerOptions);
@@ -224,11 +56,7 @@ const _super = (function (geti, seti) {
         let currentSourceFile: SourceFile;
         let currentText: string;
         let currentFileIdentifiers: Map<string>;
-        let extendsEmitted: boolean;
-        let assignEmitted: boolean;
-        let decorateEmitted: boolean;
-        let paramEmitted: boolean;
-        let awaiterEmitted: boolean;
+        let bundledHelpers: Map<boolean>;
         let isOwnFileEmit: boolean;
         let emitSkipped = false;
 
@@ -293,12 +121,13 @@ const _super = (function (geti, seti) {
             nodeIdToGeneratedName = [];
             autoGeneratedIdToGeneratedName = [];
             generatedNameSet = createMap<string>();
+            bundledHelpers = isBundledEmit ? createMap<boolean>() : undefined;
             isOwnFileEmit = !isBundledEmit;
 
             // Emit helpers from all the files
             if (isBundledEmit && moduleKind) {
                 for (const sourceFile of sourceFiles) {
-                    emitEmitHelpers(sourceFile);
+                    emitHelpers(sourceFile, /*isBundle*/ true);
                 }
             }
 
@@ -314,7 +143,7 @@ const _super = (function (geti, seti) {
 
             // Write the source map
             if (compilerOptions.sourceMap && !compilerOptions.inlineSourceMap) {
-                writeFile(host, emitterDiagnostics, sourceMapFilePath, sourceMap.getText(),  /*writeByteOrderMark*/ false);
+                writeFile(host, emitterDiagnostics, sourceMapFilePath, sourceMap.getText(),  /*writeByteOrderMark*/ false, sourceFiles);
             }
 
             // Record source map data for the test harness.
@@ -323,7 +152,7 @@ const _super = (function (geti, seti) {
             }
 
             // Write the output file
-            writeFile(host, emitterDiagnostics, jsFilePath, writer.getText(), compilerOptions.emitBOM);
+            writeFile(host, emitterDiagnostics, jsFilePath, writer.getText(), compilerOptions.emitBOM, sourceFiles);
 
             // Reset state
             sourceMap.reset();
@@ -333,11 +162,6 @@ const _super = (function (geti, seti) {
             tempFlags = TempFlags.Auto;
             currentSourceFile = undefined;
             currentText = undefined;
-            extendsEmitted = false;
-            assignEmitted = false;
-            decorateEmitted = false;
-            paramEmitted = false;
-            awaiterEmitted = false;
             isOwnFileEmit = false;
         }
 
@@ -597,7 +421,9 @@ const _super = (function (geti, seti) {
                 case SyntaxKind.TypeOperator:
                     return emitTypeOperator(<TypeOperatorNode>node);
                 case SyntaxKind.IndexedAccessType:
-                    return emitPropertyAccessType(<IndexedAccessTypeNode>node);
+                    return emitIndexedAccessType(<IndexedAccessTypeNode>node);
+                case SyntaxKind.MappedType:
+                    return emitMappedType(<MappedTypeNode>node);
                 case SyntaxKind.LiteralType:
                     return emitLiteralType(<LiteralTypeNode>node);
 
@@ -732,6 +558,8 @@ const _super = (function (geti, seti) {
                     return emitPropertyAssignment(<PropertyAssignment>node);
                 case SyntaxKind.ShorthandPropertyAssignment:
                     return emitShorthandPropertyAssignment(<ShorthandPropertyAssignment>node);
+                case SyntaxKind.SpreadAssignment:
+                    return emitSpreadAssignment(node as SpreadAssignment);
 
                 // Enum
                 case SyntaxKind.EnumMember:
@@ -822,8 +650,8 @@ const _super = (function (geti, seti) {
                     return emitTemplateExpression(<TemplateExpression>node);
                 case SyntaxKind.YieldExpression:
                     return emitYieldExpression(<YieldExpression>node);
-                case SyntaxKind.SpreadElementExpression:
-                    return emitSpreadElementExpression(<SpreadElementExpression>node);
+                case SyntaxKind.SpreadElement:
+                    return emitSpreadExpression(<SpreadElement>node);
                 case SyntaxKind.ClassExpression:
                     return emitClassExpression(<ClassExpression>node);
                 case SyntaxKind.OmittedExpression:
@@ -832,6 +660,8 @@ const _super = (function (geti, seti) {
                     return emitAsExpression(<AsExpression>node);
                 case SyntaxKind.NonNullExpression:
                     return emitNonNullExpression(<NonNullExpression>node);
+                case SyntaxKind.MetaProperty:
+                    return emitMetaProperty(<MetaProperty>node);
 
                 // JSX
                 case SyntaxKind.JsxElement:
@@ -879,12 +709,7 @@ const _super = (function (geti, seti) {
         //
 
         function emitIdentifier(node: Identifier) {
-            if (getEmitFlags(node) & EmitFlags.UMDDefine) {
-                writeLines(umdHelper);
-            }
-            else {
-                write(getTextOfNode(node, /*includeTrivia*/ false));
-            }
+            write(getTextOfNode(node, /*includeTrivia*/ false));
         }
 
         //
@@ -1098,13 +923,36 @@ const _super = (function (geti, seti) {
             emit(node.type);
         }
 
-        function emitPropertyAccessType(node: IndexedAccessTypeNode) {
+        function emitIndexedAccessType(node: IndexedAccessTypeNode) {
             emit(node.objectType);
             write("[");
             emit(node.indexType);
             write("]");
         }
 
+        function emitMappedType(node: MappedTypeNode) {
+            write("{");
+            writeLine();
+            increaseIndent();
+            if (node.readonlyToken) {
+                write("readonly ");
+            }
+            write("[");
+            emit(node.typeParameter.name);
+            write(" in ");
+            emit(node.typeParameter.constraint);
+            write("]");
+            if (node.questionToken) {
+                write("?");
+            }
+            write(": ");
+            emit(node.type);
+            write(";");
+            writeLine();
+            decreaseIndent();
+            write("}");
+        }
+
         function emitLiteralType(node: LiteralTypeNode) {
             emitExpression(node.literal);
         }
@@ -1374,7 +1222,7 @@ const _super = (function (geti, seti) {
             emitExpressionWithPrefix(" ", node.expression);
         }
 
-        function emitSpreadElementExpression(node: SpreadElementExpression) {
+        function emitSpreadExpression(node: SpreadElement) {
             write("...");
             emitExpression(node.expression);
         }
@@ -1401,6 +1249,12 @@ const _super = (function (geti, seti) {
             write("!");
         }
 
+        function emitMetaProperty(node: MetaProperty) {
+            writeToken(node.keywordToken, node.pos);
+            write(".");
+            emit(node.name);
+        }
+
         //
         // Misc
         //
@@ -1457,28 +1311,28 @@ const _super = (function (geti, seti) {
             writeToken(SyntaxKind.OpenParenToken, openParenPos, node);
             emitExpression(node.expression);
             writeToken(SyntaxKind.CloseParenToken, node.expression.end, node);
-            emitEmbeddedStatement(node.thenStatement);
+            emitEmbeddedStatement(node, node.thenStatement);
             if (node.elseStatement) {
-                writeLine();
+                writeLineOrSpace(node);
                 writeToken(SyntaxKind.ElseKeyword, node.thenStatement.end, node);
                 if (node.elseStatement.kind === SyntaxKind.IfStatement) {
                     write(" ");
                     emit(node.elseStatement);
                 }
                 else {
-                    emitEmbeddedStatement(node.elseStatement);
+                    emitEmbeddedStatement(node, node.elseStatement);
                 }
             }
         }
 
         function emitDoStatement(node: DoStatement) {
             write("do");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
             if (isBlock(node.statement)) {
                 write(" ");
             }
             else {
-                writeLine();
+                writeLineOrSpace(node);
             }
 
             write("while (");
@@ -1490,7 +1344,7 @@ const _super = (function (geti, seti) {
             write("while (");
             emitExpression(node.expression);
             write(")");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForStatement(node: ForStatement) {
@@ -1503,7 +1357,7 @@ const _super = (function (geti, seti) {
             write(";");
             emitExpressionWithPrefix(" ", node.incrementor);
             write(")");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForInStatement(node: ForInStatement) {
@@ -1514,7 +1368,7 @@ const _super = (function (geti, seti) {
             write(" in ");
             emitExpression(node.expression);
             writeToken(SyntaxKind.CloseParenToken, node.expression.end);
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForOfStatement(node: ForOfStatement) {
@@ -1525,7 +1379,7 @@ const _super = (function (geti, seti) {
             write(" of ");
             emitExpression(node.expression);
             writeToken(SyntaxKind.CloseParenToken, node.expression.end);
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForBinding(node: VariableDeclarationList | Expression) {
@@ -1561,7 +1415,7 @@ const _super = (function (geti, seti) {
             write("with (");
             emitExpression(node.expression);
             write(")");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitSwitchStatement(node: SwitchStatement) {
@@ -1589,9 +1443,12 @@ const _super = (function (geti, seti) {
         function emitTryStatement(node: TryStatement) {
             write("try ");
             emit(node.tryBlock);
-            emit(node.catchClause);
+            if (node.catchClause) {
+                writeLineOrSpace(node);
+                emit(node.catchClause);
+            }
             if (node.finallyBlock) {
-                writeLine();
+                writeLineOrSpace(node);
                 write("finally ");
                 emit(node.finallyBlock);
             }
@@ -2003,6 +1860,9 @@ const _super = (function (geti, seti) {
         function emitJsxExpression(node: JsxExpression) {
             if (node.expression) {
                 write("{");
+                if (node.dotDotDotToken) {
+                    write("...");
+                }
                 emitExpression(node.expression);
                 write("}");
             }
@@ -2102,6 +1962,13 @@ const _super = (function (geti, seti) {
             }
         }
 
+        function emitSpreadAssignment(node: SpreadAssignment) {
+            if (node.expression) {
+                write("...");
+                emitExpression(node.expression);
+            }
+        }
+
         //
         // Enum
         //
@@ -2158,85 +2025,39 @@ const _super = (function (geti, seti) {
             return statements.length;
         }
 
-        function emitHelpers(node: Node) {
-            const emitFlags = getEmitFlags(node);
-            let helpersEmitted = false;
-            if (emitFlags & EmitFlags.EmitEmitHelpers) {
-                helpersEmitted = emitEmitHelpers(currentSourceFile);
-            }
-
-            if (emitFlags & EmitFlags.EmitExportStar) {
-                writeLines(exportStarHelper);
-                helpersEmitted = true;
-            }
-
-            if (emitFlags & EmitFlags.EmitSuperHelper) {
-                writeLines(superHelper);
-                helpersEmitted = true;
-            }
-
-            if (emitFlags & EmitFlags.EmitAdvancedSuperHelper) {
-                writeLines(advancedSuperHelper);
-                helpersEmitted = true;
-            }
-
-            return helpersEmitted;
-        }
-
-        function emitEmitHelpers(node: SourceFile) {
-            // Only emit helpers if the user did not say otherwise.
-            if (compilerOptions.noEmitHelpers) {
-                return false;
-            }
-
-            // Don't emit helpers if we can import them.
-            if (compilerOptions.importHelpers
-                && (isExternalModule(node) || compilerOptions.isolatedModules)) {
-                return false;
-            }
+        function emitHelpers(node: Node, isBundle?: boolean) {
+            const sourceFile = isSourceFile(node) ? node : currentSourceFile;
+            const shouldSkip = compilerOptions.noEmitHelpers || (sourceFile && getExternalHelpersModuleName(sourceFile) !== undefined);
+            const shouldBundle = isSourceFile(node) && !isOwnFileEmit;
 
             let helpersEmitted = false;
+            const helpers = getEmitHelpers(node);
+            if (helpers) {
+                for (const helper of stableSort(helpers, compareEmitHelpers)) {
+                    if (!helper.scoped) {
+                        // Skip the helper if it can be skipped and the noEmitHelpers compiler
+                        // option is set, or if it can be imported and the importHelpers compiler
+                        // option is set.
+                        if (shouldSkip) continue;
 
-            // Only Emit __extends function when target ES5.
-            // For target ES6 and above, we can emit classDeclaration as is.
-            if ((languageVersion < ScriptTarget.ES2015) && (!extendsEmitted && node.flags & NodeFlags.HasClassExtends)) {
-                writeLines(extendsHelper);
-                extendsEmitted = true;
-                helpersEmitted = true;
-            }
+                        // Skip the helper if it can be bundled but hasn't already been emitted and we
+                        // are emitting a bundled module.
+                        if (shouldBundle) {
+                            if (bundledHelpers[helper.name]) {
+                                continue;
+                            }
 
-            if (compilerOptions.jsx !== JsxEmit.Preserve && !assignEmitted && (node.flags & NodeFlags.HasJsxSpreadAttributes)) {
-                writeLines(assignHelper);
-                assignEmitted = true;
-            }
+                            bundledHelpers[helper.name] = true;
+                        }
+                    }
+                    else if (isBundle) {
+                        // Skip the helper if it is scoped and we are emitting bundled helpers
+                        continue;
+                    }
 
-            if (!decorateEmitted && node.flags & NodeFlags.HasDecorators) {
-                writeLines(decorateHelper);
-                if (compilerOptions.emitDecoratorMetadata) {
-                    writeLines(metadataHelper);
+                    writeLines(helper.text);
+                    helpersEmitted = true;
                 }
-
-                decorateEmitted = true;
-                helpersEmitted = true;
-            }
-
-            if (!paramEmitted && node.flags & NodeFlags.HasParamDecorators) {
-                writeLines(paramHelper);
-                paramEmitted = true;
-                helpersEmitted = true;
-            }
-
-            // Only emit __awaiter function when target ES5/ES6.
-            // Only emit __generator function when target ES5.
-            // For target ES2017 and above, we can emit async/await as is.
-            if ((languageVersion < ScriptTarget.ES2017) && (!awaiterEmitted && node.flags & NodeFlags.HasAsyncFunctions)) {
-                writeLines(awaiterHelper);
-                if (languageVersion < ScriptTarget.ES2015) {
-                    writeLines(generatorHelper);
-                }
-
-                awaiterEmitted = true;
-                helpersEmitted = true;
             }
 
             if (helpersEmitted) {
@@ -2247,9 +2068,10 @@ const _super = (function (geti, seti) {
         }
 
         function writeLines(text: string): void {
-            const lines = text.split(/\r\n|\r|\n/g);
+            const lines = text.split(/\r\n?|\n/g);
+            const indentation = guessIndentation(lines);
             for (let i = 0; i < lines.length; i++) {
-                const line = lines[i];
+                const line = indentation ? lines[i].slice(indentation) : lines[i];
                 if (line.length) {
                     if (i > 0) {
                         writeLine();
@@ -2259,6 +2081,21 @@ const _super = (function (geti, seti) {
             }
         }
 
+        function guessIndentation(lines: string[]) {
+            let indentation: number;
+            for (const line of lines) {
+                for (let i = 0; i < line.length && (indentation === undefined || i < indentation); i++) {
+                    if (!isWhiteSpace(line.charCodeAt(i))) {
+                        if (indentation === undefined || i < indentation) {
+                            indentation = i;
+                            break;
+                        }
+                    }
+                }
+            }
+            return indentation;
+        }
+
         //
         // Helpers
         //
@@ -2300,8 +2137,8 @@ const _super = (function (geti, seti) {
             }
         }
 
-        function emitEmbeddedStatement(node: Statement) {
-            if (isBlock(node)) {
+        function emitEmbeddedStatement(parent: Node, node: Statement) {
+            if (isBlock(node) || getEmitFlags(parent) & EmitFlags.SingleLine) {
                 write(" ");
                 emit(node);
             }
@@ -2466,6 +2303,15 @@ const _super = (function (geti, seti) {
             }
         }
 
+        function writeLineOrSpace(node: Node) {
+            if (getEmitFlags(node) & EmitFlags.SingleLine) {
+                write(" ");
+            }
+            else {
+                writeLine();
+            }
+        }
+
         function writeIfAny(nodes: NodeArray<Node>, text: string) {
             if (nodes && nodes.length > 0) {
                 write(text);
@@ -2746,6 +2592,13 @@ const _super = (function (geti, seti) {
             return makeUniqueName("class");
         }
 
+        function generateNameForMethodOrAccessor(node: MethodDeclaration | AccessorDeclaration) {
+            if (isIdentifier(node.name)) {
+                return generateNameForNodeCached(node.name);
+            }
+            return makeTempVariableName(TempFlags.Auto);
+        }
+
         /**
          * Generates a unique name from a node.
          *
@@ -2767,6 +2620,10 @@ const _super = (function (geti, seti) {
                     return generateNameForExportDefault();
                 case SyntaxKind.ClassExpression:
                     return generateNameForClassExpression();
+                case SyntaxKind.MethodDeclaration:
+                case SyntaxKind.GetAccessor:
+                case SyntaxKind.SetAccessor:
+                    return generateNameForMethodOrAccessor(<MethodDeclaration | AccessorDeclaration>node);
                 default:
                     return makeTempVariableName(TempFlags.Auto);
             }
@@ -2817,6 +2674,11 @@ const _super = (function (geti, seti) {
             return node;
         }
 
+        function generateNameForNodeCached(node: Node) {
+            const nodeId = getNodeId(node);
+            return nodeIdToGeneratedName[nodeId] || (nodeIdToGeneratedName[nodeId] = unescapeIdentifier(generateNameForNode(node)));
+        }
+
         /**
          * Gets the generated identifier text from a generated identifier.
          *
@@ -2827,8 +2689,7 @@ const _super = (function (geti, seti) {
                 // Generated names generate unique names based on their original node
                 // and are cached based on that node's id
                 const node = getNodeForGeneratedName(name);
-                const nodeId = getNodeId(node);
-                return nodeIdToGeneratedName[nodeId] || (nodeIdToGeneratedName[nodeId] = unescapeIdentifier(generateNameForNode(node)));
+                return generateNameForNodeCached(node);
             }
             else {
                 // Auto, Loop, and Unique names are cached based on their unique

src/compiler/moduleNameResolver.ts

@@ -1,4 +1,4 @@
-/// <reference path="core.ts" />
+/// <reference path="core.ts" />
 /// <reference path="diagnosticInformationMap.generated.ts" />
 
 namespace ts {
@@ -14,6 +14,11 @@ namespace ts {
         return compilerOptions.traceResolution && host.trace !== undefined;
     }
 
+    /** Array that is only intended to be pushed to, never read. */
+    interface Push<T> {
+        push(value: T): void;
+    }
+
     /**
      * Result of trying to resolve a module.
      * At least one of `ts` and `js` should be defined, or the whole thing should be `undefined`.
@@ -27,7 +32,7 @@ namespace ts {
      * Kinds of file that we are currently looking for.
      * Typically there is one pass with Extensions.TypeScript, then a second pass with Extensions.JavaScript.
      */
-    const enum Extensions {
+    enum Extensions {
         TypeScript, /** '.ts', '.tsx', or '.d.ts' */
         JavaScript, /** '.js' or '.jsx' */
         DtsOnly /** Only '.d.ts' */
@@ -42,11 +47,6 @@ namespace ts {
         return resolved.path;
     }
 
-    /** Create Resolved from a file with unknown extension. */
-    function resolvedFromAnyFile(path: string): Resolved | undefined {
-        return { path, extension: extensionFromPath(path) };
-    }
-
     /** Adds `isExernalLibraryImport` to a Resolved to get a ResolvedModule. */
     function resolvedModuleFromResolved({ path, extension }: Resolved, isExternalLibraryImport: boolean): ResolvedModuleFull {
         return { resolvedFileName: path, extension, isExternalLibraryImport };
@@ -56,18 +56,18 @@ namespace ts {
         return { resolvedModule: resolved && resolvedModuleFromResolved(resolved, isExternalLibraryImport), failedLookupLocations };
     }
 
-    function moduleHasNonRelativeName(moduleName: string): boolean {
+    export function moduleHasNonRelativeName(moduleName: string): boolean {
         return !(isRootedDiskPath(moduleName) || isExternalModuleNameRelative(moduleName));
     }
 
     interface ModuleResolutionState {
         host: ModuleResolutionHost;
-        // We only use this subset of the compiler options.
-        compilerOptions: { rootDirs?: string[], baseUrl?: string, paths?: MapLike<string[]> };
+        compilerOptions: CompilerOptions;
         traceEnabled: boolean;
     }
 
-    function tryReadTypesSection(extensions: Extensions, packageJsonPath: string, baseDirectory: string, state: ModuleResolutionState): string {
+    /** Reads from "main" or "types"/"typings" depending on `extensions`. */
+    function tryReadPackageJsonMainOrTypes(extensions: Extensions, packageJsonPath: string, baseDirectory: string, state: ModuleResolutionState): string {
         const jsonContent = readJson(packageJsonPath, state.host);
 
         switch (extensions) {
@@ -128,7 +128,9 @@ namespace ts {
             currentDirectory = host.getCurrentDirectory();
         }
 
-        return currentDirectory !== undefined && getDefaultTypeRoots(currentDirectory, host);
+        if (currentDirectory !== undefined) {
+            return getDefaultTypeRoots(currentDirectory, host);
+        }
     }
 
     /**
@@ -142,20 +144,13 @@ namespace ts {
         }
 
         let typeRoots: string[];
-
-        while (true) {
-            const atTypes = combinePaths(currentDirectory, nodeModulesAtTypes);
+        forEachAncestorDirectory(currentDirectory, directory => {
+            const atTypes = combinePaths(directory, nodeModulesAtTypes);
             if (host.directoryExists(atTypes)) {
                 (typeRoots || (typeRoots = [])).push(atTypes);
             }
-
-            const parent = getDirectoryPath(currentDirectory);
-            if (parent === currentDirectory) {
-                break;
-            }
-            currentDirectory = parent;
-        }
-
+            return undefined;
+        });
         return typeRoots;
     }
     const nodeModulesAtTypes = combinePaths("node_modules", "@types");
@@ -195,63 +190,71 @@ namespace ts {
 
         const failedLookupLocations: string[] = [];
 
-        // Check primary library paths
-        if (typeRoots && typeRoots.length) {
+        let resolved = primaryLookup();
+        let primary = true;
+        if (!resolved) {
+            resolved = secondaryLookup();
+            primary = false;
+        }
+
+        let resolvedTypeReferenceDirective: ResolvedTypeReferenceDirective | undefined;
+        if (resolved) {
+            resolved = realpath(resolved, host, traceEnabled);
             if (traceEnabled) {
-                trace(host, Diagnostics.Resolving_with_primary_search_path_0, typeRoots.join(", "));
+                trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolved, primary);
             }
-            for (const typeRoot of typeRoots) {
-                const candidate = combinePaths(typeRoot, typeReferenceDirectiveName);
-                const candidateDirectory = getDirectoryPath(candidate);
+            resolvedTypeReferenceDirective = { primary, resolvedFileName: resolved };
+        }
 
-                const resolved = resolvedTypeScriptOnly(
-                    loadNodeModuleFromDirectory(Extensions.DtsOnly, candidate, failedLookupLocations,
-                        !directoryProbablyExists(candidateDirectory, host), moduleResolutionState));
+        return { resolvedTypeReferenceDirective, failedLookupLocations };
 
-                if (resolved) {
-                    if (traceEnabled) {
-                        trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolved, true);
+        function primaryLookup(): string | undefined {
+            // Check primary library paths
+            if (typeRoots && typeRoots.length) {
+                if (traceEnabled) {
+                    trace(host, Diagnostics.Resolving_with_primary_search_path_0, typeRoots.join(", "));
+                }
+                return forEach(typeRoots, typeRoot => {
+                    const candidate = combinePaths(typeRoot, typeReferenceDirectiveName);
+                    const candidateDirectory = getDirectoryPath(candidate);
+                    const directoryExists = directoryProbablyExists(candidateDirectory, host);
+                    if (!directoryExists && traceEnabled) {
+                        trace(host, Diagnostics.Directory_0_does_not_exist_skipping_all_lookups_in_it, candidateDirectory);
                     }
-                    return {
-                        resolvedTypeReferenceDirective: { primary: true, resolvedFileName: resolved },
-                        failedLookupLocations
-                    };
+                    return resolvedTypeScriptOnly(
+                        loadNodeModuleFromDirectory(Extensions.DtsOnly, candidate, failedLookupLocations,
+                            !directoryExists, moduleResolutionState));
+                });
+            }
+            else {
+                if (traceEnabled) {
+                    trace(host, Diagnostics.Root_directory_cannot_be_determined_skipping_primary_search_paths);
                 }
             }
         }
-        else {
-            if (traceEnabled) {
-                trace(host, Diagnostics.Root_directory_cannot_be_determined_skipping_primary_search_paths);
-            }
-        }
 
-        let resolvedFile: string;
-        const initialLocationForSecondaryLookup = containingFile && getDirectoryPath(containingFile);
+        function secondaryLookup(): string | undefined {
+            let resolvedFile: string;
+            const initialLocationForSecondaryLookup = containingFile && getDirectoryPath(containingFile);
 
-        if (initialLocationForSecondaryLookup !== undefined) {
-            // check secondary locations
-            if (traceEnabled) {
-                trace(host, Diagnostics.Looking_up_in_node_modules_folder_initial_location_0, initialLocationForSecondaryLookup);
-            }
-            resolvedFile = resolvedTypeScriptOnly(loadModuleFromNodeModules(Extensions.DtsOnly, typeReferenceDirectiveName, initialLocationForSecondaryLookup, failedLookupLocations, moduleResolutionState, /*checkOneLevel*/ false));
-            if (traceEnabled) {
-                if (resolvedFile) {
-                    trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolvedFile, false);
+            if (initialLocationForSecondaryLookup !== undefined) {
+                // check secondary locations
+                if (traceEnabled) {
+                    trace(host, Diagnostics.Looking_up_in_node_modules_folder_initial_location_0, initialLocationForSecondaryLookup);
                 }
-                else {
+                const result = loadModuleFromNodeModules(Extensions.DtsOnly, typeReferenceDirectiveName, initialLocationForSecondaryLookup, failedLookupLocations, moduleResolutionState, /*cache*/ undefined);
+                resolvedFile = resolvedTypeScriptOnly(result && result.value);
+                if (!resolvedFile && traceEnabled) {
                     trace(host, Diagnostics.Type_reference_directive_0_was_not_resolved, typeReferenceDirectiveName);
                 }
+                return resolvedFile;
+            }
+            else {
+                if (traceEnabled) {
+                    trace(host, Diagnostics.Containing_file_is_not_specified_and_root_directory_cannot_be_determined_skipping_lookup_in_node_modules_folder);
+                }
             }
         }
-        else {
-            if (traceEnabled) {
-                trace(host, Diagnostics.Containing_file_is_not_specified_and_root_directory_cannot_be_determined_skipping_lookup_in_node_modules_folder);
-            }
-        }
-        return {
-            resolvedTypeReferenceDirective: resolvedFile ? { primary: false, resolvedFileName: resolvedFile } : undefined,
-            failedLookupLocations
-        };
     }
 
     /**
@@ -292,33 +295,171 @@ namespace ts {
         return result;
     }
 
-    export function resolveModuleName(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
+    /**
+     * Cached module resolutions per containing directory.
+     * This assumes that any module id will have the same resolution for sibling files located in the same folder.
+     */
+    export interface ModuleResolutionCache extends NonRelativeModuleNameResolutionCache {
+        getOrCreateCacheForDirectory(directoryName: string): Map<ResolvedModuleWithFailedLookupLocations>;
+    }
+
+    /**
+     * Stored map from non-relative module name to a table: directory -> result of module lookup in this directory
+     * We support only non-relative module names because resolution of relative module names is usually more deterministic and thus less expensive.
+     */
+    export interface NonRelativeModuleNameResolutionCache {
+        getOrCreateCacheForModuleName(nonRelativeModuleName: string): PerModuleNameCache;
+    }
+
+    export interface PerModuleNameCache {
+        get(directory: string): ResolvedModuleWithFailedLookupLocations;
+        set(directory: string, result: ResolvedModuleWithFailedLookupLocations): void;
+    }
+
+    export function createModuleResolutionCache(currentDirectory: string, getCanonicalFileName: (s: string) => string): ModuleResolutionCache {
+        const directoryToModuleNameMap = createFileMap<Map<ResolvedModuleWithFailedLookupLocations>>();
+        const moduleNameToDirectoryMap = createMap<PerModuleNameCache>();
+
+        return { getOrCreateCacheForDirectory, getOrCreateCacheForModuleName };
+
+        function getOrCreateCacheForDirectory(directoryName: string) {
+            const path = toPath(directoryName, currentDirectory, getCanonicalFileName);
+            let perFolderCache = directoryToModuleNameMap.get(path);
+            if (!perFolderCache) {
+                perFolderCache = createMap<ResolvedModuleWithFailedLookupLocations>();
+                directoryToModuleNameMap.set(path, perFolderCache);
+            }
+            return perFolderCache;
+        }
+
+        function getOrCreateCacheForModuleName(nonRelativeModuleName: string) {
+            if (!moduleHasNonRelativeName(nonRelativeModuleName)) {
+                return undefined;
+            }
+            let perModuleNameCache = moduleNameToDirectoryMap[nonRelativeModuleName];
+            if (!perModuleNameCache) {
+                moduleNameToDirectoryMap[nonRelativeModuleName] = perModuleNameCache = createPerModuleNameCache();
+            }
+            return perModuleNameCache;
+        }
+
+        function createPerModuleNameCache(): PerModuleNameCache {
+            const directoryPathMap = createFileMap<ResolvedModuleWithFailedLookupLocations>();
+
+            return { get, set };
+
+            function get(directory: string): ResolvedModuleWithFailedLookupLocations {
+                return directoryPathMap.get(toPath(directory, currentDirectory, getCanonicalFileName));
+            }
+
+            /**
+             * At first this function add entry directory -> module resolution result to the table.
+             * Then it computes the set of parent folders for 'directory' that should have the same module resolution result
+             * and for every parent folder in set it adds entry: parent -> module resolution. .
+             * Lets say we first directory name: /a/b/c/d/e and resolution result is: /a/b/bar.ts.
+             * Set of parent folders that should have the same result will be: 
+             * [
+             *     /a/b/c/d, /a/b/c, /a/b
+             * ]
+             * this means that request for module resolution from file in any of these folder will be immediately found in cache.
+             */
+            function set(directory: string, result: ResolvedModuleWithFailedLookupLocations): void {
+                const path = toPath(directory, currentDirectory, getCanonicalFileName);
+                // if entry is already in cache do nothing
+                if (directoryPathMap.contains(path)) {
+                    return;
+                }
+                directoryPathMap.set(path, result);
+
+                const resolvedFileName = result.resolvedModule && result.resolvedModule.resolvedFileName;
+                // find common prefix between directory and resolved file name
+                // this common prefix should be the shorted path that has the same resolution
+                // directory: /a/b/c/d/e
+                // resolvedFileName: /a/b/foo.d.ts
+                const commonPrefix = getCommonPrefix(path, resolvedFileName);
+                let current = path;
+                while (true) {
+                    const parent = getDirectoryPath(current);
+                    if (parent === current || directoryPathMap.contains(parent)) {
+                        break;
+                    }
+                    directoryPathMap.set(parent, result);
+                    current = parent;
+
+                    if (current == commonPrefix) {
+                        break;
+                    }
+                }
+            }
+            
+            function getCommonPrefix(directory: Path, resolution: string) {
+                if (resolution === undefined) {
+                    return undefined;
+                }
+                const resolutionDirectory = toPath(getDirectoryPath(resolution), currentDirectory, getCanonicalFileName);
+
+                // find first position where directory and resolution differs
+                let i = 0;
+                while (i < Math.min(directory.length, resolutionDirectory.length) && directory.charCodeAt(i) === resolutionDirectory.charCodeAt(i)) {
+                    i++;
+                }
+
+                // find last directory separator before position i
+                const sep = directory.lastIndexOf(directorySeparator, i);
+                if (sep < 0) {
+                    return undefined;
+                }
+
+                return directory.substr(0, sep);
+            }
+        }
+    }
+
+    export function resolveModuleName(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, cache?: ModuleResolutionCache): ResolvedModuleWithFailedLookupLocations {
         const traceEnabled = isTraceEnabled(compilerOptions, host);
         if (traceEnabled) {
             trace(host, Diagnostics.Resolving_module_0_from_1, moduleName, containingFile);
         }
+        const containingDirectory = getDirectoryPath(containingFile);
+        let perFolderCache = cache && cache.getOrCreateCacheForDirectory(containingDirectory);
+        let result = perFolderCache && perFolderCache[moduleName];
 
-        let moduleResolution = compilerOptions.moduleResolution;
-        if (moduleResolution === undefined) {
-            moduleResolution = getEmitModuleKind(compilerOptions) === ModuleKind.CommonJS ? ModuleResolutionKind.NodeJs : ModuleResolutionKind.Classic;
+        if (result) {
             if (traceEnabled) {
-                trace(host, Diagnostics.Module_resolution_kind_is_not_specified_using_0, ModuleResolutionKind[moduleResolution]);
+                trace(host, Diagnostics.Resolution_for_module_0_was_found_in_cache, moduleName);
             }
         }
         else {
-            if (traceEnabled) {
-                trace(host, Diagnostics.Explicitly_specified_module_resolution_kind_Colon_0, ModuleResolutionKind[moduleResolution]);
+            let moduleResolution = compilerOptions.moduleResolution;
+            if (moduleResolution === undefined) {
+                moduleResolution = getEmitModuleKind(compilerOptions) === ModuleKind.CommonJS ? ModuleResolutionKind.NodeJs : ModuleResolutionKind.Classic;
+                if (traceEnabled) {
+                    trace(host, Diagnostics.Module_resolution_kind_is_not_specified_using_0, ModuleResolutionKind[moduleResolution]);
+                }
+            }
+            else {
+                if (traceEnabled) {
+                    trace(host, Diagnostics.Explicitly_specified_module_resolution_kind_Colon_0, ModuleResolutionKind[moduleResolution]);
+                }
             }
-        }
 
-        let result: ResolvedModuleWithFailedLookupLocations;
-        switch (moduleResolution) {
-            case ModuleResolutionKind.NodeJs:
-                result = nodeModuleNameResolver(moduleName, containingFile, compilerOptions, host);
-                break;
-            case ModuleResolutionKind.Classic:
-                result = classicNameResolver(moduleName, containingFile, compilerOptions, host);
-                break;
+            switch (moduleResolution) {
+                case ModuleResolutionKind.NodeJs:
+                    result = nodeModuleNameResolver(moduleName, containingFile, compilerOptions, host, cache);
+                    break;
+                case ModuleResolutionKind.Classic:
+                    result = classicNameResolver(moduleName, containingFile, compilerOptions, host, cache);
+                    break;
+            }
+
+            if (perFolderCache) {
+                perFolderCache[moduleName] = result;
+                // put result in per-module name cache
+                const perModuleNameCache = cache.getOrCreateCacheForModuleName(moduleName);
+                if (perModuleNameCache) {
+                    perModuleNameCache.set(containingDirectory, result);
+                }
+            }
         }
 
         if (traceEnabled) {
@@ -341,7 +482,7 @@ namespace ts {
      * 'typings' entry or file 'index' with some supported extension
      * - Classic loader will only try to interpret '/a/b/c' as file.
      */
-    type ResolutionKindSpecificLoader = (extensions: Extensions, candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState) => Resolved | undefined;
+    type ResolutionKindSpecificLoader = (extensions: Extensions, candidate: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState) => Resolved | undefined;
 
     /**
      * Any module resolution kind can be augmented with optional settings: 'baseUrl', 'paths' and 'rootDirs' - they are used to
@@ -404,7 +545,7 @@ namespace ts {
      * entries in 'rootDirs', use them to build absolute path out of (*) and try to resolve module from this location.
      */
     function tryLoadModuleUsingOptionalResolutionSettings(extensions: Extensions, moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
-        failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
+        failedLookupLocations: Push<string>, state: ModuleResolutionState): Resolved | undefined {
 
         if (moduleHasNonRelativeName(moduleName)) {
             return tryLoadModuleUsingBaseUrl(extensions, moduleName, loader, failedLookupLocations, state);
@@ -415,7 +556,7 @@ namespace ts {
     }
 
     function tryLoadModuleUsingRootDirs(extensions: Extensions, moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
-        failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
+        failedLookupLocations: Push<string>, state: ModuleResolutionState): Resolved | undefined {
 
         if (!state.compilerOptions.rootDirs) {
             return undefined;
@@ -491,7 +632,7 @@ namespace ts {
         return undefined;
     }
 
-    function tryLoadModuleUsingBaseUrl(extensions: Extensions, moduleName: string, loader: ResolutionKindSpecificLoader, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
+    function tryLoadModuleUsingBaseUrl(extensions: Extensions, moduleName: string, loader: ResolutionKindSpecificLoader, failedLookupLocations: Push<string>, state: ModuleResolutionState): Resolved | undefined {
         if (!state.compilerOptions.baseUrl) {
             return undefined;
         }
@@ -514,18 +655,21 @@ namespace ts {
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.Module_name_0_matched_pattern_1, moduleName, matchedPatternText);
             }
-            for (const subst of state.compilerOptions.paths[matchedPatternText]) {
+            return forEach(state.compilerOptions.paths[matchedPatternText], subst => {
                 const path = matchedStar ? subst.replace("*", matchedStar) : subst;
                 const candidate = normalizePath(combinePaths(state.compilerOptions.baseUrl, path));
                 if (state.traceEnabled) {
                     trace(state.host, Diagnostics.Trying_substitution_0_candidate_module_location_Colon_1, subst, path);
                 }
-                const resolved = loader(extensions, candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
-                if (resolved) {
-                    return resolved;
+                // A path mapping may have a ".ts" extension; in contrast to an import, which should omit it.
+                const tsExtension = tryGetExtensionFromPath(candidate);
+                if (tsExtension !== undefined) {
+                    const path = tryFile(candidate, failedLookupLocations, /*onlyRecordFailures*/false, state);
+                    return path && { path, extension: tsExtension };
                 }
-            }
-            return undefined;
+
+                return loader(extensions, candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
+            });
         }
         else {
             const candidate = normalizePath(combinePaths(state.compilerOptions.baseUrl, moduleName));
@@ -538,7 +682,7 @@ namespace ts {
         }
     }
 
-    export function nodeModuleNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
+    export function nodeModuleNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, cache?: ModuleResolutionCache): ResolvedModuleWithFailedLookupLocations {
         const containingDirectory = getDirectoryPath(containingFile);
         const traceEnabled = isTraceEnabled(compilerOptions, host);
 
@@ -546,52 +690,75 @@ namespace ts {
         const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
 
         const result = tryResolve(Extensions.TypeScript) || tryResolve(Extensions.JavaScript);
-        if (result) {
-            const { resolved, isExternalLibraryImport } = result;
-            return createResolvedModuleWithFailedLookupLocations(resolved && resolvedWithRealpath(resolved, host, traceEnabled), isExternalLibraryImport, failedLookupLocations);
+        if (result && result.value) {
+            const { resolved, isExternalLibraryImport } = result.value;
+            return createResolvedModuleWithFailedLookupLocations(resolved, isExternalLibraryImport, failedLookupLocations);
         }
         return { resolvedModule: undefined, failedLookupLocations };
 
-        function tryResolve(extensions: Extensions): { resolved: Resolved, isExternalLibraryImport: boolean } | undefined {
+        function tryResolve(extensions: Extensions): SearchResult<{ resolved: Resolved, isExternalLibraryImport: boolean }> {
             const resolved = tryLoadModuleUsingOptionalResolutionSettings(extensions, moduleName, containingDirectory, nodeLoadModuleByRelativeName, failedLookupLocations, state);
             if (resolved) {
-                return { resolved, isExternalLibraryImport: false };
+                return toSearchResult({ resolved, isExternalLibraryImport: false });
             }
 
             if (moduleHasNonRelativeName(moduleName)) {
                 if (traceEnabled) {
-                    trace(host, Diagnostics.Loading_module_0_from_node_modules_folder, moduleName);
+                    trace(host, Diagnostics.Loading_module_0_from_node_modules_folder_target_file_type_1, moduleName, Extensions[extensions]);
                 }
-                const resolved = loadModuleFromNodeModules(extensions, moduleName, containingDirectory, failedLookupLocations, state, /*checkOneLevel*/ false);
-                return resolved && { resolved, isExternalLibraryImport: true };
+                const resolved = loadModuleFromNodeModules(extensions, moduleName, containingDirectory, failedLookupLocations, state, cache);
+                // For node_modules lookups, get the real path so that multiple accesses to an `npm link`-ed module do not create duplicate files.
+                return resolved && { value: resolved.value && { resolved: { path: realpath(resolved.value.path, host, traceEnabled), extension: resolved.value.extension }, isExternalLibraryImport: true } };
             }
             else {
                 const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
                 const resolved = nodeLoadModuleByRelativeName(extensions, candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
-                return resolved && { resolved, isExternalLibraryImport: false };
+                return resolved && toSearchResult({ resolved, isExternalLibraryImport: false });
             }
         }
     }
 
-    function resolvedWithRealpath(resolved: Resolved, host: ModuleResolutionHost, traceEnabled: boolean): Resolved {
+    function realpath(path: string, host: ModuleResolutionHost, traceEnabled: boolean): string {
         if (!host.realpath) {
-            return resolved;
+            return path;
         }
 
-        const real = normalizePath(host.realpath(resolved.path));
+        const real = normalizePath(host.realpath(path));
         if (traceEnabled) {
-            trace(host, Diagnostics.Resolving_real_path_for_0_result_1, resolved.path, real);
+            trace(host, Diagnostics.Resolving_real_path_for_0_result_1, path, real);
         }
-        return { path: real, extension: resolved.extension };
+        return real;
     }
 
-    function nodeLoadModuleByRelativeName(extensions: Extensions, candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
+    function nodeLoadModuleByRelativeName(extensions: Extensions, candidate: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         if (state.traceEnabled) {
-            trace(state.host, Diagnostics.Loading_module_as_file_Slash_folder_candidate_module_location_0, candidate);
+            trace(state.host, Diagnostics.Loading_module_as_file_Slash_folder_candidate_module_location_0_target_file_type_1, candidate, Extensions[extensions]);
         }
-
-        const resolvedFromFile = !pathEndsWithDirectorySeparator(candidate) && loadModuleFromFile(extensions, candidate, failedLookupLocations, onlyRecordFailures, state);
-        return resolvedFromFile || loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, onlyRecordFailures, state);
+        if (!pathEndsWithDirectorySeparator(candidate)) {
+            if (!onlyRecordFailures) {
+                const parentOfCandidate = getDirectoryPath(candidate);
+                if (!directoryProbablyExists(parentOfCandidate, state.host)) {
+                    if (state.traceEnabled) {
+                        trace(state.host, Diagnostics.Directory_0_does_not_exist_skipping_all_lookups_in_it, parentOfCandidate);
+                    }
+                    onlyRecordFailures = true;
+                }
+            }
+            const resolvedFromFile = loadModuleFromFile(extensions, candidate, failedLookupLocations, onlyRecordFailures, state);
+            if (resolvedFromFile) {
+                return resolvedFromFile;
+            }
+        }
+        if (!onlyRecordFailures) {
+            const candidateExists = directoryProbablyExists(candidate, state.host);
+            if (!candidateExists) {
+                if (state.traceEnabled) {
+                    trace(state.host, Diagnostics.Directory_0_does_not_exist_skipping_all_lookups_in_it, candidate);
+                }
+                onlyRecordFailures = true;
+            }
+        }
+        return loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, onlyRecordFailures, state);
     }
 
     /* @internal */
@@ -604,7 +771,7 @@ namespace ts {
      * @param {boolean} onlyRecordFailures - if true then function won't try to actually load files but instead record all attempts as failures. This flag is necessary
      * in cases when we know upfront that all load attempts will fail (because containing folder does not exists) however we still need to record all failed lookup locations.
      */
-    function loadModuleFromFile(extensions: Extensions, candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
+    function loadModuleFromFile(extensions: Extensions, candidate: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         // First, try adding an extension. An import of "foo" could be matched by a file "foo.ts", or "foo.js" by "foo.js.ts"
         const resolvedByAddingExtension = tryAddingExtensions(candidate, extensions, failedLookupLocations, onlyRecordFailures, state);
         if (resolvedByAddingExtension) {
@@ -624,7 +791,7 @@ namespace ts {
     }
 
     /** Try to return an existing file that adds one of the `extensions` to `candidate`. */
-    function tryAddingExtensions(candidate: string, extensions: Extensions, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
+    function tryAddingExtensions(candidate: string, extensions: Extensions, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         if (!onlyRecordFailures) {
             // check if containing folder exists - if it doesn't then just record failures for all supported extensions without disk probing
             const directory = getDirectoryPath(candidate);
@@ -649,23 +816,25 @@ namespace ts {
     }
 
     /** Return the file if it exists. */
-    function tryFile(fileName: string, failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
-        if (!onlyRecordFailures && state.host.fileExists(fileName)) {
-            if (state.traceEnabled) {
-                trace(state.host, Diagnostics.File_0_exist_use_it_as_a_name_resolution_result, fileName);
+    function tryFile(fileName: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
+        if (!onlyRecordFailures) {
+            if (state.host.fileExists(fileName)) {
+                if (state.traceEnabled) {
+                    trace(state.host, Diagnostics.File_0_exist_use_it_as_a_name_resolution_result, fileName);
+                }
+                return fileName;
             }
-            return fileName;
-        }
-        else {
-            if (state.traceEnabled) {
-                trace(state.host, Diagnostics.File_0_does_not_exist, fileName);
+            else {
+                if (state.traceEnabled) {
+                    trace(state.host, Diagnostics.File_0_does_not_exist, fileName);
+                }
             }
-            failedLookupLocation.push(fileName);
-            return undefined;
         }
+        failedLookupLocations.push(fileName);
+        return undefined;
     }
 
-    function loadNodeModuleFromDirectory(extensions: Extensions, candidate: string, failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
+    function loadNodeModuleFromDirectory(extensions: Extensions, candidate: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         const packageJsonPath = pathToPackageJson(candidate);
         const directoryExists = !onlyRecordFailures && directoryProbablyExists(candidate, state.host);
 
@@ -673,18 +842,23 @@ namespace ts {
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.Found_package_json_at_0, packageJsonPath);
             }
-            const typesFile = tryReadTypesSection(extensions, packageJsonPath, candidate, state);
-            if (typesFile) {
-                const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(typesFile), state.host);
+            const mainOrTypesFile = tryReadPackageJsonMainOrTypes(extensions, packageJsonPath, candidate, state);
+            if (mainOrTypesFile) {
+                const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(mainOrTypesFile), state.host);
                 // A package.json "typings" may specify an exact filename, or may choose to omit an extension.
-                const fromFile = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state);
-                if (fromFile) {
-                    // Note: this would allow a package.json to specify a ".js" file as typings. Maybe that should be forbidden.
-                    return resolvedFromAnyFile(fromFile);
+                const fromExactFile = tryFile(mainOrTypesFile, failedLookupLocations, onlyRecordFailures, state);
+                if (fromExactFile) {
+                    const resolved = fromExactFile && resolvedIfExtensionMatches(extensions, fromExactFile);
+                    if (resolved) {
+                        return resolved;
+                    }
+                    if (state.traceEnabled) {
+                        trace(state.host, Diagnostics.File_0_has_an_unsupported_extension_so_skipping_it, fromExactFile);
+                    }
                 }
-                const x = tryAddingExtensions(typesFile, Extensions.TypeScript, failedLookupLocation, onlyRecordFailures, state);
-                if (x) {
-                    return x;
+                const resolved = tryAddingExtensions(mainOrTypesFile, Extensions.TypeScript, failedLookupLocations, onlyRecordFailures, state);
+                if (resolved) {
+                    return resolved;
                 }
             }
             else {
@@ -694,77 +868,127 @@ namespace ts {
             }
         }
         else {
-            if (state.traceEnabled) {
+            if (directoryExists && state.traceEnabled) {
                 trace(state.host, Diagnostics.File_0_does_not_exist, packageJsonPath);
             }
             // record package json as one of failed lookup locations - in the future if this file will appear it will invalidate resolution results
-            failedLookupLocation.push(packageJsonPath);
+            failedLookupLocations.push(packageJsonPath);
         }
 
-        return loadModuleFromFile(extensions, combinePaths(candidate, "index"), failedLookupLocation, !directoryExists, state);
+        return loadModuleFromFile(extensions, combinePaths(candidate, "index"), failedLookupLocations, !directoryExists, state);
+    }
+
+    /** Resolve from an arbitrarily specified file. Return `undefined` if it has an unsupported extension. */
+    function resolvedIfExtensionMatches(extensions: Extensions, path: string): Resolved | undefined {
+        const extension = tryGetExtensionFromPath(path);
+        return extension !== undefined && extensionIsOk(extensions, extension) ? { path, extension } : undefined;
+    }
+
+    /** True if `extension` is one of the supported `extensions`. */
+    function extensionIsOk(extensions: Extensions, extension: Extension): boolean {
+        switch (extensions) {
+            case Extensions.JavaScript:
+                return extension === Extension.Js || extension === Extension.Jsx;
+            case Extensions.TypeScript:
+                return extension === Extension.Ts || extension === Extension.Tsx || extension === Extension.Dts;
+            case Extensions.DtsOnly:
+                return extension === Extension.Dts;
+        }
     }
 
     function pathToPackageJson(directory: string): string {
         return combinePaths(directory, "package.json");
     }
 
-    function loadModuleFromNodeModulesFolder(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
-        const nodeModulesFolder = combinePaths(directory, "node_modules");
-        const nodeModulesFolderExists = directoryProbablyExists(nodeModulesFolder, state.host);
+    function loadModuleFromNodeModulesFolder(extensions: Extensions, moduleName: string, nodeModulesFolder: string, nodeModulesFolderExists: boolean, failedLookupLocations: Push<string>, state: ModuleResolutionState): Resolved | undefined {
         const candidate = normalizePath(combinePaths(nodeModulesFolder, moduleName));
 
         return loadModuleFromFile(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state) ||
             loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
     }
 
-    function loadModuleFromNodeModules(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean): Resolved | undefined {
-        return loadModuleFromNodeModulesWorker(extensions, moduleName, directory, failedLookupLocations, state, checkOneLevel, /*typesOnly*/ false);
+    function loadModuleFromNodeModules(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, cache: NonRelativeModuleNameResolutionCache): SearchResult<Resolved> {
+        return loadModuleFromNodeModulesWorker(extensions, moduleName, directory, failedLookupLocations, state, /*typesOnly*/ false, cache);
     }
-    function loadModuleFromNodeModulesAtTypes(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
-        return loadModuleFromNodeModulesWorker(Extensions.TypeScript, moduleName, directory, failedLookupLocations, state, /*checkOneLevel*/ false, /*typesOnly*/ true);
+    function loadModuleFromNodeModulesAtTypes(moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState): SearchResult<Resolved> {
+        // Extensions parameter here doesn't actually matter, because typesOnly ensures we're just doing @types lookup, which is always DtsOnly.
+        return loadModuleFromNodeModulesWorker(Extensions.DtsOnly, moduleName, directory, failedLookupLocations, state, /*typesOnly*/ true, /*cache*/ undefined);
     }
 
-    function loadModuleFromNodeModulesWorker(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean, typesOnly: boolean): Resolved | undefined {
-        directory = normalizeSlashes(directory);
-        while (true) {
-            if (getBaseFileName(directory) !== "node_modules") {
-                const resolved = tryInDirectory();
-                if (resolved) {
-                    return resolved;
+    function loadModuleFromNodeModulesWorker(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, typesOnly: boolean, cache: NonRelativeModuleNameResolutionCache): SearchResult<Resolved> {
+        const perModuleNameCache = cache && cache.getOrCreateCacheForModuleName(moduleName);
+        return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+            if (getBaseFileName(ancestorDirectory) !== "node_modules") {
+                const resolutionFromCache = tryFindNonRelativeModuleNameInCache(perModuleNameCache, moduleName, ancestorDirectory, state.traceEnabled, state.host);
+                if (resolutionFromCache) {
+                    return resolutionFromCache;
                 }
+                return toSearchResult(loadModuleFromNodeModulesOneLevel(extensions, moduleName, ancestorDirectory, failedLookupLocations, state, typesOnly));
             }
+        });
+    }
 
-            const parentPath = getDirectoryPath(directory);
-            if (parentPath === directory || checkOneLevel) {
-                return undefined;
-            }
-
-            directory = parentPath;
+    /** Load a module from a single node_modules directory, but not from any ancestors' node_modules directories. */
+    function loadModuleFromNodeModulesOneLevel(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, typesOnly = false): Resolved | undefined {
+        const nodeModulesFolder = combinePaths(directory, "node_modules");
+        const nodeModulesFolderExists = directoryProbablyExists(nodeModulesFolder, state.host);
+        if (!nodeModulesFolderExists && state.traceEnabled) {
+            trace(state.host, Diagnostics.Directory_0_does_not_exist_skipping_all_lookups_in_it, nodeModulesFolder);
         }
 
-        function tryInDirectory(): Resolved | undefined {
-            const packageResult = typesOnly ? undefined : loadModuleFromNodeModulesFolder(extensions, moduleName, directory, failedLookupLocations, state);
-            return packageResult || loadModuleFromNodeModulesFolder(extensions, combinePaths("@types", moduleName), directory, failedLookupLocations, state);
+        const packageResult = typesOnly ? undefined : loadModuleFromNodeModulesFolder(extensions, moduleName, nodeModulesFolder, nodeModulesFolderExists, failedLookupLocations, state);
+        if (packageResult) {
+            return packageResult;
+        }
+        if (extensions !== Extensions.JavaScript) {
+            const nodeModulesAtTypes = combinePaths(nodeModulesFolder, "@types");
+            let nodeModulesAtTypesExists = nodeModulesFolderExists;
+            if (nodeModulesFolderExists && !directoryProbablyExists(nodeModulesAtTypes, state.host)) {
+                if (state.traceEnabled) {
+                    trace(state.host, Diagnostics.Directory_0_does_not_exist_skipping_all_lookups_in_it, nodeModulesAtTypes);
+                }
+                nodeModulesAtTypesExists = false;
+            }
+            return loadModuleFromNodeModulesFolder(Extensions.DtsOnly, moduleName, nodeModulesAtTypes, nodeModulesAtTypesExists, failedLookupLocations, state);
         }
     }
 
-    export function classicNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
+    function tryFindNonRelativeModuleNameInCache(cache: PerModuleNameCache | undefined, moduleName: string, containingDirectory: string, traceEnabled: boolean, host: ModuleResolutionHost): SearchResult<Resolved> {
+        const result = cache && cache.get(containingDirectory);
+        if (result) {
+            if (traceEnabled) {
+                trace(host, Diagnostics.Resolution_for_module_0_was_found_in_cache, moduleName)
+            }
+            return { value: result.resolvedModule && { path: result.resolvedModule.resolvedFileName, extension: result.resolvedModule.extension } };
+        }
+    }
+
+    export function classicNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, cache?: NonRelativeModuleNameResolutionCache): ResolvedModuleWithFailedLookupLocations {
         const traceEnabled = isTraceEnabled(compilerOptions, host);
         const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
         const failedLookupLocations: string[] = [];
         const containingDirectory = getDirectoryPath(containingFile);
 
         const resolved = tryResolve(Extensions.TypeScript) || tryResolve(Extensions.JavaScript);
-        return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ false, failedLookupLocations);
+        return createResolvedModuleWithFailedLookupLocations(resolved && resolved.value, /*isExternalLibraryImport*/ false, failedLookupLocations);
 
-        function tryResolve(extensions: Extensions): Resolved | undefined {
+        function tryResolve(extensions: Extensions): SearchResult<Resolved> {
             const resolvedUsingSettings = tryLoadModuleUsingOptionalResolutionSettings(extensions, moduleName, containingDirectory, loadModuleFromFile, failedLookupLocations, state);
             if (resolvedUsingSettings) {
-                return resolvedUsingSettings;
+                return { value: resolvedUsingSettings };
             }
+            const perModuleNameCache = cache && cache.getOrCreateCacheForModuleName(moduleName);
 
             if (moduleHasNonRelativeName(moduleName)) {
-                const resolved = loadModuleFromAncestorDirectories(extensions, moduleName, containingDirectory, failedLookupLocations, state);
+                // Climb up parent directories looking for a module.
+                const resolved = forEachAncestorDirectory(containingDirectory, directory => {
+                    const resolutionFromCache = tryFindNonRelativeModuleNameInCache(perModuleNameCache, moduleName, directory, traceEnabled, host);
+                    if (resolutionFromCache) {
+                        return resolutionFromCache;
+                    }
+                    const searchName = normalizePath(combinePaths(directory, moduleName));
+                    return toSearchResult(loadModuleFromFile(extensions, searchName, failedLookupLocations, /*onlyRecordFailures*/ false, state));
+                });
                 if (resolved) {
                     return resolved;
                 }
@@ -775,27 +999,11 @@ namespace ts {
             }
             else {
                 const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
-                return loadModuleFromFile(extensions, candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+                return toSearchResult(loadModuleFromFile(extensions, candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state));
             }
         }
     }
 
-    /** Climb up parent directories looking for a module. */
-    function loadModuleFromAncestorDirectories(extensions: Extensions, moduleName: string, containingDirectory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
-        while (true) {
-            const searchName = normalizePath(combinePaths(containingDirectory, moduleName));
-            const referencedSourceFile = loadModuleFromFile(extensions, searchName, failedLookupLocations, /*onlyRecordFailures*/ false, state);
-            if (referencedSourceFile) {
-                return referencedSourceFile;
-            }
-            const parentPath = getDirectoryPath(containingDirectory);
-            if (parentPath === containingDirectory) {
-                return undefined;
-            }
-            containingDirectory = parentPath;
-        }
-    }
-
     /**
      * LSHost may load a module from a global cache of typings.
      * This is the minumum code needed to expose that functionality; the rest is in LSHost.
@@ -808,8 +1016,44 @@ namespace ts {
         }
         const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
         const failedLookupLocations: string[] = [];
-        const resolved = loadModuleFromNodeModules(Extensions.TypeScript, moduleName, globalCache, failedLookupLocations, state, /*checkOneLevel*/ true) ||
-            loadModuleFromNodeModules(Extensions.JavaScript, moduleName, globalCache, failedLookupLocations, state, /*checkOneLevel*/ true);
+        const resolved = loadModuleFromNodeModulesOneLevel(Extensions.DtsOnly, moduleName, globalCache, failedLookupLocations, state);
         return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ true, failedLookupLocations);
     }
+
+    /**
+     * Represents result of search. Normally when searching among several alternatives we treat value `undefined` as indicator
+     * that search fails and we should try another option. 
+     * However this does not allow us to represent final result that should be used instead of further searching (i.e. a final result that was found in cache).
+     * SearchResult is used to deal with this issue, its values represents following outcomes:
+     * - undefined - not found, continue searching
+     * - { value: undefined } - not found - stop searching
+     * - { value: <some-value> } - found - stop searching
+     */
+    type SearchResult<T> = { value: T | undefined } | undefined;
+    
+    /**
+     * Wraps value to SearchResult.
+     * @returns undefined if value is undefined or { value } otherwise
+     */
+    function toSearchResult<T>(value: T | undefined): SearchResult<T> {
+        return value !== undefined ? { value } : undefined;
+    }
+
+
+    /** Calls `callback` on `directory` and every ancestor directory it has, returning the first defined result. */
+    function forEachAncestorDirectory<T>(directory: string, callback: (directory: string) => SearchResult<T>): SearchResult<T> {
+        while (true) {
+            const result = callback(directory);
+            if (result !== undefined) {
+                return result;
+            }
+
+            const parentPath = getDirectoryPath(directory);
+            if (parentPath === directory) {
+                return undefined;
+            }
+
+            directory = parentPath;
+        }
+    }
 }

src/compiler/parser.ts

@@ -74,6 +74,8 @@ namespace ts {
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).questionToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).equalsToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).objectAssignmentInitializer);
+            case SyntaxKind.SpreadAssignment:
+                return visitNode(cbNode, (<SpreadAssignment>node).expression);
             case SyntaxKind.Parameter:
             case SyntaxKind.PropertyDeclaration:
             case SyntaxKind.PropertySignature:
@@ -139,6 +141,11 @@ namespace ts {
             case SyntaxKind.IndexedAccessType:
                 return visitNode(cbNode, (<IndexedAccessTypeNode>node).objectType) ||
                     visitNode(cbNode, (<IndexedAccessTypeNode>node).indexType);
+            case SyntaxKind.MappedType:
+                return visitNode(cbNode, (<MappedTypeNode>node).readonlyToken) ||
+                    visitNode(cbNode, (<MappedTypeNode>node).typeParameter) ||
+                    visitNode(cbNode, (<MappedTypeNode>node).questionToken) ||
+                    visitNode(cbNode, (<MappedTypeNode>node).type);
             case SyntaxKind.LiteralType:
                 return visitNode(cbNode, (<LiteralTypeNode>node).literal);
             case SyntaxKind.ObjectBindingPattern:
@@ -191,14 +198,16 @@ namespace ts {
                     visitNode(cbNode, (<AsExpression>node).type);
             case SyntaxKind.NonNullExpression:
                 return visitNode(cbNode, (<NonNullExpression>node).expression);
+            case SyntaxKind.MetaProperty:
+                return visitNode(cbNode, (<MetaProperty>node).name);
             case SyntaxKind.ConditionalExpression:
                 return visitNode(cbNode, (<ConditionalExpression>node).condition) ||
                     visitNode(cbNode, (<ConditionalExpression>node).questionToken) ||
                     visitNode(cbNode, (<ConditionalExpression>node).whenTrue) ||
                     visitNode(cbNode, (<ConditionalExpression>node).colonToken) ||
                     visitNode(cbNode, (<ConditionalExpression>node).whenFalse);
-            case SyntaxKind.SpreadElementExpression:
-                return visitNode(cbNode, (<SpreadElementExpression>node).expression);
+            case SyntaxKind.SpreadElement:
+                return visitNode(cbNode, (<SpreadElement>node).expression);
             case SyntaxKind.Block:
             case SyntaxKind.ModuleBlock:
                 return visitNodes(cbNodes, (<Block>node).statements);
@@ -366,7 +375,8 @@ namespace ts {
             case SyntaxKind.JsxSpreadAttribute:
                 return visitNode(cbNode, (<JsxSpreadAttribute>node).expression);
             case SyntaxKind.JsxExpression:
-                return visitNode(cbNode, (<JsxExpression>node).expression);
+                return visitNode(cbNode, (node as JsxExpression).dotDotDotToken) ||
+                    visitNode(cbNode, (node as JsxExpression).expression);
             case SyntaxKind.JsxClosingElement:
                 return visitNode(cbNode, (<JsxClosingElement>node).tagName);
 
@@ -411,6 +421,8 @@ namespace ts {
                 return visitNode(cbNode, (<JSDocReturnTag>node).typeExpression);
             case SyntaxKind.JSDocTypeTag:
                 return visitNode(cbNode, (<JSDocTypeTag>node).typeExpression);
+            case SyntaxKind.JSDocAugmentsTag:
+                return visitNode(cbNode, (<JSDocAugmentsTag>node).typeExpression);
             case SyntaxKind.JSDocTemplateTag:
                 return visitNodes(cbNodes, (<JSDocTemplateTag>node).typeParameters);
             case SyntaxKind.JSDocTypedefTag:
@@ -438,6 +450,10 @@ namespace ts {
         return result;
     }
 
+    export function parseIsolatedEntityName(text: string, languageVersion: ScriptTarget): EntityName {
+        return Parser.parseIsolatedEntityName(text, languageVersion);
+    }
+
     export function isExternalModule(file: SourceFile): boolean {
         return file.externalModuleIndicator !== undefined;
     }
@@ -589,6 +605,16 @@ namespace ts {
             return result;
         }
 
+        export function parseIsolatedEntityName(content: string, languageVersion: ScriptTarget): EntityName {
+            initializeState(content, languageVersion, /*syntaxCursor*/ undefined, ScriptKind.JS);
+            // Prime the scanner.
+            nextToken();
+            const entityName = parseEntityName(/*allowReservedWords*/ true);
+            const isInvalid = token() === SyntaxKind.EndOfFileToken && !parseDiagnostics.length;
+            clearState();
+            return isInvalid ? entityName : undefined;
+        }
+
         function getLanguageVariant(scriptKind: ScriptKind) {
             // .tsx and .jsx files are treated as jsx language variant.
             return scriptKind === ScriptKind.TSX || scriptKind === ScriptKind.JSX || scriptKind === ScriptKind.JS ? LanguageVariant.JSX : LanguageVariant.Standard;
@@ -660,7 +686,7 @@ namespace ts {
 
 
         function addJSDocComment<T extends Node>(node: T): T {
-            const comments = getJsDocCommentsFromText(node, sourceFile.text);
+            const comments = getJSDocCommentRanges(node, sourceFile.text);
             if (comments) {
                 for (const comment of comments) {
                     const jsDoc = JSDocParser.parseJSDocComment(node, comment.pos, comment.end - comment.pos);
@@ -668,10 +694,10 @@ namespace ts {
                         continue;
                     }
 
-                    if (!node.jsDocComments) {
-                        node.jsDocComments = [];
+                    if (!node.jsDoc) {
+                        node.jsDoc = [];
                     }
-                    node.jsDocComments.push(jsDoc);
+                    node.jsDoc.push(jsDoc);
                 }
             }
 
@@ -698,11 +724,11 @@ namespace ts {
                     const saveParent = parent;
                     parent = n;
                     forEachChild(n, visitNode);
-                    if (n.jsDocComments) {
-                        for (const jsDocComment of n.jsDocComments) {
-                            jsDocComment.parent = n;
-                            parent = jsDocComment;
-                            forEachChild(jsDocComment, visitNode);
+                    if (n.jsDoc) {
+                        for (const jsDoc of n.jsDoc) {
+                            jsDoc.parent = n;
+                            parent = jsDoc;
+                            forEachChild(jsDoc, visitNode);
                         }
                     }
                     parent = saveParent;
@@ -1147,7 +1173,7 @@ namespace ts {
 
         function parsePropertyNameWorker(allowComputedPropertyNames: boolean): PropertyName {
             if (token() === SyntaxKind.StringLiteral || token() === SyntaxKind.NumericLiteral) {
-                return parseLiteralNode(/*internName*/ true);
+                return <StringLiteral | NumericLiteral>parseLiteralNode(/*internName*/ true);
             }
             if (allowComputedPropertyNames && token() === SyntaxKind.OpenBracketToken) {
                 return parseComputedPropertyName();
@@ -1269,9 +1295,11 @@ namespace ts {
                     // which would be a candidate for improved error reporting.
                     return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
                 case ParsingContext.ObjectLiteralMembers:
-                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.AsteriskToken || isLiteralPropertyName();
+                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.AsteriskToken || token() === SyntaxKind.DotDotDotToken || isLiteralPropertyName();
+                case ParsingContext.RestProperties:
+                    return isLiteralPropertyName();
                 case ParsingContext.ObjectBindingElements:
-                    return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
+                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.DotDotDotToken || isLiteralPropertyName();
                 case ParsingContext.HeritageClauseElement:
                     // If we see { } then only consume it as an expression if it is followed by , or {
                     // That way we won't consume the body of a class in its heritage clause.
@@ -1398,6 +1426,7 @@ namespace ts {
                 case ParsingContext.ArrayBindingElements:
                     return token() === SyntaxKind.CloseBracketToken;
                 case ParsingContext.Parameters:
+                case ParsingContext.RestProperties:
                     // Tokens other than ')' and ']' (the latter for index signatures) are here for better error recovery
                     return token() === SyntaxKind.CloseParenToken || token() === SyntaxKind.CloseBracketToken /*|| token === SyntaxKind.OpenBraceToken*/;
                 case ParsingContext.TypeArguments:
@@ -1583,6 +1612,9 @@ namespace ts {
                 case ParsingContext.Parameters:
                     return isReusableParameter(node);
 
+                case ParsingContext.RestProperties:
+                    return false;
+
                 // Any other lists we do not care about reusing nodes in.  But feel free to add if
                 // you can do so safely.  Danger areas involve nodes that may involve speculative
                 // parsing.  If speculative parsing is involved with the node, then the range the
@@ -1649,8 +1681,8 @@ namespace ts {
                         // Method declarations are not necessarily reusable.  An object-literal
                         // may have a method calls "constructor(...)" and we must reparse that
                         // into an actual .ConstructorDeclaration.
-                        let methodDeclaration = <MethodDeclaration>node;
-                        let nameIsConstructor = methodDeclaration.name.kind === SyntaxKind.Identifier &&
+                        const methodDeclaration = <MethodDeclaration>node;
+                        const nameIsConstructor = methodDeclaration.name.kind === SyntaxKind.Identifier &&
                             (<Identifier>methodDeclaration.name).originalKeywordKind === SyntaxKind.ConstructorKeyword;
 
                         return !nameIsConstructor;
@@ -1780,6 +1812,7 @@ namespace ts {
                 case ParsingContext.BlockStatements: return Diagnostics.Declaration_or_statement_expected;
                 case ParsingContext.SwitchClauses: return Diagnostics.case_or_default_expected;
                 case ParsingContext.SwitchClauseStatements: return Diagnostics.Statement_expected;
+                case ParsingContext.RestProperties: // fallthrough
                 case ParsingContext.TypeMembers: return Diagnostics.Property_or_signature_expected;
                 case ParsingContext.ClassMembers: return Diagnostics.Unexpected_token_A_constructor_method_accessor_or_property_was_expected;
                 case ParsingContext.EnumMembers: return Diagnostics.Enum_member_expected;
@@ -2399,6 +2432,36 @@ namespace ts {
             return members;
         }
 
+        function isStartOfMappedType() {
+            nextToken();
+            if (token() === SyntaxKind.ReadonlyKeyword) {
+                nextToken();
+            }
+            return token() === SyntaxKind.OpenBracketToken && nextTokenIsIdentifier() && nextToken() === SyntaxKind.InKeyword;
+        }
+
+        function parseMappedTypeParameter() {
+            const node = <TypeParameterDeclaration>createNode(SyntaxKind.TypeParameter);
+            node.name = parseIdentifier();
+            parseExpected(SyntaxKind.InKeyword);
+            node.constraint = parseType();
+            return finishNode(node);
+        }
+
+        function parseMappedType() {
+            const node = <MappedTypeNode>createNode(SyntaxKind.MappedType);
+            parseExpected(SyntaxKind.OpenBraceToken);
+            node.readonlyToken = parseOptionalToken(SyntaxKind.ReadonlyKeyword);
+            parseExpected(SyntaxKind.OpenBracketToken);
+            node.typeParameter = parseMappedTypeParameter();
+            parseExpected(SyntaxKind.CloseBracketToken);
+            node.questionToken = parseOptionalToken(SyntaxKind.QuestionToken);
+            node.type = parseTypeAnnotation();
+            parseSemicolon();
+            parseExpected(SyntaxKind.CloseBraceToken);
+            return finishNode(node);
+        }
+
         function parseTupleType(): TupleTypeNode {
             const node = <TupleTypeNode>createNode(SyntaxKind.TupleType);
             node.elementTypes = parseBracketedList(ParsingContext.TupleElementTypes, parseType, SyntaxKind.OpenBracketToken, SyntaxKind.CloseBracketToken);
@@ -2472,7 +2535,7 @@ namespace ts {
                 case SyntaxKind.TypeOfKeyword:
                     return parseTypeQuery();
                 case SyntaxKind.OpenBraceToken:
-                    return parseTypeLiteral();
+                    return lookAhead(isStartOfMappedType) ? parseMappedType() : parseTypeLiteral();
                 case SyntaxKind.OpenBracketToken:
                     return parseTupleType();
                 case SyntaxKind.OpenParenToken:
@@ -2498,6 +2561,8 @@ namespace ts {
                 case SyntaxKind.OpenBraceToken:
                 case SyntaxKind.OpenBracketToken:
                 case SyntaxKind.LessThanToken:
+                case SyntaxKind.BarToken:
+                case SyntaxKind.AmpersandToken:
                 case SyntaxKind.NewKeyword:
                 case SyntaxKind.StringLiteral:
                 case SyntaxKind.NumericLiteral:
@@ -2557,6 +2622,7 @@ namespace ts {
         }
 
         function parseUnionOrIntersectionType(kind: SyntaxKind, parseConstituentType: () => TypeNode, operator: SyntaxKind): TypeNode {
+            parseOptional(operator);
             let type = parseConstituentType();
             if (token() === operator) {
                 const types = createNodeArray<TypeNode>([type], type.pos);
@@ -3851,6 +3917,7 @@ namespace ts {
 
             parseExpected(SyntaxKind.OpenBraceToken);
             if (token() !== SyntaxKind.CloseBraceToken) {
+                node.dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
                 node.expression = parseAssignmentExpressionOrHigher();
             }
             if (inExpressionContext) {
@@ -4122,7 +4189,7 @@ namespace ts {
         }
 
         function parseSpreadElement(): Expression {
-            const node = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression);
+            const node = <SpreadElement>createNode(SyntaxKind.SpreadElement);
             parseExpected(SyntaxKind.DotDotDotToken);
             node.expression = parseAssignmentExpressionOrHigher();
             return finishNode(node);
@@ -4162,6 +4229,12 @@ namespace ts {
 
         function parseObjectLiteralElement(): ObjectLiteralElementLike {
             const fullStart = scanner.getStartPos();
+            const dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
+            if (dotDotDotToken) {
+                const spreadElement = <SpreadAssignment>createNode(SyntaxKind.SpreadAssignment, fullStart);
+                spreadElement.expression = parseAssignmentExpressionOrHigher();
+                return addJSDocComment(finishNode(spreadElement));
+            }
             const decorators = parseDecorators();
             const modifiers = parseModifiers();
 
@@ -4260,15 +4333,22 @@ namespace ts {
             return isIdentifier() ? parseIdentifier() : undefined;
         }
 
-        function parseNewExpression(): NewExpression {
-            const node = <NewExpression>createNode(SyntaxKind.NewExpression);
+        function parseNewExpression(): NewExpression | MetaProperty {
+            const fullStart = scanner.getStartPos();
             parseExpected(SyntaxKind.NewKeyword);
+            if (parseOptional(SyntaxKind.DotToken)) {
+                const node = <MetaProperty>createNode(SyntaxKind.MetaProperty, fullStart);
+                node.keywordToken = SyntaxKind.NewKeyword;
+                node.name = parseIdentifierName();
+                return finishNode(node);
+            }
+
+            const node = <NewExpression>createNode(SyntaxKind.NewExpression, fullStart);
             node.expression = parseMemberExpressionOrHigher();
             node.typeArguments = tryParse(parseTypeArgumentsInExpression);
             if (node.typeArguments || token() === SyntaxKind.OpenParenToken) {
                 node.arguments = parseArgumentList();
             }
-
             return finishNode(node);
         }
 
@@ -4865,6 +4945,7 @@ namespace ts {
 
         function parseObjectBindingElement(): BindingElement {
             const node = <BindingElement>createNode(SyntaxKind.BindingElement);
+            node.dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
             const tokenIsIdentifier = isIdentifier();
             const propertyName = parsePropertyName();
             if (tokenIsIdentifier && token() !== SyntaxKind.ColonToken) {
@@ -5449,7 +5530,7 @@ namespace ts {
                 node.flags |= NodeFlags.GlobalAugmentation;
             }
             else {
-                node.name = parseLiteralNode(/*internName*/ true);
+                node.name = <StringLiteral>parseLiteralNode(/*internName*/ true);
             }
 
             if (token() === SyntaxKind.OpenBraceToken) {
@@ -5809,6 +5890,7 @@ namespace ts {
             JsxChildren,               // Things between opening and closing JSX tags
             ArrayLiteralMembers,       // Members in array literal
             Parameters,                // Parameters in parameter list
+            RestProperties,            // Property names in a rest type list
             TypeParameters,            // Type parameters in type parameter list
             TypeArguments,             // Type arguments in type argument list
             TupleElementTypes,         // Element types in tuple element type list
@@ -6238,6 +6320,7 @@ namespace ts {
                     }
                     if (token() === SyntaxKind.NewLineTrivia) {
                         state = JSDocState.BeginningOfLine;
+                        indent = 0;
                         nextJSDocToken();
                     }
                     while (token() !== SyntaxKind.EndOfFileToken) {
@@ -6265,7 +6348,7 @@ namespace ts {
                                 break;
                             case SyntaxKind.AsteriskToken:
                                 const asterisk = scanner.getTokenText();
-                                if (state === JSDocState.SawAsterisk) {
+                                if (state === JSDocState.SawAsterisk || state === JSDocState.SavingComments) {
                                     // If we've already seen an asterisk, then we can no longer parse a tag on this line
                                     state = JSDocState.SavingComments;
                                     pushComment(asterisk);
@@ -6286,7 +6369,10 @@ namespace ts {
                             case SyntaxKind.WhitespaceTrivia:
                                 // only collect whitespace if we're already saving comments or have just crossed the comment indent margin
                                 const whitespace = scanner.getTokenText();
-                                if (state === JSDocState.SavingComments || margin !== undefined && indent + whitespace.length > margin) {
+                                if (state === JSDocState.SavingComments) {
+                                    comments.push(whitespace);
+                                }
+                                else if (margin !== undefined && indent + whitespace.length > margin) {
                                     comments.push(whitespace.slice(margin - indent - 1));
                                 }
                                 indent += whitespace.length;
@@ -6294,6 +6380,8 @@ namespace ts {
                             case SyntaxKind.EndOfFileToken:
                                 break;
                             default:
+                                // anything other than whitespace or asterisk at the beginning of the line starts the comment text
+                                state = JSDocState.SavingComments;
                                 pushComment(scanner.getTokenText());
                                 break;
                         }
@@ -6359,6 +6447,9 @@ namespace ts {
                     let tag: JSDocTag;
                     if (tagName) {
                         switch (tagName.text) {
+                            case "augments":
+                                tag = parseAugmentsTag(atToken, tagName);
+                                break;
                             case "param":
                                 tag = parseParamTag(atToken, tagName);
                                 break;
@@ -6575,6 +6666,16 @@ namespace ts {
                     return finishNode(result);
                 }
 
+                function parseAugmentsTag(atToken: AtToken, tagName: Identifier): JSDocAugmentsTag {
+                    const typeExpression = tryParseTypeExpression();
+
+                    const result = <JSDocAugmentsTag>createNode(SyntaxKind.JSDocAugmentsTag, atToken.pos);
+                    result.atToken = atToken;
+                    result.tagName = tagName;
+                    result.typeExpression = typeExpression;
+                    return finishNode(result);
+                }
+
                 function parseTypedefTag(atToken: AtToken, tagName: Identifier): JSDocTypedefTag {
                     const typeExpression = tryParseTypeExpression();
                     skipWhitespace();
@@ -6887,8 +6988,8 @@ namespace ts {
                 }
 
                 forEachChild(node, visitNode, visitArray);
-                if (node.jsDocComments) {
-                    for (const jsDocComment of node.jsDocComments) {
+                if (node.jsDoc) {
+                    for (const jsDocComment of node.jsDoc) {
                         forEachChild(jsDocComment, visitNode, visitArray);
                     }
                 }
@@ -7314,7 +7415,7 @@ namespace ts {
                     if (position >= array.pos && position < array.end) {
                         // position was in this array.  Search through this array to see if we find a
                         // viable element.
-                        for (let i = 0, n = array.length; i < n; i++) {
+                        for (let i = 0; i < array.length; i++) {
                             const child = array[i];
                             if (child) {
                                 if (child.pos === position) {

src/compiler/program.ts

@@ -3,10 +3,6 @@
 /// <reference path="core.ts" />
 
 namespace ts {
-    /** The version of the TypeScript compiler release */
-
-    export const version = "2.1.0";
-
     const emptyArray: any[] = [];
 
     export function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName = "tsconfig.json"): string {
@@ -44,7 +40,8 @@ namespace ts {
                 return;
             }
 
-            for (let i = 0, n = Math.min(commonPathComponents.length, sourcePathComponents.length); i < n; i++) {
+            const n = Math.min(commonPathComponents.length, sourcePathComponents.length);
+            for (let i = 0; i < n; i++) {
                 if (getCanonicalFileName(commonPathComponents[i]) !== getCanonicalFileName(sourcePathComponents[i])) {
                     if (i === 0) {
                         // Failed to find any common path component
@@ -329,6 +326,7 @@ namespace ts {
         // Map storing if there is emit blocking diagnostics for given input
         const hasEmitBlockingDiagnostics = createFileMap<boolean>(getCanonicalFileName);
 
+        let moduleResolutionCache: ModuleResolutionCache;
         let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModuleFull[];
         if (host.resolveModuleNames) {
             resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
@@ -342,7 +340,8 @@ namespace ts {
             });
         }
         else {
-            const loader = (moduleName: string, containingFile: string) => resolveModuleName(moduleName, containingFile, options, host).resolvedModule;
+            moduleResolutionCache = createModuleResolutionCache(currentDirectory, x => host.getCanonicalFileName(x));
+            const loader = (moduleName: string, containingFile: string) => resolveModuleName(moduleName, containingFile, options, host, moduleResolutionCache).resolvedModule;
             resolveModuleNamesWorker = (moduleNames, containingFile) => loadWithLocalCache(moduleNames, containingFile, loader);
         }
 
@@ -368,7 +367,8 @@ namespace ts {
 
             if (typeReferences.length) {
                 // This containingFilename needs to match with the one used in managed-side
-                const containingFilename = combinePaths(host.getCurrentDirectory(), "__inferred type names__.ts");
+                const containingDirectory = options.configFilePath ? getDirectoryPath(options.configFilePath) : host.getCurrentDirectory();
+                const containingFilename = combinePaths(containingDirectory, "__inferred type names__.ts");
                 const resolutions = resolveTypeReferenceDirectiveNamesWorker(typeReferences, containingFilename);
                 for (let i = 0; i < typeReferences.length; i++) {
                     processTypeReferenceDirective(typeReferences[i], resolutions[i]);
@@ -394,6 +394,9 @@ namespace ts {
             }
         }
 
+        // unconditionally set moduleResolutionCache to undefined to avoid unnecessary leaks
+        moduleResolutionCache = undefined;
+
         // unconditionally set oldProgram to undefined to prevent it from being captured in closure
         oldProgram = undefined;
 
@@ -431,13 +434,14 @@ namespace ts {
         return program;
 
         function getCommonSourceDirectory() {
-            if (typeof commonSourceDirectory === "undefined") {
-                if (options.rootDir && checkSourceFilesBelongToPath(files, options.rootDir)) {
+            if (commonSourceDirectory === undefined) {
+                const emittedFiles = filterSourceFilesInDirectory(files, isSourceFileFromExternalLibrary);
+                if (options.rootDir && checkSourceFilesBelongToPath(emittedFiles, options.rootDir)) {
                     // If a rootDir is specified and is valid use it as the commonSourceDirectory
                     commonSourceDirectory = getNormalizedAbsolutePath(options.rootDir, currentDirectory);
                 }
                 else {
-                    commonSourceDirectory = computeCommonSourceDirectory(files);
+                    commonSourceDirectory = computeCommonSourceDirectory(emittedFiles);
                 }
                 if (commonSourceDirectory && commonSourceDirectory[commonSourceDirectory.length - 1] !== directorySeparator) {
                     // Make sure directory path ends with directory separator so this string can directly
@@ -476,7 +480,7 @@ namespace ts {
                 return resolveModuleNamesWorker(moduleNames, containingFile);
             }
 
-            // at this point we know that either 
+            // at this point we know that either
             // - file has local declarations for ambient modules
             // OR
             // - old program state is available
@@ -670,7 +674,7 @@ namespace ts {
             }
 
             const modifiedFilePaths = modifiedSourceFiles.map(f => f.newFile.path);
-            // try to verify results of module resolution 
+            // try to verify results of module resolution
             for (const { oldFile: oldSourceFile, newFile: newSourceFile } of modifiedSourceFiles) {
                 const newSourceFilePath = getNormalizedAbsolutePath(newSourceFile.fileName, currentDirectory);
                 if (resolveModuleNamesWorker) {
@@ -697,7 +701,7 @@ namespace ts {
             }
 
             // update fileName -> file mapping
-            for (let i = 0, len = newSourceFiles.length; i < len; i++) {
+            for (let i = 0; i < newSourceFiles.length; i++) {
                 filesByName.set(filePaths[i], newSourceFiles[i]);
             }
 
@@ -908,48 +912,24 @@ namespace ts {
         function getJavaScriptSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
             return runWithCancellationToken(() => {
                 const diagnostics: Diagnostic[] = [];
+                let parent: Node = sourceFile;
                 walk(sourceFile);
 
                 return diagnostics;
 
-                function walk(node: Node): boolean {
-                    if (!node) {
-                        return false;
-                    }
+                function walk(node: Node) {
+                    // Return directly from the case if the given node doesnt want to visit each child
+                    // Otherwise break to visit each child
 
-                    switch (node.kind) {
-                        case SyntaxKind.ImportEqualsDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.import_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.ExportAssignment:
-                            if ((<ExportAssignment>node).isExportEquals) {
-                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.export_can_only_be_used_in_a_ts_file));
-                                return true;
+                    switch (parent.kind) {
+                        case SyntaxKind.Parameter:
+                        case SyntaxKind.PropertyDeclaration:
+                            if ((<ParameterDeclaration | PropertyDeclaration>parent).questionToken === node) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics._0_can_only_be_used_in_a_ts_file, "?"));
+                                return;
                             }
-                            break;
-                        case SyntaxKind.ClassDeclaration:
-                            let classDeclaration = <ClassDeclaration>node;
-                            if (checkModifiers(classDeclaration.modifiers) ||
-                                checkTypeParameters(classDeclaration.typeParameters)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.HeritageClause:
-                            let heritageClause = <HeritageClause>node;
-                            if (heritageClause.token === SyntaxKind.ImplementsKeyword) {
-                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.implements_clauses_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.InterfaceDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.interface_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.ModuleDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.module_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.TypeAliasDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.type_aliases_can_only_be_used_in_a_ts_file));
-                            return true;
+
+                        // Pass through
                         case SyntaxKind.MethodDeclaration:
                         case SyntaxKind.MethodSignature:
                         case SyntaxKind.Constructor:
@@ -959,124 +939,151 @@ namespace ts {
                         case SyntaxKind.FunctionDeclaration:
                         case SyntaxKind.ArrowFunction:
                         case SyntaxKind.FunctionDeclaration:
-                            const functionDeclaration = <FunctionLikeDeclaration>node;
-                            if (checkModifiers(functionDeclaration.modifiers) ||
-                                checkTypeParameters(functionDeclaration.typeParameters) ||
-                                checkTypeAnnotation(functionDeclaration.type)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.VariableStatement:
-                            const variableStatement = <VariableStatement>node;
-                            if (checkModifiers(variableStatement.modifiers)) {
-                                return true;
-                            }
-                            break;
                         case SyntaxKind.VariableDeclaration:
-                            const variableDeclaration = <VariableDeclaration>node;
-                            if (checkTypeAnnotation(variableDeclaration.type)) {
-                                return true;
+                            // type annotation
+                            if ((<FunctionLikeDeclaration | VariableDeclaration | ParameterDeclaration | PropertyDeclaration>parent).type === node) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.types_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                    }
+
+                    switch (node.kind) {
+                        case SyntaxKind.ImportEqualsDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.import_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.ExportAssignment:
+                            if ((<ExportAssignment>node).isExportEquals) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.export_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                            break;
+                        case SyntaxKind.HeritageClause:
+                            const heritageClause = <HeritageClause>node;
+                            if (heritageClause.token === SyntaxKind.ImplementsKeyword) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.implements_clauses_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                            break;
+                        case SyntaxKind.InterfaceDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.interface_declarations_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.ModuleDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.module_declarations_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.TypeAliasDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.type_aliases_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.EnumDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.enum_declarations_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.TypeAssertionExpression:
+                            const typeAssertionExpression = <TypeAssertion>node;
+                            diagnostics.push(createDiagnosticForNode(typeAssertionExpression.type, Diagnostics.type_assertion_expressions_can_only_be_used_in_a_ts_file));
+                            return;
+                    }
+
+                    const prevParent = parent;
+                    parent = node;
+                    forEachChild(node, walk, walkArray);
+                    parent = prevParent;
+                }
+
+                function walkArray(nodes: NodeArray<Node>) {
+                    if (parent.decorators === nodes && !options.experimentalDecorators) {
+                        diagnostics.push(createDiagnosticForNode(parent, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning));
+                    }
+
+                    switch (parent.kind) {
+                        case SyntaxKind.ClassDeclaration:
+                        case SyntaxKind.MethodDeclaration:
+                        case SyntaxKind.MethodSignature:
+                        case SyntaxKind.Constructor:
+                        case SyntaxKind.GetAccessor:
+                        case SyntaxKind.SetAccessor:
+                        case SyntaxKind.FunctionExpression:
+                        case SyntaxKind.FunctionDeclaration:
+                        case SyntaxKind.ArrowFunction:
+                        case SyntaxKind.FunctionDeclaration:
+                            // Check type parameters
+                            if (nodes === (<ClassDeclaration | FunctionLikeDeclaration>parent).typeParameters) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                            // pass through
+                        case SyntaxKind.VariableStatement:
+                            // Check modifiers
+                            if (nodes === (<ClassDeclaration | FunctionLikeDeclaration | VariableStatement>parent).modifiers) {
+                                return checkModifiers(<NodeArray<Modifier>>nodes, parent.kind === SyntaxKind.VariableStatement);
+                            }
+                            break;
+                        case SyntaxKind.PropertyDeclaration:
+                            // Check modifiers of property declaration
+                            if (nodes === (<PropertyDeclaration>parent).modifiers) {
+                                for (const modifier of <NodeArray<Modifier>>nodes) {
+                                    if (modifier.kind !== SyntaxKind.StaticKeyword) {
+                                        diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
+                                    }
+                                }
+                                return;
+                            }
+                            break;
+                        case SyntaxKind.Parameter:
+                            // Check modifiers of parameter declaration
+                            if (nodes === (<ParameterDeclaration>parent).modifiers) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.parameter_modifiers_can_only_be_used_in_a_ts_file));
+                                return;
                             }
                             break;
                         case SyntaxKind.CallExpression:
                         case SyntaxKind.NewExpression:
-                            const expression = <CallExpression>node;
-                            if (expression.typeArguments && expression.typeArguments.length > 0) {
-                                const start = expression.typeArguments.pos;
-                                diagnostics.push(createFileDiagnostic(sourceFile, start, expression.typeArguments.end - start,
-                                    Diagnostics.type_arguments_can_only_be_used_in_a_ts_file));
-                                return true;
+                        case SyntaxKind.ExpressionWithTypeArguments:
+                            // Check type arguments
+                            if (nodes === (<CallExpression | NewExpression | ExpressionWithTypeArguments>parent).typeArguments) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_arguments_can_only_be_used_in_a_ts_file));
+                                return;
                             }
                             break;
-                        case SyntaxKind.Parameter:
-                            const parameter = <ParameterDeclaration>node;
-                            if (parameter.modifiers) {
-                                const start = parameter.modifiers.pos;
-                                diagnostics.push(createFileDiagnostic(sourceFile, start, parameter.modifiers.end - start,
-                                    Diagnostics.parameter_modifiers_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            if (parameter.questionToken) {
-                                diagnostics.push(createDiagnosticForNode(parameter.questionToken, Diagnostics._0_can_only_be_used_in_a_ts_file, "?"));
-                                return true;
-                            }
-                            if (parameter.type) {
-                                diagnostics.push(createDiagnosticForNode(parameter.type, Diagnostics.types_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.PropertyDeclaration:
-                            const propertyDeclaration = <PropertyDeclaration>node;
-                            if (propertyDeclaration.modifiers) {
-                                for (const modifier of propertyDeclaration.modifiers) {
-                                    if (modifier.kind !== SyntaxKind.StaticKeyword) {
-                                        diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
-                                        return true;
-                                    }
+                    }
+
+                    for (const node of nodes) {
+                        walk(node);
+                    }
+                }
+
+                function checkModifiers(modifiers: NodeArray<Modifier>, isConstValid: boolean) {
+                    for (const modifier of modifiers) {
+                        switch (modifier.kind) {
+                            case SyntaxKind.ConstKeyword:
+                                if (isConstValid) {
+                                    continue;
                                 }
-                            }
-                            if (checkTypeAnnotation((<PropertyDeclaration>node).type)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.EnumDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.enum_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.TypeAssertionExpression:
-                            let typeAssertionExpression = <TypeAssertion>node;
-                            diagnostics.push(createDiagnosticForNode(typeAssertionExpression.type, Diagnostics.type_assertion_expressions_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.Decorator:
-                            if (!options.experimentalDecorators) {
-                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning));
-                            }
-                            return true;
-                    }
+                                // Fallthrough to report error
+                            case SyntaxKind.PublicKeyword:
+                            case SyntaxKind.PrivateKeyword:
+                            case SyntaxKind.ProtectedKeyword:
+                            case SyntaxKind.ReadonlyKeyword:
+                            case SyntaxKind.DeclareKeyword:
+                            case SyntaxKind.AbstractKeyword:
+                                diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
+                                break;
 
-                    return forEachChild(node, walk);
-                }
-
-                function checkTypeParameters(typeParameters: NodeArray<TypeParameterDeclaration>): boolean {
-                    if (typeParameters) {
-                        const start = typeParameters.pos;
-                        diagnostics.push(createFileDiagnostic(sourceFile, start, typeParameters.end - start, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
-                        return true;
-                    }
-                    return false;
-                }
-
-                function checkTypeAnnotation(type: TypeNode): boolean {
-                    if (type) {
-                        diagnostics.push(createDiagnosticForNode(type, Diagnostics.types_can_only_be_used_in_a_ts_file));
-                        return true;
-                    }
-
-                    return false;
-                }
-
-                function checkModifiers(modifiers: NodeArray<Modifier>): boolean {
-                    if (modifiers) {
-                        for (const modifier of modifiers) {
-                            switch (modifier.kind) {
-                                case SyntaxKind.PublicKeyword:
-                                case SyntaxKind.PrivateKeyword:
-                                case SyntaxKind.ProtectedKeyword:
-                                case SyntaxKind.ReadonlyKeyword:
-                                case SyntaxKind.DeclareKeyword:
-                                    diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
-                                    return true;
-
-                                // These are all legal modifiers.
-                                case SyntaxKind.StaticKeyword:
-                                case SyntaxKind.ExportKeyword:
-                                case SyntaxKind.ConstKeyword:
-                                case SyntaxKind.DefaultKeyword:
-                                case SyntaxKind.AbstractKeyword:
-                            }
+                            // These are all legal modifiers.
+                            case SyntaxKind.StaticKeyword:
+                            case SyntaxKind.ExportKeyword:
+                            case SyntaxKind.DefaultKeyword:
                         }
                     }
+                }
 
-                    return false;
+                function createDiagnosticForNodeArray(nodes: NodeArray<Node>, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
+                    const start = nodes.pos;
+                    return createFileDiagnostic(sourceFile, start, nodes.end - start, message, arg0, arg1, arg2);
+                }
+
+                // Since these are syntactic diagnostics, parent might not have been set
+                // this means the sourceFile cannot be infered from the node
+                function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
+                    return createDiagnosticForNodeInSourceFile(sourceFile, node, message, arg0, arg1, arg2);
                 }
             });
         }
@@ -1140,9 +1147,14 @@ namespace ts {
             if (options.importHelpers
                 && (options.isolatedModules || isExternalModuleFile)
                 && !file.isDeclarationFile) {
-                const externalHelpersModuleReference = <StringLiteral>createNode(SyntaxKind.StringLiteral);
+                // synthesize 'import "tslib"' declaration
+                const externalHelpersModuleReference = <StringLiteral>createSynthesizedNode(SyntaxKind.StringLiteral);
                 externalHelpersModuleReference.text = externalHelpersModuleNameText;
-                externalHelpersModuleReference.parent = file;
+                const importDecl = createSynthesizedNode(SyntaxKind.ImportDeclaration);
+
+                importDecl.parent = file;
+                externalHelpersModuleReference.parent = importDecl;
+
                 imports = [externalHelpersModuleReference];
             }
 
@@ -1164,7 +1176,7 @@ namespace ts {
                     case SyntaxKind.ImportDeclaration:
                     case SyntaxKind.ImportEqualsDeclaration:
                     case SyntaxKind.ExportDeclaration:
-                        let moduleNameExpr = getExternalModuleName(node);
+                        const moduleNameExpr = getExternalModuleName(node);
                         if (!moduleNameExpr || moduleNameExpr.kind !== SyntaxKind.StringLiteral) {
                             break;
                         }
@@ -1395,14 +1407,17 @@ namespace ts {
                     // If we already resolved to this file, it must have been a secondary reference. Check file contents
                     // for sameness and possibly issue an error
                     if (previousResolution) {
-                        const otherFileText = host.readFile(resolvedTypeReferenceDirective.resolvedFileName);
-                        if (otherFileText !== getSourceFile(previousResolution.resolvedFileName).text) {
-                            fileProcessingDiagnostics.add(createDiagnostic(refFile, refPos, refEnd,
-                                Diagnostics.Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict,
-                                typeReferenceDirective,
-                                resolvedTypeReferenceDirective.resolvedFileName,
-                                previousResolution.resolvedFileName
-                            ));
+                        // Don't bother reading the file again if it's the same file.
+                        if (resolvedTypeReferenceDirective.resolvedFileName !== previousResolution.resolvedFileName) {
+                            const otherFileText = host.readFile(resolvedTypeReferenceDirective.resolvedFileName);
+                            if (otherFileText !== getSourceFile(previousResolution.resolvedFileName).text) {
+                                fileProcessingDiagnostics.add(createDiagnostic(refFile, refPos, refEnd,
+                                    Diagnostics.Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict,
+                                    typeReferenceDirective,
+                                    resolvedTypeReferenceDirective.resolvedFileName,
+                                    previousResolution.resolvedFileName
+                                ));
+                            }
                         }
                         // don't overwrite previous resolution result
                         saveResolution = false;
@@ -1439,7 +1454,9 @@ namespace ts {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
                 file.resolvedModules = createMap<ResolvedModuleFull>();
-                const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
+                // Because global augmentation doesn't have string literal name, we can check for global augmentation as such.
+                const nonGlobalAugmentation = filter(file.moduleAugmentations, (moduleAugmentation) => moduleAugmentation.kind === SyntaxKind.StringLiteral);
+                const moduleNames = map(concatenate(file.imports, nonGlobalAugmentation), getTextOfLiteral);
                 const resolutions = resolveModuleNamesReusingOldState(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory), file);
                 Debug.assert(resolutions.length === moduleNames.length);
                 for (let i = 0; i < moduleNames.length; i++) {
@@ -1670,7 +1687,15 @@ namespace ts {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1, "emitDecoratorMetadata", "experimentalDecorators"));
             }
 
-            if (options.reactNamespace && !isIdentifierText(options.reactNamespace, languageVersion)) {
+            if (options.jsxFactory) {
+                if (options.reactNamespace) {
+                    programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_with_option_1, "reactNamespace", "jsxFactory"));
+                }
+                if (!parseIsolatedEntityName(options.jsxFactory, languageVersion)) {
+                    programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_jsxFactory_0_is_not_a_valid_identifier_or_qualified_name, options.jsxFactory));
+                }
+            }
+            else if (options.reactNamespace && !isIdentifierText(options.reactNamespace, languageVersion)) {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_reactNamespace_0_is_not_a_valid_identifier, options.reactNamespace));
             }
 
@@ -1690,18 +1715,13 @@ namespace ts {
                     const emitFilePath = toPath(emitFileName, currentDirectory, getCanonicalFileName);
                     // Report error if the output overwrites input file
                     if (filesByName.contains(emitFilePath)) {
-                        if (options.noEmitOverwritenFiles && !options.out && !options.outDir && !options.outFile) {
-                            blockEmittingOfFile(emitFileName);
-                        }
-                        else {
-                            let chain: DiagnosticMessageChain;
-                            if (!options.configFilePath) {
-                                // The program is from either an inferred project or an external project
-                                chain = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Adding_a_tsconfig_json_file_will_help_organize_projects_that_contain_both_TypeScript_and_JavaScript_files_Learn_more_at_https_Colon_Slash_Slashaka_ms_Slashtsconfig);
-                            }
-                            chain = chainDiagnosticMessages(chain, Diagnostics.Cannot_write_file_0_because_it_would_overwrite_input_file, emitFileName);
-                            blockEmittingOfFile(emitFileName, createCompilerDiagnosticFromMessageChain(chain));
+                        let chain: DiagnosticMessageChain;
+                        if (!options.configFilePath) {
+                            // The program is from either an inferred project or an external project
+                            chain = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Adding_a_tsconfig_json_file_will_help_organize_projects_that_contain_both_TypeScript_and_JavaScript_files_Learn_more_at_https_Colon_Slash_Slashaka_ms_Slashtsconfig);
                         }
+                        chain = chainDiagnosticMessages(chain, Diagnostics.Cannot_write_file_0_because_it_would_overwrite_input_file, emitFileName);
+                        blockEmittingOfFile(emitFileName, createCompilerDiagnosticFromMessageChain(chain));
                     }
 
                     // Report error if multiple files write into same file
@@ -1716,11 +1736,9 @@ namespace ts {
             }
         }
 
-        function blockEmittingOfFile(emitFileName: string, diag?: Diagnostic) {
+        function blockEmittingOfFile(emitFileName: string, diag: Diagnostic) {
             hasEmitBlockingDiagnostics.set(toPath(emitFileName, currentDirectory, getCanonicalFileName), true);
-            if (diag) {
-                programDiagnostics.add(diag);
-            }
+            programDiagnostics.add(diag);
         }
     }
 

src/compiler/scanner.ts

@@ -531,7 +531,7 @@ namespace ts {
             const ch = text.charCodeAt(pos);
 
             if ((pos + mergeConflictMarkerLength) < text.length) {
-                for (let i = 0, n = mergeConflictMarkerLength; i < n; i++) {
+                for (let i = 0; i < mergeConflictMarkerLength; i++) {
                     if (text.charCodeAt(pos + i) !== ch) {
                         return false;
                     }
@@ -643,7 +643,7 @@ namespace ts {
                     pos++;
                     continue;
                 case CharacterCodes.slash:
-                    let nextChar = text.charCodeAt(pos + 1);
+                    const nextChar = text.charCodeAt(pos + 1);
                     let hasTrailingNewLine = false;
                     if (nextChar === CharacterCodes.slash || nextChar === CharacterCodes.asterisk) {
                         const kind = nextChar === CharacterCodes.slash ? SyntaxKind.SingleLineCommentTrivia : SyntaxKind.MultiLineCommentTrivia;
@@ -766,7 +766,7 @@ namespace ts {
             return false;
         }
 
-        for (let i = 1, n = name.length; i < n; i++) {
+        for (let i = 1; i < name.length; i++) {
             if (!isIdentifierPart(name.charCodeAt(i), languageVersion)) {
                 return false;
             }
@@ -1563,7 +1563,7 @@ namespace ts {
                         pos++;
                         return token = SyntaxKind.AtToken;
                     case CharacterCodes.backslash:
-                        let cookedChar = peekUnicodeEscape();
+                        const cookedChar = peekUnicodeEscape();
                         if (cookedChar >= 0 && isIdentifierStart(cookedChar, languageVersion)) {
                             pos += 6;
                             tokenValue = String.fromCharCode(cookedChar) + scanIdentifierParts();

src/compiler/sourcemap.ts

@@ -427,7 +427,7 @@ namespace ts {
 
             encodeLastRecordedSourceMapSpan();
 
-            return stringify({
+            return JSON.stringify({
                 version: 3,
                 file: sourceMapData.sourceMapFile,
                 sourceRoot: sourceMapData.sourceMapSourceRoot,

src/compiler/sys.ts

@@ -160,7 +160,7 @@ namespace ts {
 
             function getNames(collection: any): string[] {
                 const result: string[] = [];
-                for (let e = new Enumerator(collection); !e.atEnd(); e.moveNext()) {
+                for (const e = new Enumerator(collection); !e.atEnd(); e.moveNext()) {
                     result.push(e.item().Name);
                 }
                 return result.sort();

src/compiler/transformer.ts

@@ -1,6 +1,7 @@
 /// <reference path="visitor.ts" />
 /// <reference path="transformers/ts.ts" />
 /// <reference path="transformers/jsx.ts" />
+/// <reference path="transformers/esnext.ts" />
 /// <reference path="transformers/es2017.ts" />
 /// <reference path="transformers/es2016.ts" />
 /// <reference path="transformers/es2015.ts" />
@@ -26,84 +27,6 @@ namespace ts {
         EmitNotifications = 1 << 1,
     }
 
-    export interface TransformationResult {
-        /**
-         * Gets the transformed source files.
-         */
-        transformed: SourceFile[];
-
-        /**
-         * Emits the substitute for a node, if one is available; otherwise, emits the node.
-         *
-         * @param emitContext The current emit context.
-         * @param node The node to substitute.
-         * @param emitCallback A callback used to emit the node or its substitute.
-         */
-        emitNodeWithSubstitution(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void;
-
-        /**
-         * Emits a node with possible notification.
-         *
-         * @param emitContext The current emit context.
-         * @param node The node to emit.
-         * @param emitCallback A callback used to emit the node.
-         */
-        emitNodeWithNotification(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void;
-    }
-
-    export interface TransformationContext extends LexicalEnvironment {
-        getCompilerOptions(): CompilerOptions;
-        getEmitResolver(): EmitResolver;
-        getEmitHost(): EmitHost;
-
-        /**
-         * Hoists a function declaration to the containing scope.
-         */
-        hoistFunctionDeclaration(node: FunctionDeclaration): void;
-
-        /**
-         * Hoists a variable declaration to the containing scope.
-         */
-        hoistVariableDeclaration(node: Identifier): void;
-
-        /**
-         * Enables expression substitutions in the pretty printer for the provided SyntaxKind.
-         */
-        enableSubstitution(kind: SyntaxKind): void;
-
-        /**
-         * Determines whether expression substitutions are enabled for the provided node.
-         */
-        isSubstitutionEnabled(node: Node): boolean;
-
-        /**
-         * Hook used by transformers to substitute expressions just before they
-         * are emitted by the pretty printer.
-         */
-        onSubstituteNode?: (emitContext: EmitContext, node: Node) => Node;
-
-        /**
-         * Enables before/after emit notifications in the pretty printer for the provided
-         * SyntaxKind.
-         */
-        enableEmitNotification(kind: SyntaxKind): void;
-
-        /**
-         * Determines whether before/after emit notifications should be raised in the pretty
-         * printer when it emits a node.
-         */
-        isEmitNotificationEnabled(node: Node): boolean;
-
-        /**
-         * Hook used to allow transformers to capture state before or after
-         * the printer emits a node.
-         */
-        onEmitNode?: (emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void) => void;
-    }
-
-    /* @internal */
-    export type Transformer = (context: TransformationContext) => (node: SourceFile) => SourceFile;
-
     export function getTransformers(compilerOptions: CompilerOptions) {
         const jsx = compilerOptions.jsx;
         const languageVersion = getEmitScriptTarget(compilerOptions);
@@ -116,6 +39,10 @@ namespace ts {
             transformers.push(transformJsx);
         }
 
+        if (languageVersion < ScriptTarget.ESNext) {
+            transformers.push(transformESNext);
+        }
+
         if (languageVersion < ScriptTarget.ES2017) {
             transformers.push(transformES2017);
         }
@@ -149,14 +76,18 @@ namespace ts {
      * @param transforms An array of Transformers.
      */
     export function transformFiles(resolver: EmitResolver, host: EmitHost, sourceFiles: SourceFile[], transformers: Transformer[]): TransformationResult {
-        const lexicalEnvironmentVariableDeclarationsStack: VariableDeclaration[][] = [];
-        const lexicalEnvironmentFunctionDeclarationsStack: FunctionDeclaration[][] = [];
         const enabledSyntaxKindFeatures = new Array<SyntaxKindFeatureFlags>(SyntaxKind.Count);
 
+        let lexicalEnvironmentDisabled = false;
+
+        let lexicalEnvironmentVariableDeclarations: VariableDeclaration[];
+        let lexicalEnvironmentFunctionDeclarations: FunctionDeclaration[];
+        let lexicalEnvironmentVariableDeclarationsStack: VariableDeclaration[][] = [];
+        let lexicalEnvironmentFunctionDeclarationsStack: FunctionDeclaration[][] = [];
         let lexicalEnvironmentStackOffset = 0;
-        let hoistedVariableDeclarations: VariableDeclaration[];
-        let hoistedFunctionDeclarations: FunctionDeclaration[];
-        let lexicalEnvironmentDisabled: boolean;
+        let lexicalEnvironmentSuspended = false;
+
+        let emitHelpers: EmitHelper[];
 
         // The transformation context is provided to each transformer as part of transformer
         // initialization.
@@ -164,10 +95,14 @@ namespace ts {
             getCompilerOptions: () => host.getCompilerOptions(),
             getEmitResolver: () => resolver,
             getEmitHost: () => host,
+            startLexicalEnvironment,
+            suspendLexicalEnvironment,
+            resumeLexicalEnvironment,
+            endLexicalEnvironment,
             hoistVariableDeclaration,
             hoistFunctionDeclaration,
-            startLexicalEnvironment,
-            endLexicalEnvironment,
+            requestEmitHelper,
+            readEmitHelpers,
             onSubstituteNode: (_emitContext, node) => node,
             enableSubstitution,
             isSubstitutionEnabled,
@@ -280,11 +215,11 @@ namespace ts {
         function hoistVariableDeclaration(name: Identifier): void {
             Debug.assert(!lexicalEnvironmentDisabled, "Cannot modify the lexical environment during the print phase.");
             const decl = createVariableDeclaration(name);
-            if (!hoistedVariableDeclarations) {
-                hoistedVariableDeclarations = [decl];
+            if (!lexicalEnvironmentVariableDeclarations) {
+                lexicalEnvironmentVariableDeclarations = [decl];
             }
             else {
-                hoistedVariableDeclarations.push(decl);
+                lexicalEnvironmentVariableDeclarations.push(decl);
             }
         }
 
@@ -293,11 +228,11 @@ namespace ts {
          */
         function hoistFunctionDeclaration(func: FunctionDeclaration): void {
             Debug.assert(!lexicalEnvironmentDisabled, "Cannot modify the lexical environment during the print phase.");
-            if (!hoistedFunctionDeclarations) {
-                hoistedFunctionDeclarations = [func];
+            if (!lexicalEnvironmentFunctionDeclarations) {
+                lexicalEnvironmentFunctionDeclarations = [func];
             }
             else {
-                hoistedFunctionDeclarations.push(func);
+                lexicalEnvironmentFunctionDeclarations.push(func);
             }
         }
 
@@ -307,16 +242,31 @@ namespace ts {
          */
         function startLexicalEnvironment(): void {
             Debug.assert(!lexicalEnvironmentDisabled, "Cannot start a lexical environment during the print phase.");
+            Debug.assert(!lexicalEnvironmentSuspended, "Lexical environment is suspended.");
 
             // Save the current lexical environment. Rather than resizing the array we adjust the
             // stack size variable. This allows us to reuse existing array slots we've
             // already allocated between transformations to avoid allocation and GC overhead during
             // transformation.
-            lexicalEnvironmentVariableDeclarationsStack[lexicalEnvironmentStackOffset] = hoistedVariableDeclarations;
-            lexicalEnvironmentFunctionDeclarationsStack[lexicalEnvironmentStackOffset] = hoistedFunctionDeclarations;
+            lexicalEnvironmentVariableDeclarationsStack[lexicalEnvironmentStackOffset] = lexicalEnvironmentVariableDeclarations;
+            lexicalEnvironmentFunctionDeclarationsStack[lexicalEnvironmentStackOffset] = lexicalEnvironmentFunctionDeclarations;
             lexicalEnvironmentStackOffset++;
-            hoistedVariableDeclarations = undefined;
-            hoistedFunctionDeclarations = undefined;
+            lexicalEnvironmentVariableDeclarations = undefined;
+            lexicalEnvironmentFunctionDeclarations = undefined;
+        }
+
+        /** Suspends the current lexical environment, usually after visiting a parameter list. */
+        function suspendLexicalEnvironment(): void {
+            Debug.assert(!lexicalEnvironmentDisabled, "Cannot suspend a lexical environment during the print phase.");
+            Debug.assert(!lexicalEnvironmentSuspended, "Lexical environment is already suspended.");
+            lexicalEnvironmentSuspended = true;
+        }
+
+        /** Resumes a suspended lexical environment, usually before visiting a function body. */
+        function resumeLexicalEnvironment(): void {
+            Debug.assert(!lexicalEnvironmentDisabled, "Cannot resume a lexical environment during the print phase.");
+            Debug.assert(lexicalEnvironmentSuspended, "Lexical environment is not suspended.");
+            lexicalEnvironmentSuspended = false;
         }
 
         /**
@@ -325,17 +275,18 @@ namespace ts {
          */
         function endLexicalEnvironment(): Statement[] {
             Debug.assert(!lexicalEnvironmentDisabled, "Cannot end a lexical environment during the print phase.");
+            Debug.assert(!lexicalEnvironmentSuspended, "Lexical environment is suspended.");
 
             let statements: Statement[];
-            if (hoistedVariableDeclarations || hoistedFunctionDeclarations) {
-                if (hoistedFunctionDeclarations) {
-                    statements = [...hoistedFunctionDeclarations];
+            if (lexicalEnvironmentVariableDeclarations || lexicalEnvironmentFunctionDeclarations) {
+                if (lexicalEnvironmentFunctionDeclarations) {
+                    statements = [...lexicalEnvironmentFunctionDeclarations];
                 }
 
-                if (hoistedVariableDeclarations) {
+                if (lexicalEnvironmentVariableDeclarations) {
                     const statement = createVariableStatement(
                         /*modifiers*/ undefined,
-                        createVariableDeclarationList(hoistedVariableDeclarations)
+                        createVariableDeclarationList(lexicalEnvironmentVariableDeclarations)
                     );
 
                     if (!statements) {
@@ -349,9 +300,26 @@ namespace ts {
 
             // Restore the previous lexical environment.
             lexicalEnvironmentStackOffset--;
-            hoistedVariableDeclarations = lexicalEnvironmentVariableDeclarationsStack[lexicalEnvironmentStackOffset];
-            hoistedFunctionDeclarations = lexicalEnvironmentFunctionDeclarationsStack[lexicalEnvironmentStackOffset];
+            lexicalEnvironmentVariableDeclarations = lexicalEnvironmentVariableDeclarationsStack[lexicalEnvironmentStackOffset];
+            lexicalEnvironmentFunctionDeclarations = lexicalEnvironmentFunctionDeclarationsStack[lexicalEnvironmentStackOffset];
+            if (lexicalEnvironmentStackOffset === 0) {
+                lexicalEnvironmentVariableDeclarationsStack = [];
+                lexicalEnvironmentFunctionDeclarationsStack = [];
+            }
             return statements;
         }
+
+        function requestEmitHelper(helper: EmitHelper): void {
+            Debug.assert(!lexicalEnvironmentDisabled, "Cannot modify the lexical environment during the print phase.");
+            Debug.assert(!helper.scoped, "Cannot request a scoped emit helper.");
+            emitHelpers = append(emitHelpers, helper);
+        }
+
+        function readEmitHelpers(): EmitHelper[] | undefined {
+            Debug.assert(!lexicalEnvironmentDisabled, "Cannot modify the lexical environment during the print phase.");
+            const helpers = emitHelpers;
+            emitHelpers = undefined;
+            return helpers;
+        }
     }
 }

src/compiler/transformers/destructuring.ts

@@ -3,410 +3,397 @@
 
 /*@internal*/
 namespace ts {
+    interface FlattenContext {
+        context: TransformationContext;
+        level: FlattenLevel;
+        hoistTempVariables: boolean;
+        emitExpression: (value: Expression) => void;
+        emitBindingOrAssignment: (target: BindingOrAssignmentElementTarget, value: Expression, location: TextRange, original: Node) => void;
+        createArrayBindingOrAssignmentPattern: (elements: BindingOrAssignmentElement[]) => ArrayBindingOrAssignmentPattern;
+        createObjectBindingOrAssignmentPattern: (elements: BindingOrAssignmentElement[]) => ObjectBindingOrAssignmentPattern;
+        createArrayBindingOrAssignmentElement: (node: Identifier) => BindingOrAssignmentElement;
+        visitor?: (node: Node) => VisitResult<Node>;
+    }
+
+    export const enum FlattenLevel {
+        All,
+        ObjectRest,
+    }
+
     /**
-     * Flattens a destructuring assignment expression.
+     * Flattens a DestructuringAssignment or a VariableDeclaration to an expression.
      *
-     * @param root The destructuring assignment expression.
-     * @param needsValue Indicates whether the value from the right-hand-side of the
-     *                   destructuring assignment is needed as part of a larger expression.
-     * @param recordTempVariable A callback used to record new temporary variables.
-     * @param visitor An optional visitor to use to visit expressions.
+     * @param node The node to flatten.
+     * @param visitor An optional visitor used to visit initializers.
+     * @param context The transformation context.
+     * @param level Indicates the extent to which flattening should occur.
+     * @param needsValue An optional value indicating whether the value from the right-hand-side of
+     * the destructuring assignment is needed as part of a larger expression.
+     * @param createAssignmentCallback An optional callback used to create the assignment expression.
      */
     export function flattenDestructuringAssignment(
+        node: VariableDeclaration | DestructuringAssignment,
+        visitor: ((node: Node) => VisitResult<Node>) | undefined,
         context: TransformationContext,
-        node: BinaryExpression,
-        needsValue: boolean,
-        recordTempVariable: (node: Identifier) => void,
-        visitor?: (node: Node) => VisitResult<Node>): Expression {
-
-        if (isEmptyObjectLiteralOrArrayLiteral(node.left)) {
-            const right = node.right;
-            if (isDestructuringAssignment(right)) {
-                return flattenDestructuringAssignment(context, right, needsValue, recordTempVariable, visitor);
-            }
-            else {
-                return node.right;
-            }
-        }
-
+        level: FlattenLevel,
+        needsValue?: boolean,
+        createAssignmentCallback?: (name: Identifier, value: Expression, location?: TextRange) => Expression): Expression {
         let location: TextRange = node;
-        let value = node.right;
-        const expressions: Expression[] = [];
-        if (needsValue) {
-            // If the right-hand value of the destructuring assignment needs to be preserved (as
-            // is the case when the destructuring assignmen) is part of a larger expression),
-            // then we need to cache the right-hand value.
-            //
-            // The source map location for the assignment should point to the entire binary
-            // expression.
-            value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment, visitor);
-        }
-        else if (nodeIsSynthesized(node)) {
-            // Generally, the source map location for a destructuring assignment is the root
-            // expression.
-            //
-            // However, if the root expression is synthesized (as in the case
-            // of the initializer when transforming a ForOfStatement), then the source map
-            // location should point to the right-hand value of the expression.
-            location = value;
+        let value: Expression;
+        if (isDestructuringAssignment(node)) {
+            value = node.right;
+            while (isEmptyObjectLiteralOrArrayLiteral(node.left)) {
+                if (isDestructuringAssignment(value)) {
+                    location = node = value;
+                    value = node.right;
+                }
+                else {
+                    return value;
+                }
+            }
         }
 
-        flattenDestructuring(node, value, location, emitAssignment, emitTempVariableAssignment, visitor);
+        let expressions: Expression[];
+        const flattenContext: FlattenContext = {
+            context,
+            level,
+            hoistTempVariables: true,
+            emitExpression,
+            emitBindingOrAssignment,
+            createArrayBindingOrAssignmentPattern: makeArrayAssignmentPattern,
+            createObjectBindingOrAssignmentPattern: makeObjectAssignmentPattern,
+            createArrayBindingOrAssignmentElement: makeAssignmentElement,
+            visitor
+        };
+
+        if (value) {
+            value = visitNode(value, visitor, isExpression);
+            if (needsValue) {
+                // If the right-hand value of the destructuring assignment needs to be preserved (as
+                // is the case when the destructuring assignment is part of a larger expression),
+                // then we need to cache the right-hand value.
+                //
+                // The source map location for the assignment should point to the entire binary
+                // expression.
+                value = ensureIdentifier(flattenContext, value, /*reuseIdentifierExpressions*/ true, location);
+            }
+            else if (nodeIsSynthesized(node)) {
+                // Generally, the source map location for a destructuring assignment is the root
+                // expression.
+                //
+                // However, if the root expression is synthesized (as in the case
+                // of the initializer when transforming a ForOfStatement), then the source map
+                // location should point to the right-hand value of the expression.
+                location = value;
+            }
+        }
+
+        flattenBindingOrAssignmentElement(flattenContext, node, value, location, /*skipInitializer*/ isDestructuringAssignment(node));
+
+        if (value && needsValue) {
+            if (!some(expressions)) {
+                return value;
+            }
 
-        if (needsValue) {
             expressions.push(value);
         }
 
-        const expression = inlineExpressions(expressions);
-        aggregateTransformFlags(expression);
-        return expression;
-
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange) {
-            const expression = createAssignment(name, value, location);
+        return aggregateTransformFlags(inlineExpressions(expressions)) || createOmittedExpression();
 
+        function emitExpression(expression: Expression) {
             // NOTE: this completely disables source maps, but aligns with the behavior of
             //       `emitAssignment` in the old emitter.
             setEmitFlags(expression, EmitFlags.NoNestedSourceMaps);
-
             aggregateTransformFlags(expression);
-            expressions.push(expression);
+            expressions = append(expressions, expression);
         }
 
-        function emitTempVariableAssignment(value: Expression, location: TextRange) {
-            const name = createTempVariable(recordTempVariable);
-            emitAssignment(name, value, location);
-            return name;
-        }
-    }
-
-    /**
-     * Flattens binding patterns in a parameter declaration.
-     *
-     * @param node The ParameterDeclaration to flatten.
-     * @param value The rhs value for the binding pattern.
-     * @param visitor An optional visitor to use to visit expressions.
-     */
-    export function flattenParameterDestructuring(
-        node: ParameterDeclaration,
-        value: Expression,
-        visitor?: (node: Node) => VisitResult<Node>) {
-        const declarations: VariableDeclaration[] = [];
-
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, visitor);
-
-        return declarations;
-
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange) {
-            const declaration = createVariableDeclaration(name, /*type*/ undefined, value, location);
-
-            // NOTE: this completely disables source maps, but aligns with the behavior of
-            //       `emitAssignment` in the old emitter.
-            setEmitFlags(declaration, EmitFlags.NoNestedSourceMaps);
-
-            aggregateTransformFlags(declaration);
-            declarations.push(declaration);
-        }
-
-        function emitTempVariableAssignment(value: Expression, location: TextRange) {
-            const name = createTempVariable(/*recordTempVariable*/ undefined);
-            emitAssignment(name, value, location);
-            return name;
-        }
-    }
-
-    /**
-     * Flattens binding patterns in a variable declaration.
-     *
-     * @param node The VariableDeclaration to flatten.
-     * @param value An optional rhs value for the binding pattern.
-     * @param visitor An optional visitor to use to visit expressions.
-     */
-    export function flattenVariableDestructuring(
-        node: VariableDeclaration,
-        value?: Expression,
-        visitor?: (node: Node) => VisitResult<Node>,
-        recordTempVariable?: (node: Identifier) => void) {
-        const declarations: VariableDeclaration[] = [];
-
-        let pendingAssignments: Expression[];
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, visitor);
-
-        return declarations;
-
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange, original: Node) {
-            if (pendingAssignments) {
-                pendingAssignments.push(value);
-                value = inlineExpressions(pendingAssignments);
-                pendingAssignments = undefined;
-            }
-
-            const declaration = createVariableDeclaration(name, /*type*/ undefined, value, location);
-            declaration.original = original;
-
-            // NOTE: this completely disables source maps, but aligns with the behavior of
-            //       `emitAssignment` in the old emitter.
-            setEmitFlags(declaration, EmitFlags.NoNestedSourceMaps);
-
-            declarations.push(declaration);
-            aggregateTransformFlags(declaration);
-        }
-
-        function emitTempVariableAssignment(value: Expression, location: TextRange) {
-            const name = createTempVariable(recordTempVariable);
-            if (recordTempVariable) {
-                const assignment = createAssignment(name, value, location);
-                if (pendingAssignments) {
-                    pendingAssignments.push(assignment);
-                }
-                else {
-                    pendingAssignments = [assignment];
-                }
-            }
-            else {
-                emitAssignment(name, value, location, /*original*/ undefined);
-            }
-            return name;
-        }
-    }
-
-    /**
-     * Flattens binding patterns in a variable declaration and transforms them into an expression.
-     *
-     * @param node The VariableDeclaration to flatten.
-     * @param recordTempVariable A callback used to record new temporary variables.
-     * @param createAssignmentCallback An optional callback used to create assignment expressions
-     * for non-temporary variables.
-     * @param visitor An optional visitor to use to visit expressions.
-     */
-    export function flattenVariableDestructuringToExpression(
-        node: VariableDeclaration,
-        recordTempVariable: (name: Identifier) => void,
-        createAssignmentCallback?: (name: Identifier, value: Expression, location?: TextRange) => Expression,
-        visitor?: (node: Node) => VisitResult<Node>) {
-
-        const pendingAssignments: Expression[] = [];
-
-        flattenDestructuring(node, /*value*/ undefined, node, emitAssignment, emitTempVariableAssignment, visitor);
-
-        const expression = inlineExpressions(pendingAssignments);
-        aggregateTransformFlags(expression);
-        return expression;
-
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange, original: Node) {
+        function emitBindingOrAssignment(target: BindingOrAssignmentElementTarget, value: Expression, location: TextRange, original: Node) {
+            Debug.assertNode(target, createAssignmentCallback ? isIdentifier : isExpression);
             const expression = createAssignmentCallback
-                ? createAssignmentCallback(name, value, location)
-                : createAssignment(name, value, location);
-
-            emitPendingAssignment(expression, original);
-        }
-
-        function emitTempVariableAssignment(value: Expression, location: TextRange) {
-            const name = createTempVariable(recordTempVariable);
-            emitPendingAssignment(createAssignment(name, value, location), /*original*/ undefined);
-            return name;
-        }
-
-        function emitPendingAssignment(expression: Expression, original: Node) {
+                ? createAssignmentCallback(<Identifier>target, value, location)
+                : createAssignment(visitNode(<Expression>target, visitor, isExpression), value, location);
             expression.original = original;
-
-            // NOTE: this completely disables source maps, but aligns with the behavior of
-            //       `emitAssignment` in the old emitter.
-            setEmitFlags(expression, EmitFlags.NoNestedSourceMaps);
-
-            pendingAssignments.push(expression);
+            emitExpression(expression);
         }
     }
 
-    function flattenDestructuring(
-        root: VariableDeclaration | ParameterDeclaration | BindingElement | BinaryExpression,
-        value: Expression,
+    /**
+     * Flattens a VariableDeclaration or ParameterDeclaration to one or more variable declarations.
+     *
+     * @param node The node to flatten.
+     * @param visitor An optional visitor used to visit initializers.
+     * @param context The transformation context.
+     * @param boundValue The value bound to the declaration.
+     * @param skipInitializer A value indicating whether to ignore the initializer of `node`.
+     * @param hoistTempVariables Indicates whether temporary variables should not be recorded in-line.
+     * @param level Indicates the extent to which flattening should occur.
+     */
+    export function flattenDestructuringBinding(
+        node: VariableDeclaration | ParameterDeclaration,
+        visitor: (node: Node) => VisitResult<Node>,
+        context: TransformationContext,
+        level: FlattenLevel,
+        rval?: Expression,
+        hoistTempVariables?: boolean,
+        skipInitializer?: boolean): VariableDeclaration[] {
+        let pendingExpressions: Expression[];
+        const pendingDeclarations: { pendingExpressions?: Expression[], name: BindingName, value: Expression, location?: TextRange, original?: Node; }[] = [];
+        const declarations: VariableDeclaration[] = [];
+        const flattenContext: FlattenContext = {
+            context,
+            level,
+            hoistTempVariables,
+            emitExpression,
+            emitBindingOrAssignment,
+            createArrayBindingOrAssignmentPattern: makeArrayBindingPattern,
+            createObjectBindingOrAssignmentPattern: makeObjectBindingPattern,
+            createArrayBindingOrAssignmentElement: makeBindingElement,
+            visitor
+        };
+        flattenBindingOrAssignmentElement(flattenContext, node, rval, node, skipInitializer);
+        if (pendingExpressions) {
+            const temp = createTempVariable(/*recordTempVariable*/ undefined);
+            if (hoistTempVariables) {
+                const value = inlineExpressions(pendingExpressions);
+                pendingExpressions = undefined;
+                emitBindingOrAssignment(temp, value, /*location*/ undefined, /*original*/ undefined);
+            }
+            else {
+                context.hoistVariableDeclaration(temp);
+                const pendingDeclaration = lastOrUndefined(pendingDeclarations);
+                pendingDeclaration.pendingExpressions = append(
+                    pendingDeclaration.pendingExpressions,
+                    createAssignment(temp, pendingDeclaration.value)
+                );
+                addRange(pendingDeclaration.pendingExpressions, pendingExpressions);
+                pendingDeclaration.value = temp;
+            }
+        }
+        for (const { pendingExpressions, name, value, location, original } of pendingDeclarations) {
+            const variable = createVariableDeclaration(
+                name,
+                /*type*/ undefined,
+                pendingExpressions ? inlineExpressions(append(pendingExpressions, value)) : value,
+                location);
+            variable.original = original;
+            if (isIdentifier(name)) {
+                setEmitFlags(variable, EmitFlags.NoNestedSourceMaps);
+            }
+            aggregateTransformFlags(variable);
+            declarations.push(variable);
+        }
+        return declarations;
+
+        function emitExpression(value: Expression) {
+            pendingExpressions = append(pendingExpressions, value);
+        }
+
+        function emitBindingOrAssignment(target: BindingOrAssignmentElementTarget, value: Expression, location: TextRange, original: Node) {
+            Debug.assertNode(target, isBindingName);
+            if (pendingExpressions) {
+                value = inlineExpressions(append(pendingExpressions, value));
+                pendingExpressions = undefined;
+            }
+            pendingDeclarations.push({ pendingExpressions, name: <BindingName>target, value, location, original });
+        }
+    }
+
+    /**
+     * Flattens a BindingOrAssignmentElement into zero or more bindings or assignments.
+     *
+     * @param flattenContext Options used to control flattening.
+     * @param element The element to flatten.
+     * @param value The current RHS value to assign to the element.
+     * @param location The location to use for source maps and comments.
+     * @param skipInitializer An optional value indicating whether to include the initializer
+     * for the element.
+     */
+    function flattenBindingOrAssignmentElement(
+        flattenContext: FlattenContext,
+        element: BindingOrAssignmentElement,
+        value: Expression | undefined,
         location: TextRange,
-        emitAssignment: (name: Identifier, value: Expression, location: TextRange, original: Node) => void,
-        emitTempVariableAssignment: (value: Expression, location: TextRange) => Identifier,
-        visitor?: (node: Node) => VisitResult<Node>) {
-        if (value && visitor) {
-            value = visitNode(value, visitor, isExpression);
-        }
-
-        if (isBinaryExpression(root)) {
-            emitDestructuringAssignment(root.left, value, location);
-        }
-        else {
-            emitBindingElement(root, value);
-        }
-
-        function emitDestructuringAssignment(bindingTarget: Expression | ShorthandPropertyAssignment, value: Expression, location: TextRange) {
-            // When emitting target = value use source map node to highlight, including any temporary assignments needed for this
-            let target: Expression;
-            if (isShorthandPropertyAssignment(bindingTarget)) {
-                const initializer = visitor
-                    ? visitNode(bindingTarget.objectAssignmentInitializer, visitor, isExpression)
-                    : bindingTarget.objectAssignmentInitializer;
-
-                if (initializer) {
-                    value = createDefaultValueCheck(value, initializer, location);
-                }
-
-                target = bindingTarget.name;
-            }
-            else if (isBinaryExpression(bindingTarget) && bindingTarget.operatorToken.kind === SyntaxKind.EqualsToken) {
-                const initializer = visitor
-                    ? visitNode(bindingTarget.right, visitor, isExpression)
-                    : bindingTarget.right;
-
-                value = createDefaultValueCheck(value, initializer, location);
-                target = bindingTarget.left;
-            }
-            else {
-                target = bindingTarget;
-            }
-
-            if (target.kind === SyntaxKind.ObjectLiteralExpression) {
-                emitObjectLiteralAssignment(<ObjectLiteralExpression>target, value, location);
-            }
-            else if (target.kind === SyntaxKind.ArrayLiteralExpression) {
-                emitArrayLiteralAssignment(<ArrayLiteralExpression>target, value, location);
-            }
-            else {
-                const name = getMutableClone(<Identifier>target);
-                setSourceMapRange(name, target);
-                setCommentRange(name, target);
-                emitAssignment(name, value, location, /*original*/ undefined);
-            }
-        }
-
-        function emitObjectLiteralAssignment(target: ObjectLiteralExpression, value: Expression, location: TextRange) {
-            const properties = target.properties;
-            if (properties.length !== 1) {
-                // For anything but a single element destructuring we need to generate a temporary
-                // to ensure value is evaluated exactly once.
-                // When doing so we want to hightlight the passed in source map node since thats the one needing this temp assignment
-                value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
-            }
-
-            for (const p of properties) {
-                if (p.kind === SyntaxKind.PropertyAssignment || p.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                    const propName = <Identifier | LiteralExpression>(<PropertyAssignment>p).name;
-                    const target = p.kind === SyntaxKind.ShorthandPropertyAssignment ? <ShorthandPropertyAssignment>p : (<PropertyAssignment>p).initializer || propName;
-                    // Assignment for target = value.propName should highligh whole property, hence use p as source map node
-                    emitDestructuringAssignment(target, createDestructuringPropertyAccess(value, propName), p);
-                }
-            }
-        }
-
-        function emitArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
-            const elements = target.elements;
-            const numElements = elements.length;
-            if (numElements !== 1) {
-                // For anything but a single element destructuring we need to generate a temporary
-                // to ensure value is evaluated exactly once.
-                // When doing so we want to hightlight the passed in source map node since thats the one needing this temp assignment
-                value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
-            }
-
-            for (let i = 0; i < numElements; i++) {
-                const e = elements[i];
-                if (e.kind !== SyntaxKind.OmittedExpression) {
-                    // Assignment for target = value.propName should highligh whole property, hence use e as source map node
-                    if (e.kind !== SyntaxKind.SpreadElementExpression) {
-                        emitDestructuringAssignment(e, createElementAccess(value, createLiteral(i)), e);
-                    }
-                    else if (i === numElements - 1) {
-                        emitDestructuringAssignment((<SpreadElementExpression>e).expression, createArraySlice(value, i), e);
-                    }
-                }
-            }
-        }
-
-        function emitBindingElement(target: VariableDeclaration | ParameterDeclaration | BindingElement, value: Expression) {
-            // Any temporary assignments needed to emit target = value should point to target
-            const initializer = visitor ? visitNode(target.initializer, visitor, isExpression) : target.initializer;
+        skipInitializer?: boolean) {
+        if (!skipInitializer) {
+            const initializer = visitNode(getInitializerOfBindingOrAssignmentElement(element), flattenContext.visitor, isExpression);
             if (initializer) {
                 // Combine value and initializer
-                value = value ? createDefaultValueCheck(value, initializer, target) : initializer;
+                value = value ? createDefaultValueCheck(flattenContext, value, initializer, location) : initializer;
             }
             else if (!value) {
                 // Use 'void 0' in absence of value and initializer
                 value = createVoidZero();
             }
-
-            const name = target.name;
-            if (isBindingPattern(name)) {
-                const elements = name.elements;
-                const numElements = elements.length;
-                if (numElements !== 1) {
-                    // For anything other than a single-element destructuring we need to generate a temporary
-                    // to ensure value is evaluated exactly once. Additionally, if we have zero elements
-                    // we need to emit *something* to ensure that in case a 'var' keyword was already emitted,
-                    // so in that case, we'll intentionally create that temporary.
-                    value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ numElements !== 0, target, emitTempVariableAssignment);
-                }
-                for (let i = 0; i < numElements; i++) {
-                    const element = elements[i];
-                    if (isOmittedExpression(element)) {
-                        continue;
-                    }
-                    else if (name.kind === SyntaxKind.ObjectBindingPattern) {
-                        // Rewrite element to a declaration with an initializer that fetches property
-                        const propName = element.propertyName || <Identifier>element.name;
-                        emitBindingElement(element, createDestructuringPropertyAccess(value, propName));
-                    }
-                    else {
-                        if (!element.dotDotDotToken) {
-                            // Rewrite element to a declaration that accesses array element at index i
-                            emitBindingElement(element, createElementAccess(value, i));
-                        }
-                        else if (i === numElements - 1) {
-                            emitBindingElement(element, createArraySlice(value, i));
-                        }
-                    }
-                }
-            }
-            else {
-                emitAssignment(name, value, target, target);
-            }
         }
-
-        function createDefaultValueCheck(value: Expression, defaultValue: Expression, location: TextRange): Expression {
-            value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
-            return createConditional(
-                createStrictEquality(value, createVoidZero()),
-                createToken(SyntaxKind.QuestionToken),
-                defaultValue,
-                createToken(SyntaxKind.ColonToken),
-                value
-            );
+        const bindingTarget = getTargetOfBindingOrAssignmentElement(element);
+        if (isObjectBindingOrAssignmentPattern(bindingTarget)) {
+            flattenObjectBindingOrAssignmentPattern(flattenContext, element, bindingTarget, value, location);
         }
+        else if (isArrayBindingOrAssignmentPattern(bindingTarget)) {
+            flattenArrayBindingOrAssignmentPattern(flattenContext, element, bindingTarget, value, location);
+        }
+        else {
+            flattenContext.emitBindingOrAssignment(bindingTarget, value, location, /*original*/ element);
+        }
+    }
 
-        /**
-         * Creates either a PropertyAccessExpression or an ElementAccessExpression for the
-         * right-hand side of a transformed destructuring assignment.
-         *
-         * @param expression The right-hand expression that is the source of the property.
-         * @param propertyName The destructuring property name.
-         */
-        function createDestructuringPropertyAccess(expression: Expression, propertyName: PropertyName): LeftHandSideExpression {
-            if (isComputedPropertyName(propertyName)) {
-                return createElementAccess(
-                    expression,
-                    ensureIdentifier(propertyName.expression, /*reuseIdentifierExpressions*/ false, /*location*/ propertyName, emitTempVariableAssignment)
-                );
-            }
-            else if (isLiteralExpression(propertyName)) {
-                const clone = getSynthesizedClone(propertyName);
-                clone.text = unescapeIdentifier(clone.text);
-                return createElementAccess(expression, clone);
-            }
-            else {
-                if (isGeneratedIdentifier(propertyName)) {
-                    const clone = getSynthesizedClone(propertyName);
-                    clone.text = unescapeIdentifier(clone.text);
-                    return createPropertyAccess(expression, clone);
+    /**
+     * Flattens an ObjectBindingOrAssignmentPattern into zero or more bindings or assignments.
+     *
+     * @param flattenContext Options used to control flattening.
+     * @param parent The parent element of the pattern.
+     * @param pattern The ObjectBindingOrAssignmentPattern to flatten.
+     * @param value The current RHS value to assign to the element.
+     * @param location The location to use for source maps and comments.
+     */
+    function flattenObjectBindingOrAssignmentPattern(flattenContext: FlattenContext, parent: BindingOrAssignmentElement, pattern: ObjectBindingOrAssignmentPattern, value: Expression, location: TextRange) {
+        const elements = getElementsOfBindingOrAssignmentPattern(pattern);
+        const numElements = elements.length;
+        if (numElements !== 1) {
+            // For anything other than a single-element destructuring we need to generate a temporary
+            // to ensure value is evaluated exactly once. Additionally, if we have zero elements
+            // we need to emit *something* to ensure that in case a 'var' keyword was already emitted,
+            // so in that case, we'll intentionally create that temporary.
+            const reuseIdentifierExpressions = !isDeclarationBindingElement(parent) || numElements !== 0;
+            value = ensureIdentifier(flattenContext, value, reuseIdentifierExpressions, location);
+        }
+        let bindingElements: BindingOrAssignmentElement[];
+        let computedTempVariables: Expression[];
+        for (let i = 0; i < numElements; i++) {
+            const element = elements[i];
+            if (!getRestIndicatorOfBindingOrAssignmentElement(element)) {
+                const propertyName = getPropertyNameOfBindingOrAssignmentElement(element);
+                if (flattenContext.level >= FlattenLevel.ObjectRest
+                    && !(element.transformFlags & (TransformFlags.ContainsRest | TransformFlags.ContainsObjectRest))
+                    && !(getTargetOfBindingOrAssignmentElement(element).transformFlags & (TransformFlags.ContainsRest | TransformFlags.ContainsObjectRest))
+                    && !isComputedPropertyName(propertyName)) {
+                    bindingElements = append(bindingElements, element);
                 }
                 else {
-                    return createPropertyAccess(expression, createIdentifier(unescapeIdentifier(propertyName.text)));
+                    if (bindingElements) {
+                        flattenContext.emitBindingOrAssignment(flattenContext.createObjectBindingOrAssignmentPattern(bindingElements), value, location, pattern);
+                        bindingElements = undefined;
+                    }
+                    const rhsValue = createDestructuringPropertyAccess(flattenContext, value, propertyName);
+                    if (isComputedPropertyName(propertyName)) {
+                        computedTempVariables = append(computedTempVariables, (rhsValue as ElementAccessExpression).argumentExpression);
+                    }
+                    flattenBindingOrAssignmentElement(flattenContext, element, rhsValue, /*location*/ element);
                 }
             }
+            else if (i === numElements - 1) {
+                if (bindingElements) {
+                    flattenContext.emitBindingOrAssignment(flattenContext.createObjectBindingOrAssignmentPattern(bindingElements), value, location, pattern);
+                    bindingElements = undefined;
+                }
+                const rhsValue = createRestCall(flattenContext.context, value, elements, computedTempVariables, pattern);
+                flattenBindingOrAssignmentElement(flattenContext, element, rhsValue, element);
+            }
+        }
+        if (bindingElements) {
+            flattenContext.emitBindingOrAssignment(flattenContext.createObjectBindingOrAssignmentPattern(bindingElements), value, location, pattern);
+        }
+    }
+
+    /**
+     * Flattens an ArrayBindingOrAssignmentPattern into zero or more bindings or assignments.
+     *
+     * @param flattenContext Options used to control flattening.
+     * @param parent The parent element of the pattern.
+     * @param pattern The ArrayBindingOrAssignmentPattern to flatten.
+     * @param value The current RHS value to assign to the element.
+     * @param location The location to use for source maps and comments.
+     */
+    function flattenArrayBindingOrAssignmentPattern(flattenContext: FlattenContext, parent: BindingOrAssignmentElement, pattern: ArrayBindingOrAssignmentPattern, value: Expression, location: TextRange) {
+        const elements = getElementsOfBindingOrAssignmentPattern(pattern);
+        const numElements = elements.length;
+        if (numElements !== 1 && (flattenContext.level < FlattenLevel.ObjectRest || numElements === 0)) {
+            // For anything other than a single-element destructuring we need to generate a temporary
+            // to ensure value is evaluated exactly once. Additionally, if we have zero elements
+            // we need to emit *something* to ensure that in case a 'var' keyword was already emitted,
+            // so in that case, we'll intentionally create that temporary.
+            const reuseIdentifierExpressions = !isDeclarationBindingElement(parent) || numElements !== 0;
+            value = ensureIdentifier(flattenContext, value, reuseIdentifierExpressions, location);
+        }
+        let bindingElements: BindingOrAssignmentElement[];
+        let restContainingElements: [Identifier, BindingOrAssignmentElement][];
+        for (let i = 0; i < numElements; i++) {
+            const element = elements[i];
+            if (flattenContext.level >= FlattenLevel.ObjectRest) {
+                // If an array pattern contains an ObjectRest, we must cache the result so that we
+                // can perform the ObjectRest destructuring in a different declaration
+                if (element.transformFlags & TransformFlags.ContainsObjectRest) {
+                    const temp = createTempVariable(/*recordTempVariable*/ undefined);
+                    if (flattenContext.hoistTempVariables) {
+                        flattenContext.context.hoistVariableDeclaration(temp);
+                    }
+
+                    restContainingElements = append(restContainingElements, <[Identifier, BindingOrAssignmentElement]>[temp, element]);
+                    bindingElements = append(bindingElements, flattenContext.createArrayBindingOrAssignmentElement(temp));
+                }
+                else {
+                    bindingElements = append(bindingElements, element);
+                }
+            }
+            else if (isOmittedExpression(element)) {
+                continue;
+            }
+            else if (!getRestIndicatorOfBindingOrAssignmentElement(element)) {
+                const rhsValue = createElementAccess(value, i);
+                flattenBindingOrAssignmentElement(flattenContext, element, rhsValue, /*location*/ element);
+            }
+            else if (i === numElements - 1) {
+                const rhsValue = createArraySlice(value, i);
+                flattenBindingOrAssignmentElement(flattenContext, element, rhsValue, /*location*/ element);
+            }
+        }
+        if (bindingElements) {
+            flattenContext.emitBindingOrAssignment(flattenContext.createArrayBindingOrAssignmentPattern(bindingElements), value, location, pattern);
+        }
+        if (restContainingElements) {
+            for (const [id, element] of restContainingElements) {
+                flattenBindingOrAssignmentElement(flattenContext, element, id, element);
+            }
+        }
+    }
+
+    /**
+     * Creates an expression used to provide a default value if a value is `undefined` at runtime.
+     *
+     * @param flattenContext Options used to control flattening.
+     * @param value The RHS value to test.
+     * @param defaultValue The default value to use if `value` is `undefined` at runtime.
+     * @param location The location to use for source maps and comments.
+     */
+    function createDefaultValueCheck(flattenContext: FlattenContext, value: Expression, defaultValue: Expression, location: TextRange): Expression {
+        value = ensureIdentifier(flattenContext, value, /*reuseIdentifierExpressions*/ true, location);
+        return createConditional(createTypeCheck(value, "undefined"), defaultValue, value);
+    }
+
+    /**
+     * Creates either a PropertyAccessExpression or an ElementAccessExpression for the
+     * right-hand side of a transformed destructuring assignment.
+     *
+     * @link https://tc39.github.io/ecma262/#sec-runtime-semantics-keyeddestructuringassignmentevaluation
+     *
+     * @param flattenContext Options used to control flattening.
+     * @param value The RHS value that is the source of the property.
+     * @param propertyName The destructuring property name.
+     */
+    function createDestructuringPropertyAccess(flattenContext: FlattenContext, value: Expression, propertyName: PropertyName): LeftHandSideExpression {
+        if (isComputedPropertyName(propertyName)) {
+            const argumentExpression = ensureIdentifier(flattenContext, propertyName.expression, /*reuseIdentifierExpressions*/ false, /*location*/ propertyName);
+            return createElementAccess(value, argumentExpression);
+        }
+        else if (isStringOrNumericLiteral(propertyName)) {
+            const argumentExpression = getSynthesizedClone(propertyName);
+            argumentExpression.text = unescapeIdentifier(argumentExpression.text);
+            return createElementAccess(value, argumentExpression);
+        }
+        else {
+            const name = createIdentifier(unescapeIdentifier(propertyName.text));
+            return createPropertyAccess(value, name);
         }
     }
 
@@ -415,29 +402,96 @@ namespace ts {
      * This function is useful to ensure that the expression's value can be read from in subsequent expressions.
      * Unless 'reuseIdentifierExpressions' is false, 'value' will be returned if it is just an identifier.
      *
+     * @param flattenContext Options used to control flattening.
      * @param value the expression whose value needs to be bound.
      * @param reuseIdentifierExpressions true if identifier expressions can simply be returned;
-     *                                   false if it is necessary to always emit an identifier.
+     * false if it is necessary to always emit an identifier.
      * @param location The location to use for source maps and comments.
-     * @param emitTempVariableAssignment A callback used to emit a temporary variable.
-     * @param visitor An optional callback used to visit the value.
      */
-    function ensureIdentifier(
-        value: Expression,
-        reuseIdentifierExpressions: boolean,
-        location: TextRange,
-        emitTempVariableAssignment: (value: Expression, location: TextRange) => Identifier,
-        visitor?: (node: Node) => VisitResult<Node>) {
-
+    function ensureIdentifier(flattenContext: FlattenContext, value: Expression, reuseIdentifierExpressions: boolean, location: TextRange) {
         if (isIdentifier(value) && reuseIdentifierExpressions) {
             return value;
         }
         else {
-            if (visitor) {
-                value = visitNode(value, visitor, isExpression);
+            const temp = createTempVariable(/*recordTempVariable*/ undefined);
+            if (flattenContext.hoistTempVariables) {
+                flattenContext.context.hoistVariableDeclaration(temp);
+                flattenContext.emitExpression(createAssignment(temp, value, location));
             }
-
-            return emitTempVariableAssignment(value, location);
+            else {
+                flattenContext.emitBindingOrAssignment(temp, value, location, /*original*/ undefined);
+            }
+            return temp;
         }
     }
+
+    function makeArrayBindingPattern(elements: BindingOrAssignmentElement[]) {
+        Debug.assertEachNode(elements, isArrayBindingElement);
+        return createArrayBindingPattern(<ArrayBindingElement[]>elements);
+    }
+
+    function makeArrayAssignmentPattern(elements: BindingOrAssignmentElement[]) {
+        return createArrayLiteral(map(elements, convertToArrayAssignmentElement));
+    }
+
+    function makeObjectBindingPattern(elements: BindingOrAssignmentElement[]) {
+        Debug.assertEachNode(elements, isBindingElement);
+        return createObjectBindingPattern(<BindingElement[]>elements);
+    }
+
+    function makeObjectAssignmentPattern(elements: BindingOrAssignmentElement[]) {
+        return createObjectLiteral(map(elements, convertToObjectAssignmentElement));
+    }
+
+    function makeBindingElement(name: Identifier) {
+        return createBindingElement(/*propertyName*/ undefined, /*dotDotDotToken*/ undefined, name);
+    }
+
+    function makeAssignmentElement(name: Identifier) {
+        return name;
+    }
+
+    const restHelper: EmitHelper = {
+        name: "typescript:rest",
+        scoped: false,
+        text: `
+            var __rest = (this && this.__rest) || function (s, e) {
+                var t = {};
+                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
+                    t[p] = s[p];
+                if (s != null && typeof Object.getOwnPropertySymbols === "function")
+                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
+                        t[p[i]] = s[p[i]];
+                return t;
+            };`
+    };
+
+    /** Given value: o, propName: p, pattern: { a, b, ...p } from the original statement
+     * `{ a, b, ...p } = o`, create `p = __rest(o, ["a", "b"]);`*/
+    function createRestCall(context: TransformationContext, value: Expression, elements: BindingOrAssignmentElement[], computedTempVariables: Expression[], location: TextRange): Expression {
+        context.requestEmitHelper(restHelper);
+        const propertyNames: Expression[] = [];
+        let computedTempVariableOffset = 0;
+        for (let i = 0; i < elements.length - 1; i++) {
+            const propertyName = getPropertyNameOfBindingOrAssignmentElement(elements[i]);
+            if (propertyName) {
+                if (isComputedPropertyName(propertyName)) {
+                    const temp = computedTempVariables[computedTempVariableOffset];
+                    computedTempVariableOffset++;
+                    // typeof _tmp === "symbol" ? _tmp : _tmp + ""
+                    propertyNames.push(
+                        createConditional(
+                            createTypeCheck(temp, "symbol"),
+                            temp,
+                            createAdd(temp, createLiteral(""))
+                        )
+                    );
+                }
+                else {
+                    propertyNames.push(createLiteral(propertyName));
+                }
+            }
+        }
+        return createCall(getHelperName("__rest"), undefined, [value, createArrayLiteral(propertyNames, location)]);
+    }
 }

src/compiler/transformers/es2016.ts

@@ -17,85 +17,75 @@ namespace ts {
         }
 
         function visitor(node: Node): VisitResult<Node> {
-            if (node.transformFlags & TransformFlags.ES2016) {
-                return visitorWorker(node);
-            }
-            else if (node.transformFlags & TransformFlags.ContainsES2016) {
-                return visitEachChild(node, visitor, context);
-            }
-            else {
+            if ((node.transformFlags & TransformFlags.ContainsES2016) === 0) {
                 return node;
             }
-        }
-
-        function visitorWorker(node: Node): VisitResult<Node> {
             switch (node.kind) {
                 case SyntaxKind.BinaryExpression:
                     return visitBinaryExpression(<BinaryExpression>node);
-
                 default:
-                    Debug.failBadSyntaxKind(node);
                     return visitEachChild(node, visitor, context);
             }
         }
 
         function visitBinaryExpression(node: BinaryExpression): Expression {
-            // We are here because ES2016 adds support for the exponentiation operator.
+            switch (node.operatorToken.kind) {
+                case SyntaxKind.AsteriskAsteriskEqualsToken:
+                    return visitExponentiationAssignmentExpression(node);
+                case SyntaxKind.AsteriskAsteriskToken:
+                    return visitExponentiationExpression(node);
+                default:
+                    return visitEachChild(node, visitor, context);
+            }
+        }
+
+        function visitExponentiationAssignmentExpression(node: BinaryExpression) {
+            let target: Expression;
+            let value: Expression;
             const left = visitNode(node.left, visitor, isExpression);
             const right = visitNode(node.right, visitor, isExpression);
-            if (node.operatorToken.kind === SyntaxKind.AsteriskAsteriskEqualsToken) {
-                let target: Expression;
-                let value: Expression;
-                if (isElementAccessExpression(left)) {
-                    // Transforms `a[x] **= b` into `(_a = a)[_x = x] = Math.pow(_a[_x], b)`
-                    const expressionTemp = createTempVariable(hoistVariableDeclaration);
-
-                    const argumentExpressionTemp = createTempVariable(hoistVariableDeclaration);
-
-                    target = createElementAccess(
-                        createAssignment(expressionTemp, left.expression, /*location*/ left.expression),
-                        createAssignment(argumentExpressionTemp, left.argumentExpression, /*location*/ left.argumentExpression),
-                        /*location*/ left
-                    );
-
-                    value = createElementAccess(
-                        expressionTemp,
-                        argumentExpressionTemp,
-                        /*location*/ left
-                    );
-                }
-                else if (isPropertyAccessExpression(left)) {
-                    // Transforms `a.x **= b` into `(_a = a).x = Math.pow(_a.x, b)`
-                    const expressionTemp = createTempVariable(hoistVariableDeclaration);
-
-                    target = createPropertyAccess(
-                        createAssignment(expressionTemp, left.expression, /*location*/ left.expression),
-                        left.name,
-                        /*location*/ left
-                    );
-
-                    value = createPropertyAccess(
-                        expressionTemp,
-                        left.name,
-                        /*location*/ left
-                    );
-                }
-                else {
-                    // Transforms `a **= b` into `a = Math.pow(a, b)`
-                    target = left;
-                    value = left;
-                }
-
-                return createAssignment(target, createMathPow(value, right, /*location*/ node), /*location*/ node);
+            if (isElementAccessExpression(left)) {
+                // Transforms `a[x] **= b` into `(_a = a)[_x = x] = Math.pow(_a[_x], b)`
+                const expressionTemp = createTempVariable(hoistVariableDeclaration);
+                const argumentExpressionTemp = createTempVariable(hoistVariableDeclaration);
+                target = createElementAccess(
+                    createAssignment(expressionTemp, left.expression, /*location*/ left.expression),
+                    createAssignment(argumentExpressionTemp, left.argumentExpression, /*location*/ left.argumentExpression),
+                    /*location*/ left
+                );
+                value = createElementAccess(
+                    expressionTemp,
+                    argumentExpressionTemp,
+                    /*location*/ left
+                );
             }
-            else if (node.operatorToken.kind === SyntaxKind.AsteriskAsteriskToken) {
-                // Transforms `a ** b` into `Math.pow(a, b)`
-                return createMathPow(left, right, /*location*/ node);
+            else if (isPropertyAccessExpression(left)) {
+                // Transforms `a.x **= b` into `(_a = a).x = Math.pow(_a.x, b)`
+                const expressionTemp = createTempVariable(hoistVariableDeclaration);
+                target = createPropertyAccess(
+                    createAssignment(expressionTemp, left.expression, /*location*/ left.expression),
+                    left.name,
+                    /*location*/ left
+                );
+                value = createPropertyAccess(
+                    expressionTemp,
+                    left.name,
+                    /*location*/ left
+                );
             }
             else {
-                Debug.failBadSyntaxKind(node);
-                return visitEachChild(node, visitor, context);
+                // Transforms `a **= b` into `a = Math.pow(a, b)`
+                target = left;
+                value = left;
             }
+            return createAssignment(target, createMathPow(value, right, /*location*/ node), /*location*/ node);
+        }
+
+        function visitExponentiationExpression(node: BinaryExpression) {
+            // Transforms `a ** b` into `Math.pow(a, b)`
+            const left = visitNode(node.left, visitor, isExpression);
+            const right = visitNode(node.right, visitor, isExpression);
+            return createMathPow(left, right, /*location*/ node);
         }
     }
 }

src/compiler/transformers/es2017.ts

@@ -5,15 +5,15 @@
 namespace ts {
     type SuperContainer = ClassDeclaration | MethodDeclaration | GetAccessorDeclaration | SetAccessorDeclaration | ConstructorDeclaration;
 
+    const enum ES2017SubstitutionFlags {
+        /** Enables substitutions for async methods with `super` calls. */
+        AsyncMethodsWithSuper = 1 << 0
+    }
+
     export function transformES2017(context: TransformationContext) {
-
-        const enum ES2017SubstitutionFlags {
-            /** Enables substitutions for async methods with `super` calls. */
-            AsyncMethodsWithSuper = 1 << 0
-        }
-
         const {
             startLexicalEnvironment,
+            resumeLexicalEnvironment,
             endLexicalEnvironment,
         } = context;
 
@@ -22,19 +22,14 @@ namespace ts {
         const languageVersion = getEmitScriptTarget(compilerOptions);
 
         // These variables contain state that changes as we descend into the tree.
-        let currentSourceFileExternalHelpersModuleName: Identifier;
+        let currentSourceFile: SourceFile;
+
         /**
          * Keeps track of whether expression substitution has been enabled for specific edge cases.
          * They are persisted between each SourceFile transformation and should not be reset.
          */
         let enabledSubstitutions: ES2017SubstitutionFlags;
 
-        /**
-         * Keeps track of whether  we are within any containing namespaces when performing
-         * just-in-time substitution while printing an expression identifier.
-         */
-        let applicableSubstitutions: ES2017SubstitutionFlags;
-
         /**
          * This keeps track of containers where `super` is valid, for use with
          * just-in-time substitution for `super` expressions inside of async methods.
@@ -49,8 +44,6 @@ namespace ts {
         context.onEmitNode = onEmitNode;
         context.onSubstituteNode = onSubstituteNode;
 
-        let currentScope: SourceFile | Block | ModuleBlock | CaseBlock;
-
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
@@ -58,23 +51,20 @@ namespace ts {
                 return node;
             }
 
-            currentSourceFileExternalHelpersModuleName = node.externalHelpersModuleName;
+            currentSourceFile = node;
 
-            return visitEachChild(node, visitor, context);
+            const visited = visitEachChild(node, visitor, context);
+            addEmitHelpers(visited, context.readEmitHelpers());
+
+            currentSourceFile = undefined;
+            return visited;
         }
 
         function visitor(node: Node): VisitResult<Node> {
-            if (node.transformFlags & TransformFlags.ES2017) {
-                return visitorWorker(node);
-            }
-            else if (node.transformFlags & TransformFlags.ContainsES2017) {
-                return visitEachChild(node, visitor, context);
+            if ((node.transformFlags & TransformFlags.ContainsES2017) === 0) {
+                return node;
             }
 
-            return node;
-        }
-
-        function visitorWorker(node: Node): VisitResult<Node> {
             switch (node.kind) {
                 case SyntaxKind.AsyncKeyword:
                     // ES2017 async modifier should be elided for targets < ES2017
@@ -101,17 +91,16 @@ namespace ts {
                     return visitArrowFunction(<ArrowFunction>node);
 
                 default:
-                    Debug.failBadSyntaxKind(node);
-                    return node;
+                    return visitEachChild(node, visitor, context);
             }
         }
 
         /**
-         * Visits an await expression.
+         * Visits an AwaitExpression node.
          *
          * This function will be called any time a ES2017 await expression is encountered.
          *
-         * @param node The await expression node.
+         * @param node The node to visit.
          */
         function visitAwaitExpression(node: AwaitExpression): Expression {
             return setOriginalNode(
@@ -125,143 +114,102 @@ namespace ts {
         }
 
         /**
-         * Visits a method declaration of a class.
+         * Visits a MethodDeclaration node.
          *
          * This function will be called when one of the following conditions are met:
          * - The node is marked as async
          *
-         * @param node The method node.
+         * @param node The node to visit.
          */
         function visitMethodDeclaration(node: MethodDeclaration) {
-            if (!isAsyncFunctionLike(node)) {
-                return node;
-            }
-            const method = createMethod(
+            return updateMethod(
+                node,
                 /*decorators*/ undefined,
                 visitNodes(node.modifiers, visitor, isModifier),
-                node.asteriskToken,
                 node.name,
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                transformFunctionBody(node),
-                /*location*/ node
+                isAsyncFunctionLike(node)
+                    ? transformAsyncFunctionBody(node)
+                    : visitFunctionBody(node.body, visitor, context)
             );
-
-            // While we emit the source map for the node after skipping decorators and modifiers,
-            // we need to emit the comments for the original range.
-            setCommentRange(method, node);
-            setSourceMapRange(method, moveRangePastDecorators(node));
-            setOriginalNode(method, node);
-
-            return method;
         }
 
         /**
-         * Visits a function declaration.
+         * Visits a FunctionDeclaration node.
          *
          * This function will be called when one of the following conditions are met:
          * - The node is marked async
          *
-         * @param node The function node.
+         * @param node The node to visit.
          */
         function visitFunctionDeclaration(node: FunctionDeclaration): VisitResult<Statement> {
-            if (!isAsyncFunctionLike(node)) {
-                return node;
-            }
-            const func = createFunctionDeclaration(
+            return updateFunctionDeclaration(
+                node,
                 /*decorators*/ undefined,
                 visitNodes(node.modifiers, visitor, isModifier),
-                node.asteriskToken,
                 node.name,
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                transformFunctionBody(node),
-                /*location*/ node
+                isAsyncFunctionLike(node)
+                    ? transformAsyncFunctionBody(node)
+                    : visitFunctionBody(node.body, visitor, context)
             );
-            setOriginalNode(func, node);
-
-            return func;
         }
 
         /**
-         * Visits a function expression node.
+         * Visits a FunctionExpression node.
          *
          * This function will be called when one of the following conditions are met:
          * - The node is marked async
          *
-         * @param node The function expression node.
+         * @param node The node to visit.
          */
         function visitFunctionExpression(node: FunctionExpression): Expression {
-            if (!isAsyncFunctionLike(node)) {
-                return node;
-            }
             if (nodeIsMissing(node.body)) {
                 return createOmittedExpression();
             }
-
-            const func = createFunctionExpression(
+            return updateFunctionExpression(
+                node,
                 /*modifiers*/ undefined,
-                node.asteriskToken,
                 node.name,
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                transformFunctionBody(node),
-                /*location*/ node
+                isAsyncFunctionLike(node)
+                    ? transformAsyncFunctionBody(node)
+                    : visitFunctionBody(node.body, visitor, context)
             );
-
-            setOriginalNode(func, node);
-
-            return func;
         }
 
         /**
-         * @remarks
+         * Visits an ArrowFunction.
+         *
          * This function will be called when one of the following conditions are met:
          * - The node is marked async
+         *
+         * @param node The node to visit.
          */
         function visitArrowFunction(node: ArrowFunction) {
-            if (!isAsyncFunctionLike(node)) {
-                return node;
-            }
-            const func = createArrowFunction(
+            return updateArrowFunction(
+                node,
                 visitNodes(node.modifiers, visitor, isModifier),
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                node.equalsGreaterThanToken,
-                transformConciseBody(node),
-                /*location*/ node
+                isAsyncFunctionLike(node)
+                    ? transformAsyncFunctionBody(node)
+                    : visitFunctionBody(node.body, visitor, context)
             );
-
-            setOriginalNode(func, node);
-
-            return func;
         }
 
-        function transformFunctionBody(node: MethodDeclaration | AccessorDeclaration | FunctionDeclaration | FunctionExpression): FunctionBody {
-            return <FunctionBody>transformAsyncFunctionBody(node);
-        }
+        function transformAsyncFunctionBody(node: MethodDeclaration | AccessorDeclaration | FunctionDeclaration | FunctionExpression): FunctionBody;
+        function transformAsyncFunctionBody(node: ArrowFunction): ConciseBody;
+        function transformAsyncFunctionBody(node: FunctionLikeDeclaration): ConciseBody {
+            resumeLexicalEnvironment();
 
-        function transformConciseBody(node: ArrowFunction): ConciseBody {
-            return transformAsyncFunctionBody(node);
-        }
-
-        function transformFunctionBodyWorker(body: Block, start = 0) {
-            const savedCurrentScope = currentScope;
-            currentScope = body;
-            startLexicalEnvironment();
-
-            const statements = visitNodes(body.statements, visitor, isStatement, start);
-            const visited = updateBlock(body, statements);
-            const declarations = endLexicalEnvironment();
-            currentScope = savedCurrentScope;
-            return mergeFunctionBodyLexicalEnvironment(visited, declarations);
-        }
-
-        function transformAsyncFunctionBody(node: FunctionLikeDeclaration): ConciseBody | FunctionBody {
             const original = getOriginalNode(node, isFunctionLike);
             const nodeType = original.type;
             const promiseConstructor = languageVersion < ScriptTarget.ES2015 ? getPromiseConstructor(nodeType) : undefined;
@@ -274,14 +222,13 @@ namespace ts {
             // passed to `__awaiter` is executed inside of the callback to the
             // promise constructor.
 
-
             if (!isArrowFunction) {
                 const statements: Statement[] = [];
                 const statementOffset = addPrologueDirectives(statements, (<Block>node.body).statements, /*ensureUseStrict*/ false, visitor);
                 statements.push(
                     createReturn(
                         createAwaiterHelper(
-                            currentSourceFileExternalHelpersModuleName,
+                            context,
                             hasLexicalArguments,
                             promiseConstructor,
                             transformFunctionBodyWorker(<Block>node.body, statementOffset)
@@ -289,6 +236,8 @@ namespace ts {
                     )
                 );
 
+                addRange(statements, endLexicalEnvironment());
+
                 const block = createBlock(statements, /*location*/ node.body, /*multiLine*/ true);
 
                 // Minor optimization, emit `_super` helper to capture `super` access in an arrow.
@@ -296,57 +245,56 @@ namespace ts {
                 if (languageVersion >= ScriptTarget.ES2015) {
                     if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.AsyncMethodWithSuperBinding) {
                         enableSubstitutionForAsyncMethodsWithSuper();
-                        setEmitFlags(block, EmitFlags.EmitAdvancedSuperHelper);
+                        addEmitHelper(block, advancedAsyncSuperHelper);
                     }
                     else if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.AsyncMethodWithSuper) {
                         enableSubstitutionForAsyncMethodsWithSuper();
-                        setEmitFlags(block, EmitFlags.EmitSuperHelper);
+                        addEmitHelper(block, asyncSuperHelper);
                     }
                 }
 
                 return block;
             }
             else {
-                return createAwaiterHelper(
-                    currentSourceFileExternalHelpersModuleName,
+                const expression = createAwaiterHelper(
+                    context,
                     hasLexicalArguments,
                     promiseConstructor,
-                    <Block>transformConciseBodyWorker(node.body, /*forceBlockFunctionBody*/ true)
+                    transformFunctionBodyWorker(node.body)
                 );
+
+                const declarations = endLexicalEnvironment();
+                if (some(declarations)) {
+                    const block = convertToFunctionBody(expression);
+                    return updateBlock(block, createNodeArray(concatenate(block.statements, declarations), block.statements));
+                }
+
+                return expression;
             }
         }
 
-        function transformConciseBodyWorker(body: Block | Expression, forceBlockFunctionBody: boolean) {
+        function transformFunctionBodyWorker(body: ConciseBody, start?: number) {
             if (isBlock(body)) {
-                return transformFunctionBodyWorker(body);
+                return updateBlock(body, visitLexicalEnvironment(body.statements, visitor, context, start));
             }
             else {
                 startLexicalEnvironment();
-                const visited: Expression | Block = visitNode(body, visitor, isConciseBody);
+                const visited = convertToFunctionBody(visitNode(body, visitor, isConciseBody));
                 const declarations = endLexicalEnvironment();
-                const merged = mergeFunctionBodyLexicalEnvironment(visited, declarations);
-                if (forceBlockFunctionBody && !isBlock(merged)) {
-                    return createBlock([
-                        createReturn(<Expression>merged)
-                    ]);
-                }
-                else {
-                    return merged;
-                }
+                return updateBlock(visited, createNodeArray(concatenate(visited.statements, declarations), visited.statements));
             }
         }
 
         function getPromiseConstructor(type: TypeNode) {
-            if (type) {
-                const typeName = getEntityNameFromTypeNode(type);
-                if (typeName && isEntityName(typeName)) {
-                    const serializationKind = resolver.getTypeReferenceSerializationKind(typeName);
-                    if (serializationKind === TypeReferenceSerializationKind.TypeWithConstructSignatureAndValue
-                        || serializationKind === TypeReferenceSerializationKind.Unknown) {
-                        return typeName;
-                    }
+            const typeName = type && getEntityNameFromTypeNode(type);
+            if (typeName && isEntityName(typeName)) {
+                const serializationKind = resolver.getTypeReferenceSerializationKind(typeName);
+                if (serializationKind === TypeReferenceSerializationKind.TypeWithConstructSignatureAndValue
+                    || serializationKind === TypeReferenceSerializationKind.Unknown) {
+                    return typeName;
                 }
             }
+
             return undefined;
         }
 
@@ -452,18 +400,17 @@ namespace ts {
          * @param emit A callback used to emit the node in the printer.
          */
         function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
-            const savedApplicableSubstitutions = applicableSubstitutions;
-            const savedCurrentSuperContainer = currentSuperContainer;
             // If we need to support substitutions for `super` in an async method,
             // we should track it here.
             if (enabledSubstitutions & ES2017SubstitutionFlags.AsyncMethodsWithSuper && isSuperContainer(node)) {
+                const savedCurrentSuperContainer = currentSuperContainer;
                 currentSuperContainer = node;
+                previousOnEmitNode(emitContext, node, emitCallback);
+                currentSuperContainer = savedCurrentSuperContainer;
+            }
+            else {
+                previousOnEmitNode(emitContext, node, emitCallback);
             }
-
-            previousOnEmitNode(emitContext, node, emitCallback);
-
-            applicableSubstitutions = savedApplicableSubstitutions;
-            currentSuperContainer = savedCurrentSuperContainer;
         }
 
         /**
@@ -509,4 +456,63 @@ namespace ts {
                 && resolver.getNodeCheckFlags(currentSuperContainer) & (NodeCheckFlags.AsyncMethodWithSuper | NodeCheckFlags.AsyncMethodWithSuperBinding);
         }
     }
+
+    function createAwaiterHelper(context: TransformationContext, hasLexicalArguments: boolean, promiseConstructor: EntityName | Expression, body: Block) {
+        context.requestEmitHelper(awaiterHelper);
+        const generatorFunc = createFunctionExpression(
+            /*modifiers*/ undefined,
+            createToken(SyntaxKind.AsteriskToken),
+            /*name*/ undefined,
+            /*typeParameters*/ undefined,
+            /*parameters*/ [],
+            /*type*/ undefined,
+            body
+        );
+
+        // Mark this node as originally an async function
+        (generatorFunc.emitNode || (generatorFunc.emitNode = {})).flags |= EmitFlags.AsyncFunctionBody;
+
+        return createCall(
+            getHelperName("__awaiter"),
+            /*typeArguments*/ undefined,
+            [
+                createThis(),
+                hasLexicalArguments ? createIdentifier("arguments") : createVoidZero(),
+                promiseConstructor ? createExpressionFromEntityName(promiseConstructor) : createVoidZero(),
+                generatorFunc
+            ]
+        );
+    }
+
+    const awaiterHelper: EmitHelper = {
+        name: "typescript:awaiter",
+        scoped: false,
+        priority: 5,
+        text: `
+            var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+                return new (P || (P = Promise))(function (resolve, reject) {
+                    function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+                    function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+                    function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+                    step((generator = generator.apply(thisArg, _arguments || [])).next());
+                });
+            };`
+    };
+
+    const asyncSuperHelper: EmitHelper = {
+        name: "typescript:async-super",
+        scoped: true,
+        text: `
+            const _super = name => super[name];`
+    };
+
+    const advancedAsyncSuperHelper: EmitHelper = {
+        name: "typescript:advanced-async-super",
+        scoped: true,
+        text: `
+            const _super = (function (geti, seti) {
+                const cache = Object.create(null);
+                return name => cache[name] || (cache[name] = { get value() { return geti(name); }, set value(v) { seti(name, v); } });
+            })(name => super[name], (name, value) => super[name] = value);`
+    };
 }

src/compiler/transformers/es5.ts

@@ -9,6 +9,20 @@ namespace ts {
      * @param context Context and state information for the transformation.
      */
     export function transformES5(context: TransformationContext) {
+        const compilerOptions = context.getCompilerOptions();
+
+        // enable emit notification only if using --jsx preserve
+        let previousOnEmitNode: (emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void) => void;
+        let noSubstitution: boolean[];
+        if (compilerOptions.jsx === JsxEmit.Preserve) {
+            previousOnEmitNode = context.onEmitNode;
+            context.onEmitNode = onEmitNode;
+            context.enableEmitNotification(SyntaxKind.JsxOpeningElement);
+            context.enableEmitNotification(SyntaxKind.JsxClosingElement);
+            context.enableEmitNotification(SyntaxKind.JsxSelfClosingElement);
+            noSubstitution = [];
+        }
+
         const previousOnSubstituteNode = context.onSubstituteNode;
         context.onSubstituteNode = onSubstituteNode;
         context.enableSubstitution(SyntaxKind.PropertyAccessExpression);
@@ -24,6 +38,24 @@ namespace ts {
             return node;
         }
 
+        /**
+         * Called by the printer just before a node is printed.
+         *
+         * @param node The node to be printed.
+         */
+        function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void) {
+            switch (node.kind) {
+                case SyntaxKind.JsxOpeningElement:
+                case SyntaxKind.JsxClosingElement:
+                case SyntaxKind.JsxSelfClosingElement:
+                    const tagName = (<JsxOpeningElement | JsxClosingElement | JsxSelfClosingElement>node).tagName;
+                    noSubstitution[getOriginalNodeId(tagName)] = true;
+                    break;
+            }
+
+            previousOnEmitNode(emitContext, node, emitCallback);
+        }
+
         /**
          * Hooks node substitutions.
          *
@@ -31,6 +63,10 @@ namespace ts {
          * @param node The node to substitute.
          */
         function onSubstituteNode(emitContext: EmitContext, node: Node) {
+            if (node.id && noSubstitution && noSubstitution[node.id]) {
+                return previousOnSubstituteNode(emitContext, node);
+            }
+
             node = previousOnSubstituteNode(emitContext, node);
             if (isPropertyAccessExpression(node)) {
                 return substitutePropertyAccessExpression(node);

src/compiler/transformers/esnext.ts

@@ -0,0 +1,412 @@
+/// <reference path="../factory.ts" />
+/// <reference path="../visitor.ts" />
+
+/*@internal*/
+namespace ts {
+    export function transformESNext(context: TransformationContext) {
+        const {
+            resumeLexicalEnvironment,
+            endLexicalEnvironment
+        } = context;
+        return transformSourceFile;
+
+        function transformSourceFile(node: SourceFile) {
+            if (isDeclarationFile(node)) {
+                return node;
+            }
+
+            const visited = visitEachChild(node, visitor, context);
+            addEmitHelpers(visited, context.readEmitHelpers());
+            return visited;
+        }
+
+        function visitor(node: Node): VisitResult<Node> {
+            return visitorWorker(node, /*noDestructuringValue*/ false);
+        }
+
+        function visitorNoDestructuringValue(node: Node): VisitResult<Node> {
+            return visitorWorker(node, /*noDestructuringValue*/ true);
+        }
+
+        function visitorWorker(node: Node, noDestructuringValue: boolean): VisitResult<Node> {
+            if ((node.transformFlags & TransformFlags.ContainsESNext) === 0) {
+                return node;
+            }
+
+            switch (node.kind) {
+                case SyntaxKind.ObjectLiteralExpression:
+                    return visitObjectLiteralExpression(node as ObjectLiteralExpression);
+                case SyntaxKind.BinaryExpression:
+                    return visitBinaryExpression(node as BinaryExpression, noDestructuringValue);
+                case SyntaxKind.VariableDeclaration:
+                    return visitVariableDeclaration(node as VariableDeclaration);
+                case SyntaxKind.ForOfStatement:
+                    return visitForOfStatement(node as ForOfStatement);
+                case SyntaxKind.ForStatement:
+                    return visitForStatement(node as ForStatement);
+                case SyntaxKind.VoidExpression:
+                    return visitVoidExpression(node as VoidExpression);
+                case SyntaxKind.Constructor:
+                    return visitConstructorDeclaration(node as ConstructorDeclaration);
+                case SyntaxKind.MethodDeclaration:
+                    return visitMethodDeclaration(node as MethodDeclaration);
+                case SyntaxKind.GetAccessor:
+                    return visitGetAccessorDeclaration(node as GetAccessorDeclaration);
+                case SyntaxKind.SetAccessor:
+                    return visitSetAccessorDeclaration(node as SetAccessorDeclaration);
+                case SyntaxKind.FunctionDeclaration:
+                    return visitFunctionDeclaration(node as FunctionDeclaration);
+                case SyntaxKind.FunctionExpression:
+                    return visitFunctionExpression(node as FunctionExpression);
+                case SyntaxKind.ArrowFunction:
+                    return visitArrowFunction(node as ArrowFunction);
+                case SyntaxKind.Parameter:
+                    return visitParameter(node as ParameterDeclaration);
+                case SyntaxKind.ExpressionStatement:
+                    return visitExpressionStatement(node as ExpressionStatement);
+                case SyntaxKind.ParenthesizedExpression:
+                    return visitParenthesizedExpression(node as ParenthesizedExpression, noDestructuringValue);
+                default:
+                    return visitEachChild(node, visitor, context);
+            }
+        }
+
+        function chunkObjectLiteralElements(elements: ObjectLiteralElement[]): Expression[] {
+            let chunkObject: (ShorthandPropertyAssignment | PropertyAssignment)[];
+            const objects: Expression[] = [];
+            for (const e of elements) {
+                if (e.kind === SyntaxKind.SpreadAssignment) {
+                    if (chunkObject) {
+                        objects.push(createObjectLiteral(chunkObject));
+                        chunkObject = undefined;
+                    }
+                    const target = (e as SpreadAssignment).expression;
+                    objects.push(visitNode(target, visitor, isExpression));
+                }
+                else {
+                    if (!chunkObject) {
+                        chunkObject = [];
+                    }
+                    if (e.kind === SyntaxKind.PropertyAssignment) {
+                        const p = e as PropertyAssignment;
+                        chunkObject.push(createPropertyAssignment(p.name, visitNode(p.initializer, visitor, isExpression)));
+                    }
+                    else {
+                        chunkObject.push(e as ShorthandPropertyAssignment);
+                    }
+                }
+            }
+            if (chunkObject) {
+                objects.push(createObjectLiteral(chunkObject));
+            }
+
+            return objects;
+        }
+
+        function visitObjectLiteralExpression(node: ObjectLiteralExpression): Expression {
+            if (node.transformFlags & TransformFlags.ContainsObjectSpread) {
+                // spread elements emit like so:
+                // non-spread elements are chunked together into object literals, and then all are passed to __assign:
+                //     { a, ...o, b } => __assign({a}, o, {b});
+                // If the first element is a spread element, then the first argument to __assign is {}:
+                //     { ...o, a, b, ...o2 } => __assign({}, o, {a, b}, o2)
+                const objects = chunkObjectLiteralElements(node.properties);
+                if (objects.length && objects[0].kind !== SyntaxKind.ObjectLiteralExpression) {
+                    objects.unshift(createObjectLiteral());
+                }
+                return createAssignHelper(context, objects);
+            }
+            return visitEachChild(node, visitor, context);
+        }
+
+        function visitExpressionStatement(node: ExpressionStatement): ExpressionStatement {
+            return visitEachChild(node, visitorNoDestructuringValue, context);
+        }
+
+        function visitParenthesizedExpression(node: ParenthesizedExpression, noDestructuringValue: boolean): ParenthesizedExpression {
+            return visitEachChild(node, noDestructuringValue ? visitorNoDestructuringValue : visitor, context);
+        }
+
+        /**
+         * Visits a BinaryExpression that contains a destructuring assignment.
+         *
+         * @param node A BinaryExpression node.
+         */
+        function visitBinaryExpression(node: BinaryExpression, noDestructuringValue: boolean): Expression {
+            if (isDestructuringAssignment(node) && node.left.transformFlags & TransformFlags.ContainsObjectRest) {
+                return flattenDestructuringAssignment(
+                    node,
+                    visitor,
+                    context,
+                    FlattenLevel.ObjectRest,
+                    !noDestructuringValue
+                );
+            }
+            else if (node.operatorToken.kind === SyntaxKind.CommaToken) {
+                return updateBinary(
+                    node,
+                    visitNode(node.left, visitorNoDestructuringValue, isExpression),
+                    visitNode(node.right, noDestructuringValue ? visitorNoDestructuringValue : visitor, isExpression)
+                );
+            }
+            return visitEachChild(node, visitor, context);
+        }
+
+        /**
+         * Visits a VariableDeclaration node with a binding pattern.
+         *
+         * @param node A VariableDeclaration node.
+         */
+        function visitVariableDeclaration(node: VariableDeclaration): VisitResult<VariableDeclaration> {
+            // If we are here it is because the name contains a binding pattern with a rest somewhere in it.
+            if (isBindingPattern(node.name) && node.name.transformFlags & TransformFlags.ContainsObjectRest) {
+                return flattenDestructuringBinding(
+                    node,
+                    visitor,
+                    context,
+                    FlattenLevel.ObjectRest
+                );
+            }
+            return visitEachChild(node, visitor, context);
+        }
+
+        function visitForStatement(node: ForStatement): VisitResult<Statement> {
+            return updateFor(
+                node,
+                visitNode(node.initializer, visitorNoDestructuringValue, isForInitializer),
+                visitNode(node.condition, visitor, isExpression),
+                visitNode(node.incrementor, visitor, isExpression),
+                visitNode(node.statement, visitor, isStatement)
+            );
+        }
+
+        function visitVoidExpression(node: VoidExpression) {
+            return visitEachChild(node, visitorNoDestructuringValue, context);
+        }
+
+        /**
+         * Visits a ForOfStatement and converts it into a ES2015-compatible ForOfStatement.
+         *
+         * @param node A ForOfStatement.
+         */
+        function visitForOfStatement(node: ForOfStatement): VisitResult<Statement> {
+            let leadingStatements: Statement[];
+            let temp: Identifier;
+            const initializer = skipParentheses(node.initializer);
+            if (initializer.transformFlags & TransformFlags.ContainsObjectRest) {
+                if (isVariableDeclarationList(initializer)) {
+                    temp = createTempVariable(/*recordTempVariable*/ undefined);
+                    const firstDeclaration = firstOrUndefined(initializer.declarations);
+                    const declarations = flattenDestructuringBinding(
+                        firstDeclaration,
+                        visitor,
+                        context,
+                        FlattenLevel.ObjectRest,
+                        temp,
+                        /*doNotRecordTempVariablesInLine*/ false,
+                        /*skipInitializer*/ true,
+                    );
+                    if (some(declarations)) {
+                        const statement = createVariableStatement(
+                            /*modifiers*/ undefined,
+                            updateVariableDeclarationList(initializer, declarations),
+                            /*location*/ initializer
+                        );
+                        leadingStatements = append(leadingStatements, statement);
+                    }
+                }
+                else if (isAssignmentPattern(initializer)) {
+                    temp = createTempVariable(/*recordTempVariable*/ undefined);
+                    const expression = flattenDestructuringAssignment(
+                        aggregateTransformFlags(createAssignment(initializer, temp, /*location*/ node.initializer)),
+                        visitor,
+                        context,
+                        FlattenLevel.ObjectRest
+                    );
+                    leadingStatements = append(leadingStatements, createStatement(expression, /*location*/ node.initializer));
+                }
+            }
+            if (temp) {
+                const expression = visitNode(node.expression, visitor, isExpression);
+                const statement = visitNode(node.statement, visitor, isStatement);
+                const block = isBlock(statement)
+                    ? updateBlock(statement, createNodeArray(concatenate(leadingStatements, statement.statements), statement.statements))
+                    : createBlock(append(leadingStatements, statement), statement, /*multiLine*/ true);
+                return updateForOf(
+                    node,
+                    createVariableDeclarationList(
+                        [
+                            createVariableDeclaration(temp, /*type*/ undefined, /*initializer*/ undefined, node.initializer)
+                        ],
+                        node.initializer,
+                        NodeFlags.Let
+                    ),
+                    expression,
+                    block
+                );
+            }
+            return visitEachChild(node, visitor, context);
+        }
+
+        function visitParameter(node: ParameterDeclaration): ParameterDeclaration {
+            if (node.transformFlags & TransformFlags.ContainsObjectRest) {
+                // Binding patterns are converted into a generated name and are
+                // evaluated inside the function body.
+                return updateParameter(
+                    node,
+                    /*decorators*/ undefined,
+                    /*modifiers*/ undefined,
+                    node.dotDotDotToken,
+                    getGeneratedNameForNode(node),
+                    /*type*/ undefined,
+                    visitNode(node.initializer, visitor, isExpression)
+                );
+            }
+            return visitEachChild(node, visitor, context);
+        }
+
+        function visitConstructorDeclaration(node: ConstructorDeclaration) {
+            return updateConstructor(
+                node,
+                /*decorators*/ undefined,
+                node.modifiers,
+                visitParameterList(node.parameters, visitor, context),
+                transformFunctionBody(node)
+            );
+        }
+
+        function visitGetAccessorDeclaration(node: GetAccessorDeclaration) {
+            return updateGetAccessor(
+                node,
+                /*decorators*/ undefined,
+                node.modifiers,
+                visitNode(node.name, visitor, isPropertyName),
+                visitParameterList(node.parameters, visitor, context),
+                /*type*/ undefined,
+                transformFunctionBody(node)
+            );
+        }
+
+        function visitSetAccessorDeclaration(node: SetAccessorDeclaration) {
+            return updateSetAccessor(
+                node,
+                /*decorators*/ undefined,
+                node.modifiers,
+                visitNode(node.name, visitor, isPropertyName),
+                visitParameterList(node.parameters, visitor, context),
+                transformFunctionBody(node)
+            );
+        }
+
+        function visitMethodDeclaration(node: MethodDeclaration) {
+            return updateMethod(
+                node,
+                /*decorators*/ undefined,
+                node.modifiers,
+                visitNode(node.name, visitor, isPropertyName),
+                /*typeParameters*/ undefined,
+                visitParameterList(node.parameters, visitor, context),
+                /*type*/ undefined,
+                transformFunctionBody(node)
+            );
+        }
+
+        function visitFunctionDeclaration(node: FunctionDeclaration) {
+            return updateFunctionDeclaration(
+                node,
+                /*decorators*/ undefined,
+                node.modifiers,
+                node.name,
+                /*typeParameters*/ undefined,
+                visitParameterList(node.parameters, visitor, context),
+                /*type*/ undefined,
+                transformFunctionBody(node)
+            );
+        }
+
+        function visitArrowFunction(node: ArrowFunction) {
+            return updateArrowFunction(
+                node,
+                node.modifiers,
+                /*typeParameters*/ undefined,
+                visitParameterList(node.parameters, visitor, context),
+                /*type*/ undefined,
+                transformFunctionBody(node)
+            );
+        }
+
+        function visitFunctionExpression(node: FunctionExpression) {
+            return updateFunctionExpression(
+                node,
+                node.modifiers,
+                node.name,
+                /*typeParameters*/ undefined,
+                visitParameterList(node.parameters, visitor, context),
+                /*type*/ undefined,
+                transformFunctionBody(node)
+            );
+        }
+
+        function transformFunctionBody(node: FunctionDeclaration | FunctionExpression | ConstructorDeclaration | MethodDeclaration | AccessorDeclaration): FunctionBody;
+        function transformFunctionBody(node: ArrowFunction): ConciseBody;
+        function transformFunctionBody(node: FunctionLikeDeclaration): ConciseBody {
+            resumeLexicalEnvironment();
+            let leadingStatements: Statement[];
+            for (const parameter of node.parameters) {
+                if (parameter.transformFlags & TransformFlags.ContainsObjectRest) {
+                    const temp = getGeneratedNameForNode(parameter);
+                    const declarations = flattenDestructuringBinding(
+                        parameter,
+                        visitor,
+                        context,
+                        FlattenLevel.ObjectRest,
+                        temp,
+                        /*doNotRecordTempVariablesInLine*/ false,
+                        /*skipInitializer*/ true,
+                    );
+                    if (some(declarations)) {
+                        const statement = createVariableStatement(
+                            /*modifiers*/ undefined,
+                            createVariableDeclarationList(
+                                declarations
+                            )
+                        );
+                        setEmitFlags(statement, EmitFlags.CustomPrologue);
+                        leadingStatements = append(leadingStatements, statement);
+                    }
+                }
+            }
+            const body = visitNode(node.body, visitor, isConciseBody);
+            const trailingStatements = endLexicalEnvironment();
+            if (some(leadingStatements) || some(trailingStatements)) {
+                const block = convertToFunctionBody(body, /*multiLine*/ true);
+                return updateBlock(block, createNodeArray(concatenate(concatenate(leadingStatements, block.statements), trailingStatements), block.statements));
+            }
+            return body;
+        }
+    }
+
+    const assignHelper: EmitHelper = {
+        name: "typescript:assign",
+        scoped: false,
+        priority: 1,
+        text: `
+            var __assign = (this && this.__assign) || Object.assign || function(t) {
+                for (var s, i = 1, n = arguments.length; i < n; i++) {
+                    s = arguments[i];
+                    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+                        t[p] = s[p];
+                }
+                return t;
+            };`
+    };
+
+    export function createAssignHelper(context: TransformationContext, attributesSegments: Expression[]) {
+        context.requestEmitHelper(assignHelper);
+        return createCall(
+            getHelperName("__assign"),
+            /*typeArguments*/ undefined,
+            attributesSegments
+        );
+    }
+}

src/compiler/transformers/generators.ts

@@ -227,7 +227,7 @@ namespace ts {
 
     export function transformGenerators(context: TransformationContext) {
         const {
-            startLexicalEnvironment,
+            resumeLexicalEnvironment,
             endLexicalEnvironment,
             hoistFunctionDeclaration,
             hoistVariableDeclaration,
@@ -291,17 +291,18 @@ namespace ts {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (isDeclarationFile(node)
+                || (node.transformFlags & TransformFlags.ContainsGenerator) === 0) {
                 return node;
             }
 
-            if (node.transformFlags & TransformFlags.ContainsGenerator) {
-                currentSourceFile = node;
-                node = visitEachChild(node, visitor, context);
-                currentSourceFile = undefined;
-            }
+            currentSourceFile = node;
 
-            return node;
+            const visited = visitEachChild(node, visitor, context);
+            addEmitHelpers(visited, context.readEmitHelpers());
+
+            currentSourceFile = undefined;
+            return visited;
         }
 
         /**
@@ -449,11 +450,11 @@ namespace ts {
                 node = setOriginalNode(
                     createFunctionDeclaration(
                         /*decorators*/ undefined,
-                        /*modifiers*/ undefined,
+                        node.modifiers,
                         /*asteriskToken*/ undefined,
                         node.name,
                         /*typeParameters*/ undefined,
-                        node.parameters,
+                        visitParameterList(node.parameters, visitor, context),
                         /*type*/ undefined,
                         transformGeneratorFunctionBody(node.body),
                         /*location*/ node
@@ -500,7 +501,7 @@ namespace ts {
                         /*asteriskToken*/ undefined,
                         node.name,
                         /*typeParameters*/ undefined,
-                        node.parameters,
+                        visitParameterList(node.parameters, visitor, context),
                         /*type*/ undefined,
                         transformGeneratorFunctionBody(node.body),
                         /*location*/ node
@@ -578,7 +579,7 @@ namespace ts {
             state = createTempVariable(/*recordTempVariable*/ undefined);
 
             // Build the generator
-            startLexicalEnvironment();
+            resumeLexicalEnvironment();
 
             const statementOffset = addPrologueDirectives(statements, body.statements, /*ensureUseStrict*/ false, visitor);
 
@@ -937,7 +938,7 @@ namespace ts {
             }
 
             markLabel(resumeLabel);
-            return createGeneratorResume();
+            return createGeneratorResume(/*location*/ node);
         }
 
         /**
@@ -946,7 +947,7 @@ namespace ts {
          * @param node The node to visit.
          */
         function visitArrayLiteralExpression(node: ArrayLiteralExpression) {
-            return visitElements(node.elements, node.multiLine);
+            return visitElements(node.elements, /*leadingElement*/ undefined, /*location*/ undefined, node.multiLine);
         }
 
         /**
@@ -956,7 +957,7 @@ namespace ts {
          * @param elements The elements to visit.
          * @param multiLine Whether array literals created should be emitted on multiple lines.
          */
-        function visitElements(elements: NodeArray<Expression>, _multiLine?: boolean) {
+        function visitElements(elements: NodeArray<Expression>, leadingElement?: Expression, location?: TextRange, multiLine?: boolean) {
             // [source]
             //      ar = [1, yield, 2];
             //
@@ -971,18 +972,22 @@ namespace ts {
             const temp = declareLocal();
             let hasAssignedTemp = false;
             if (numInitialElements > 0) {
+                const initialElements = visitNodes(elements, visitor, isExpression, 0, numInitialElements);
                 emitAssignment(temp,
                     createArrayLiteral(
-                        visitNodes(elements, visitor, isExpression, 0, numInitialElements)
+                        leadingElement
+                            ? [leadingElement, ...initialElements]
+                            : initialElements
                     )
                 );
+                leadingElement = undefined;
                 hasAssignedTemp = true;
             }
 
             const expressions = reduceLeft(elements, reduceElement, <Expression[]>[], numInitialElements);
             return hasAssignedTemp
-                ? createArrayConcat(temp, [createArrayLiteral(expressions)])
-                : createArrayLiteral(expressions);
+                ? createArrayConcat(temp, [createArrayLiteral(expressions, /*location*/ undefined, multiLine)])
+                : createArrayLiteral(leadingElement ? [leadingElement, ...expressions] : expressions, location, multiLine);
 
             function reduceElement(expressions: Expression[], element: Expression) {
                 if (containsYield(element) && expressions.length > 0) {
@@ -991,11 +996,16 @@ namespace ts {
                         hasAssignedTemp
                             ? createArrayConcat(
                                 temp,
-                                [createArrayLiteral(expressions)]
+                                [createArrayLiteral(expressions, /*location*/ undefined, multiLine)]
+                            )
+                            : createArrayLiteral(
+                                leadingElement ? [leadingElement, ...expressions] : expressions,
+                                /*location*/ undefined,
+                                multiLine
                             )
-                            : createArrayLiteral(expressions)
                     );
                     hasAssignedTemp = true;
+                    leadingElement = undefined;
                     expressions = [];
                 }
 
@@ -1131,7 +1141,10 @@ namespace ts {
                         createFunctionApply(
                             cacheExpression(visitNode(target, visitor, isExpression)),
                             thisArg,
-                            visitElements(node.arguments)
+                            visitElements(
+                                node.arguments,
+                                /*leadingElement*/ createVoidZero()
+                            )
                         ),
                         /*typeArguments*/ undefined,
                         [],
@@ -1221,7 +1234,9 @@ namespace ts {
 
         function transformAndEmitVariableDeclarationList(node: VariableDeclarationList): VariableDeclarationList {
             for (const variable of node.declarations) {
-                hoistVariableDeclaration(<Identifier>variable.name);
+                const name = getSynthesizedClone(<Identifier>variable.name);
+                setCommentRange(name, variable.name);
+                hoistVariableDeclaration(name);
             }
 
             const variables = getInitializedVariables(node);
@@ -1274,7 +1289,7 @@ namespace ts {
                 if (containsYield(node.thenStatement) || containsYield(node.elseStatement)) {
                     const endLabel = defineLabel();
                     const elseLabel = node.elseStatement ? defineLabel() : undefined;
-                    emitBreakWhenFalse(node.elseStatement ? elseLabel : endLabel, visitNode(node.expression, visitor, isExpression));
+                    emitBreakWhenFalse(node.elseStatement ? elseLabel : endLabel, visitNode(node.expression, visitor, isExpression), /*location*/ node.expression);
                     transformAndEmitEmbeddedStatement(node.thenStatement);
                     if (node.elseStatement) {
                         emitBreak(endLabel);
@@ -2585,28 +2600,24 @@ namespace ts {
             withBlockStack = undefined;
 
             const buildResult = buildStatements();
-            return createCall(
-                createHelperName(currentSourceFile.externalHelpersModuleName, "__generator"),
-                /*typeArguments*/ undefined,
-                [
-                    createThis(),
-                    setEmitFlags(
-                        createFunctionExpression(
-                            /*modifiers*/ undefined,
-                            /*asteriskToken*/ undefined,
-                            /*name*/ undefined,
-                            /*typeParameters*/ undefined,
-                            [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, state)],
-                            /*type*/ undefined,
-                            createBlock(
-                                buildResult,
-                                /*location*/ undefined,
-                                /*multiLine*/ buildResult.length > 0
-                            )
-                        ),
-                        EmitFlags.ReuseTempVariableScope
-                    )
-                ]
+            return createGeneratorHelper(
+                context,
+                setEmitFlags(
+                    createFunctionExpression(
+                        /*modifiers*/ undefined,
+                        /*asteriskToken*/ undefined,
+                        /*name*/ undefined,
+                        /*typeParameters*/ undefined,
+                        [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, state)],
+                        /*type*/ undefined,
+                        createBlock(
+                            buildResult,
+                            /*location*/ undefined,
+                            /*multiLine*/ buildResult.length > 0
+                        )
+                    ),
+                    EmitFlags.ReuseTempVariableScope
+                )
             );
         }
 
@@ -2956,12 +2967,15 @@ namespace ts {
             lastOperationWasAbrupt = true;
             lastOperationWasCompletion = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral(expression
-                        ? [createInstruction(Instruction.Return), expression]
-                        : [createInstruction(Instruction.Return)]
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral(expression
+                            ? [createInstruction(Instruction.Return), expression]
+                            : [createInstruction(Instruction.Return)]
+                        ),
+                        operationLocation
                     ),
-                    operationLocation
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }
@@ -2975,12 +2989,15 @@ namespace ts {
         function writeBreak(label: Label, operationLocation: TextRange): void {
             lastOperationWasAbrupt = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral([
-                        createInstruction(Instruction.Break),
-                        createLabel(label)
-                    ]),
-                    operationLocation
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral([
+                            createInstruction(Instruction.Break),
+                            createLabel(label)
+                        ]),
+                        operationLocation
+                    ),
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }
@@ -2994,15 +3011,21 @@ namespace ts {
          */
         function writeBreakWhenTrue(label: Label, condition: Expression, operationLocation: TextRange): void {
             writeStatement(
-                createIf(
-                    condition,
-                    createReturn(
-                        createArrayLiteral([
-                            createInstruction(Instruction.Break),
-                            createLabel(label)
-                        ]),
-                        operationLocation
-                    )
+                setEmitFlags(
+                    createIf(
+                        condition,
+                        setEmitFlags(
+                            createReturn(
+                                createArrayLiteral([
+                                    createInstruction(Instruction.Break),
+                                    createLabel(label)
+                                ]),
+                                operationLocation
+                            ),
+                            EmitFlags.NoTokenSourceMaps
+                        )
+                    ),
+                    EmitFlags.SingleLine
                 )
             );
         }
@@ -3016,15 +3039,21 @@ namespace ts {
          */
         function writeBreakWhenFalse(label: Label, condition: Expression, operationLocation: TextRange): void {
             writeStatement(
-                createIf(
-                    createLogicalNot(condition),
-                    createReturn(
-                        createArrayLiteral([
-                            createInstruction(Instruction.Break),
-                            createLabel(label)
-                        ]),
-                        operationLocation
-                    )
+                setEmitFlags(
+                    createIf(
+                        createLogicalNot(condition),
+                        setEmitFlags(
+                            createReturn(
+                                createArrayLiteral([
+                                    createInstruction(Instruction.Break),
+                                    createLabel(label)
+                                ]),
+                                operationLocation
+                            ),
+                            EmitFlags.NoTokenSourceMaps
+                        )
+                    ),
+                    EmitFlags.SingleLine
                 )
             );
         }
@@ -3038,13 +3067,16 @@ namespace ts {
         function writeYield(expression: Expression, operationLocation: TextRange): void {
             lastOperationWasAbrupt = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral(
-                        expression
-                            ? [createInstruction(Instruction.Yield), expression]
-                            : [createInstruction(Instruction.Yield)]
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral(
+                            expression
+                                ? [createInstruction(Instruction.Yield), expression]
+                                : [createInstruction(Instruction.Yield)]
+                        ),
+                        operationLocation
                     ),
-                    operationLocation
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }
@@ -3058,12 +3090,15 @@ namespace ts {
         function writeYieldStar(expression: Expression, operationLocation: TextRange): void {
             lastOperationWasAbrupt = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral([
-                        createInstruction(Instruction.YieldStar),
-                        expression
-                    ]),
-                    operationLocation
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral([
+                            createInstruction(Instruction.YieldStar),
+                            expression
+                        ]),
+                        operationLocation
+                    ),
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }
@@ -3082,4 +3117,105 @@ namespace ts {
             );
         }
     }
+
+    function createGeneratorHelper(context: TransformationContext, body: FunctionExpression) {
+        context.requestEmitHelper(generatorHelper);
+        return createCall(
+            getHelperName("__generator"),
+            /*typeArguments*/ undefined,
+            [createThis(), body]);
+    }
+
+    // The __generator helper is used by down-level transformations to emulate the runtime
+    // semantics of an ES2015 generator function. When called, this helper returns an
+    // object that implements the Iterator protocol, in that it has `next`, `return`, and
+    // `throw` methods that step through the generator when invoked.
+    //
+    // parameters:
+    //  thisArg  The value to use as the `this` binding for the transformed generator body.
+    //  body     A function that acts as the transformed generator body.
+    //
+    // variables:
+    //  _       Persistent state for the generator that is shared between the helper and the
+    //          generator body. The state object has the following members:
+    //            sent() - A method that returns or throws the current completion value.
+    //            label  - The next point at which to resume evaluation of the generator body.
+    //            trys   - A stack of protected regions (try/catch/finally blocks).
+    //            ops    - A stack of pending instructions when inside of a finally block.
+    //  f       A value indicating whether the generator is executing.
+    //  y       An iterator to delegate for a yield*.
+    //  t       A temporary variable that holds one of the following values (note that these
+    //          cases do not overlap):
+    //          - The completion value when resuming from a `yield` or `yield*`.
+    //          - The error value for a catch block.
+    //          - The current protected region (array of try/catch/finally/end labels).
+    //          - The verb (`next`, `throw`, or `return` method) to delegate to the expression
+    //            of a `yield*`.
+    //          - The result of evaluating the verb delegated to the expression of a `yield*`.
+    //
+    // functions:
+    //  verb(n)     Creates a bound callback to the `step` function for opcode `n`.
+    //  step(op)    Evaluates opcodes in a generator body until execution is suspended or
+    //              completed.
+    //
+    // The __generator helper understands a limited set of instructions:
+    //  0: next(value?)     - Start or resume the generator with the specified value.
+    //  1: throw(error)     - Resume the generator with an exception. If the generator is
+    //                        suspended inside of one or more protected regions, evaluates
+    //                        any intervening finally blocks between the current label and
+    //                        the nearest catch block or function boundary. If uncaught, the
+    //                        exception is thrown to the caller.
+    //  2: return(value?)   - Resume the generator as if with a return. If the generator is
+    //                        suspended inside of one or more protected regions, evaluates any
+    //                        intervening finally blocks.
+    //  3: break(label)     - Jump to the specified label. If the label is outside of the
+    //                        current protected region, evaluates any intervening finally
+    //                        blocks.
+    //  4: yield(value?)    - Yield execution to the caller with an optional value. When
+    //                        resumed, the generator will continue at the next label.
+    //  5: yield*(value)    - Delegates evaluation to the supplied iterator. When
+    //                        delegation completes, the generator will continue at the next
+    //                        label.
+    //  6: catch(error)     - Handles an exception thrown from within the generator body. If
+    //                        the current label is inside of one or more protected regions,
+    //                        evaluates any intervening finally blocks between the current
+    //                        label and the nearest catch block or function boundary. If
+    //                        uncaught, the exception is thrown to the caller.
+    //  7: endfinally       - Ends a finally block, resuming the last instruction prior to
+    //                        entering a finally block.
+    //
+    // For examples of how these are used, see the comments in ./transformers/generators.ts
+    const generatorHelper: EmitHelper = {
+        name: "typescript:generator",
+        scoped: false,
+        priority: 6,
+        text: `
+            var __generator = (this && this.__generator) || function (thisArg, body) {
+                var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t;
+                return { next: verb(0), "throw": verb(1), "return": verb(2) };
+                function verb(n) { return function (v) { return step([n, v]); }; }
+                function step(op) {
+                    if (f) throw new TypeError("Generator is already executing.");
+                    while (_) try {
+                        if (f = 1, y && (t = y[op[0] & 2 ? "return" : op[0] ? "throw" : "next"]) && !(t = t.call(y, op[1])).done) return t;
+                        if (y = 0, t) op = [0, t.value];
+                        switch (op[0]) {
+                            case 0: case 1: t = op; break;
+                            case 4: _.label++; return { value: op[1], done: false };
+                            case 5: _.label++; y = op[1]; op = [0]; continue;
+                            case 7: op = _.ops.pop(); _.trys.pop(); continue;
+                            default:
+                                if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
+                                if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
+                                if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
+                                if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
+                                if (t[2]) _.ops.pop();
+                                _.trys.pop(); continue;
+                        }
+                        op = body.call(thisArg, _);
+                    } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
+                    if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
+                }
+            };`
+    };
 }

src/compiler/transformers/jsx.ts

@@ -1,13 +1,13 @@
 /// <reference path="../factory.ts" />
 /// <reference path="../visitor.ts" />
+/// <reference path="./esnext.ts" />
 
 /*@internal*/
 namespace ts {
-    const entities: Map<number> = createEntitiesMap();
-
     export function transformJsx(context: TransformationContext) {
         const compilerOptions = context.getCompilerOptions();
         let currentSourceFile: SourceFile;
+
         return transformSourceFile;
 
         /**
@@ -21,18 +21,18 @@ namespace ts {
             }
 
             currentSourceFile = node;
-            node = visitEachChild(node, visitor, context);
+
+            const visited = visitEachChild(node, visitor, context);
+            addEmitHelpers(visited, context.readEmitHelpers());
+
             currentSourceFile = undefined;
-            return node;
+            return visited;
         }
 
         function visitor(node: Node): VisitResult<Node> {
-            if (node.transformFlags & TransformFlags.Jsx) {
+            if (node.transformFlags & TransformFlags.ContainsJsx) {
                 return visitorWorker(node);
             }
-            else if (node.transformFlags & TransformFlags.ContainsJsx) {
-                return visitEachChild(node, visitor, context);
-            }
             else {
                 return node;
             }
@@ -50,8 +50,7 @@ namespace ts {
                     return visitJsxExpression(<JsxExpression>node);
 
                 default:
-                    Debug.failBadSyntaxKind(node);
-                    return undefined;
+                    return visitEachChild(node, visitor, context);
             }
         }
 
@@ -109,11 +108,14 @@ namespace ts {
 
                 // Either emit one big object literal (no spread attribs), or
                 // a call to the __assign helper.
-                objectProperties = singleOrUndefined(segments)
-                    || createAssignHelper(currentSourceFile.externalHelpersModuleName, segments);
+                objectProperties = singleOrUndefined(segments);
+                if (!objectProperties) {
+                    objectProperties = createAssignHelper(context, segments);
+                }
             }
 
-            const element = createReactCreateElement(
+            const element = createExpressionForJsxElement(
+                context.getEmitResolver().getJsxFactoryEntity(),
                 compilerOptions.reactNamespace,
                 tagName,
                 objectProperties,
@@ -275,261 +277,259 @@ namespace ts {
         }
     }
 
-    function createEntitiesMap(): Map<number> {
-        return createMap<number>({
-            "quot": 0x0022,
-            "amp": 0x0026,
-            "apos": 0x0027,
-            "lt": 0x003C,
-            "gt": 0x003E,
-            "nbsp": 0x00A0,
-            "iexcl": 0x00A1,
-            "cent": 0x00A2,
-            "pound": 0x00A3,
-            "curren": 0x00A4,
-            "yen": 0x00A5,
-            "brvbar": 0x00A6,
-            "sect": 0x00A7,
-            "uml": 0x00A8,
-            "copy": 0x00A9,
-            "ordf": 0x00AA,
-            "laquo": 0x00AB,
-            "not": 0x00AC,
-            "shy": 0x00AD,
-            "reg": 0x00AE,
-            "macr": 0x00AF,
-            "deg": 0x00B0,
-            "plusmn": 0x00B1,
-            "sup2": 0x00B2,
-            "sup3": 0x00B3,
-            "acute": 0x00B4,
-            "micro": 0x00B5,
-            "para": 0x00B6,
-            "middot": 0x00B7,
-            "cedil": 0x00B8,
-            "sup1": 0x00B9,
-            "ordm": 0x00BA,
-            "raquo": 0x00BB,
-            "frac14": 0x00BC,
-            "frac12": 0x00BD,
-            "frac34": 0x00BE,
-            "iquest": 0x00BF,
-            "Agrave": 0x00C0,
-            "Aacute": 0x00C1,
-            "Acirc": 0x00C2,
-            "Atilde": 0x00C3,
-            "Auml": 0x00C4,
-            "Aring": 0x00C5,
-            "AElig": 0x00C6,
-            "Ccedil": 0x00C7,
-            "Egrave": 0x00C8,
-            "Eacute": 0x00C9,
-            "Ecirc": 0x00CA,
-            "Euml": 0x00CB,
-            "Igrave": 0x00CC,
-            "Iacute": 0x00CD,
-            "Icirc": 0x00CE,
-            "Iuml": 0x00CF,
-            "ETH": 0x00D0,
-            "Ntilde": 0x00D1,
-            "Ograve": 0x00D2,
-            "Oacute": 0x00D3,
-            "Ocirc": 0x00D4,
-            "Otilde": 0x00D5,
-            "Ouml": 0x00D6,
-            "times": 0x00D7,
-            "Oslash": 0x00D8,
-            "Ugrave": 0x00D9,
-            "Uacute": 0x00DA,
-            "Ucirc": 0x00DB,
-            "Uuml": 0x00DC,
-            "Yacute": 0x00DD,
-            "THORN": 0x00DE,
-            "szlig": 0x00DF,
-            "agrave": 0x00E0,
-            "aacute": 0x00E1,
-            "acirc": 0x00E2,
-            "atilde": 0x00E3,
-            "auml": 0x00E4,
-            "aring": 0x00E5,
-            "aelig": 0x00E6,
-            "ccedil": 0x00E7,
-            "egrave": 0x00E8,
-            "eacute": 0x00E9,
-            "ecirc": 0x00EA,
-            "euml": 0x00EB,
-            "igrave": 0x00EC,
-            "iacute": 0x00ED,
-            "icirc": 0x00EE,
-            "iuml": 0x00EF,
-            "eth": 0x00F0,
-            "ntilde": 0x00F1,
-            "ograve": 0x00F2,
-            "oacute": 0x00F3,
-            "ocirc": 0x00F4,
-            "otilde": 0x00F5,
-            "ouml": 0x00F6,
-            "divide": 0x00F7,
-            "oslash": 0x00F8,
-            "ugrave": 0x00F9,
-            "uacute": 0x00FA,
-            "ucirc": 0x00FB,
-            "uuml": 0x00FC,
-            "yacute": 0x00FD,
-            "thorn": 0x00FE,
-            "yuml": 0x00FF,
-            "OElig": 0x0152,
-            "oelig": 0x0153,
-            "Scaron": 0x0160,
-            "scaron": 0x0161,
-            "Yuml": 0x0178,
-            "fnof": 0x0192,
-            "circ": 0x02C6,
-            "tilde": 0x02DC,
-            "Alpha": 0x0391,
-            "Beta": 0x0392,
-            "Gamma": 0x0393,
-            "Delta": 0x0394,
-            "Epsilon": 0x0395,
-            "Zeta": 0x0396,
-            "Eta": 0x0397,
-            "Theta": 0x0398,
-            "Iota": 0x0399,
-            "Kappa": 0x039A,
-            "Lambda": 0x039B,
-            "Mu": 0x039C,
-            "Nu": 0x039D,
-            "Xi": 0x039E,
-            "Omicron": 0x039F,
-            "Pi": 0x03A0,
-            "Rho": 0x03A1,
-            "Sigma": 0x03A3,
-            "Tau": 0x03A4,
-            "Upsilon": 0x03A5,
-            "Phi": 0x03A6,
-            "Chi": 0x03A7,
-            "Psi": 0x03A8,
-            "Omega": 0x03A9,
-            "alpha": 0x03B1,
-            "beta": 0x03B2,
-            "gamma": 0x03B3,
-            "delta": 0x03B4,
-            "epsilon": 0x03B5,
-            "zeta": 0x03B6,
-            "eta": 0x03B7,
-            "theta": 0x03B8,
-            "iota": 0x03B9,
-            "kappa": 0x03BA,
-            "lambda": 0x03BB,
-            "mu": 0x03BC,
-            "nu": 0x03BD,
-            "xi": 0x03BE,
-            "omicron": 0x03BF,
-            "pi": 0x03C0,
-            "rho": 0x03C1,
-            "sigmaf": 0x03C2,
-            "sigma": 0x03C3,
-            "tau": 0x03C4,
-            "upsilon": 0x03C5,
-            "phi": 0x03C6,
-            "chi": 0x03C7,
-            "psi": 0x03C8,
-            "omega": 0x03C9,
-            "thetasym": 0x03D1,
-            "upsih": 0x03D2,
-            "piv": 0x03D6,
-            "ensp": 0x2002,
-            "emsp": 0x2003,
-            "thinsp": 0x2009,
-            "zwnj": 0x200C,
-            "zwj": 0x200D,
-            "lrm": 0x200E,
-            "rlm": 0x200F,
-            "ndash": 0x2013,
-            "mdash": 0x2014,
-            "lsquo": 0x2018,
-            "rsquo": 0x2019,
-            "sbquo": 0x201A,
-            "ldquo": 0x201C,
-            "rdquo": 0x201D,
-            "bdquo": 0x201E,
-            "dagger": 0x2020,
-            "Dagger": 0x2021,
-            "bull": 0x2022,
-            "hellip": 0x2026,
-            "permil": 0x2030,
-            "prime": 0x2032,
-            "Prime": 0x2033,
-            "lsaquo": 0x2039,
-            "rsaquo": 0x203A,
-            "oline": 0x203E,
-            "frasl": 0x2044,
-            "euro": 0x20AC,
-            "image": 0x2111,
-            "weierp": 0x2118,
-            "real": 0x211C,
-            "trade": 0x2122,
-            "alefsym": 0x2135,
-            "larr": 0x2190,
-            "uarr": 0x2191,
-            "rarr": 0x2192,
-            "darr": 0x2193,
-            "harr": 0x2194,
-            "crarr": 0x21B5,
-            "lArr": 0x21D0,
-            "uArr": 0x21D1,
-            "rArr": 0x21D2,
-            "dArr": 0x21D3,
-            "hArr": 0x21D4,
-            "forall": 0x2200,
-            "part": 0x2202,
-            "exist": 0x2203,
-            "empty": 0x2205,
-            "nabla": 0x2207,
-            "isin": 0x2208,
-            "notin": 0x2209,
-            "ni": 0x220B,
-            "prod": 0x220F,
-            "sum": 0x2211,
-            "minus": 0x2212,
-            "lowast": 0x2217,
-            "radic": 0x221A,
-            "prop": 0x221D,
-            "infin": 0x221E,
-            "ang": 0x2220,
-            "and": 0x2227,
-            "or": 0x2228,
-            "cap": 0x2229,
-            "cup": 0x222A,
-            "int": 0x222B,
-            "there4": 0x2234,
-            "sim": 0x223C,
-            "cong": 0x2245,
-            "asymp": 0x2248,
-            "ne": 0x2260,
-            "equiv": 0x2261,
-            "le": 0x2264,
-            "ge": 0x2265,
-            "sub": 0x2282,
-            "sup": 0x2283,
-            "nsub": 0x2284,
-            "sube": 0x2286,
-            "supe": 0x2287,
-            "oplus": 0x2295,
-            "otimes": 0x2297,
-            "perp": 0x22A5,
-            "sdot": 0x22C5,
-            "lceil": 0x2308,
-            "rceil": 0x2309,
-            "lfloor": 0x230A,
-            "rfloor": 0x230B,
-            "lang": 0x2329,
-            "rang": 0x232A,
-            "loz": 0x25CA,
-            "spades": 0x2660,
-            "clubs": 0x2663,
-            "hearts": 0x2665,
-            "diams": 0x2666
-        });
-    }
+    const entities = createMap<number>({
+        "quot": 0x0022,
+        "amp": 0x0026,
+        "apos": 0x0027,
+        "lt": 0x003C,
+        "gt": 0x003E,
+        "nbsp": 0x00A0,
+        "iexcl": 0x00A1,
+        "cent": 0x00A2,
+        "pound": 0x00A3,
+        "curren": 0x00A4,
+        "yen": 0x00A5,
+        "brvbar": 0x00A6,
+        "sect": 0x00A7,
+        "uml": 0x00A8,
+        "copy": 0x00A9,
+        "ordf": 0x00AA,
+        "laquo": 0x00AB,
+        "not": 0x00AC,
+        "shy": 0x00AD,
+        "reg": 0x00AE,
+        "macr": 0x00AF,
+        "deg": 0x00B0,
+        "plusmn": 0x00B1,
+        "sup2": 0x00B2,
+        "sup3": 0x00B3,
+        "acute": 0x00B4,
+        "micro": 0x00B5,
+        "para": 0x00B6,
+        "middot": 0x00B7,
+        "cedil": 0x00B8,
+        "sup1": 0x00B9,
+        "ordm": 0x00BA,
+        "raquo": 0x00BB,
+        "frac14": 0x00BC,
+        "frac12": 0x00BD,
+        "frac34": 0x00BE,
+        "iquest": 0x00BF,
+        "Agrave": 0x00C0,
+        "Aacute": 0x00C1,
+        "Acirc": 0x00C2,
+        "Atilde": 0x00C3,
+        "Auml": 0x00C4,
+        "Aring": 0x00C5,
+        "AElig": 0x00C6,
+        "Ccedil": 0x00C7,
+        "Egrave": 0x00C8,
+        "Eacute": 0x00C9,
+        "Ecirc": 0x00CA,
+        "Euml": 0x00CB,
+        "Igrave": 0x00CC,
+        "Iacute": 0x00CD,
+        "Icirc": 0x00CE,
+        "Iuml": 0x00CF,
+        "ETH": 0x00D0,
+        "Ntilde": 0x00D1,
+        "Ograve": 0x00D2,
+        "Oacute": 0x00D3,
+        "Ocirc": 0x00D4,
+        "Otilde": 0x00D5,
+        "Ouml": 0x00D6,
+        "times": 0x00D7,
+        "Oslash": 0x00D8,
+        "Ugrave": 0x00D9,
+        "Uacute": 0x00DA,
+        "Ucirc": 0x00DB,
+        "Uuml": 0x00DC,
+        "Yacute": 0x00DD,
+        "THORN": 0x00DE,
+        "szlig": 0x00DF,
+        "agrave": 0x00E0,
+        "aacute": 0x00E1,
+        "acirc": 0x00E2,
+        "atilde": 0x00E3,
+        "auml": 0x00E4,
+        "aring": 0x00E5,
+        "aelig": 0x00E6,
+        "ccedil": 0x00E7,
+        "egrave": 0x00E8,
+        "eacute": 0x00E9,
+        "ecirc": 0x00EA,
+        "euml": 0x00EB,
+        "igrave": 0x00EC,
+        "iacute": 0x00ED,
+        "icirc": 0x00EE,
+        "iuml": 0x00EF,
+        "eth": 0x00F0,
+        "ntilde": 0x00F1,
+        "ograve": 0x00F2,
+        "oacute": 0x00F3,
+        "ocirc": 0x00F4,
+        "otilde": 0x00F5,
+        "ouml": 0x00F6,
+        "divide": 0x00F7,
+        "oslash": 0x00F8,
+        "ugrave": 0x00F9,
+        "uacute": 0x00FA,
+        "ucirc": 0x00FB,
+        "uuml": 0x00FC,
+        "yacute": 0x00FD,
+        "thorn": 0x00FE,
+        "yuml": 0x00FF,
+        "OElig": 0x0152,
+        "oelig": 0x0153,
+        "Scaron": 0x0160,
+        "scaron": 0x0161,
+        "Yuml": 0x0178,
+        "fnof": 0x0192,
+        "circ": 0x02C6,
+        "tilde": 0x02DC,
+        "Alpha": 0x0391,
+        "Beta": 0x0392,
+        "Gamma": 0x0393,
+        "Delta": 0x0394,
+        "Epsilon": 0x0395,
+        "Zeta": 0x0396,
+        "Eta": 0x0397,
+        "Theta": 0x0398,
+        "Iota": 0x0399,
+        "Kappa": 0x039A,
+        "Lambda": 0x039B,
+        "Mu": 0x039C,
+        "Nu": 0x039D,
+        "Xi": 0x039E,
+        "Omicron": 0x039F,
+        "Pi": 0x03A0,
+        "Rho": 0x03A1,
+        "Sigma": 0x03A3,
+        "Tau": 0x03A4,
+        "Upsilon": 0x03A5,
+        "Phi": 0x03A6,
+        "Chi": 0x03A7,
+        "Psi": 0x03A8,
+        "Omega": 0x03A9,
+        "alpha": 0x03B1,
+        "beta": 0x03B2,
+        "gamma": 0x03B3,
+        "delta": 0x03B4,
+        "epsilon": 0x03B5,
+        "zeta": 0x03B6,
+        "eta": 0x03B7,
+        "theta": 0x03B8,
+        "iota": 0x03B9,
+        "kappa": 0x03BA,
+        "lambda": 0x03BB,
+        "mu": 0x03BC,
+        "nu": 0x03BD,
+        "xi": 0x03BE,
+        "omicron": 0x03BF,
+        "pi": 0x03C0,
+        "rho": 0x03C1,
+        "sigmaf": 0x03C2,
+        "sigma": 0x03C3,
+        "tau": 0x03C4,
+        "upsilon": 0x03C5,
+        "phi": 0x03C6,
+        "chi": 0x03C7,
+        "psi": 0x03C8,
+        "omega": 0x03C9,
+        "thetasym": 0x03D1,
+        "upsih": 0x03D2,
+        "piv": 0x03D6,
+        "ensp": 0x2002,
+        "emsp": 0x2003,
+        "thinsp": 0x2009,
+        "zwnj": 0x200C,
+        "zwj": 0x200D,
+        "lrm": 0x200E,
+        "rlm": 0x200F,
+        "ndash": 0x2013,
+        "mdash": 0x2014,
+        "lsquo": 0x2018,
+        "rsquo": 0x2019,
+        "sbquo": 0x201A,
+        "ldquo": 0x201C,
+        "rdquo": 0x201D,
+        "bdquo": 0x201E,
+        "dagger": 0x2020,
+        "Dagger": 0x2021,
+        "bull": 0x2022,
+        "hellip": 0x2026,
+        "permil": 0x2030,
+        "prime": 0x2032,
+        "Prime": 0x2033,
+        "lsaquo": 0x2039,
+        "rsaquo": 0x203A,
+        "oline": 0x203E,
+        "frasl": 0x2044,
+        "euro": 0x20AC,
+        "image": 0x2111,
+        "weierp": 0x2118,
+        "real": 0x211C,
+        "trade": 0x2122,
+        "alefsym": 0x2135,
+        "larr": 0x2190,
+        "uarr": 0x2191,
+        "rarr": 0x2192,
+        "darr": 0x2193,
+        "harr": 0x2194,
+        "crarr": 0x21B5,
+        "lArr": 0x21D0,
+        "uArr": 0x21D1,
+        "rArr": 0x21D2,
+        "dArr": 0x21D3,
+        "hArr": 0x21D4,
+        "forall": 0x2200,
+        "part": 0x2202,
+        "exist": 0x2203,
+        "empty": 0x2205,
+        "nabla": 0x2207,
+        "isin": 0x2208,
+        "notin": 0x2209,
+        "ni": 0x220B,
+        "prod": 0x220F,
+        "sum": 0x2211,
+        "minus": 0x2212,
+        "lowast": 0x2217,
+        "radic": 0x221A,
+        "prop": 0x221D,
+        "infin": 0x221E,
+        "ang": 0x2220,
+        "and": 0x2227,
+        "or": 0x2228,
+        "cap": 0x2229,
+        "cup": 0x222A,
+        "int": 0x222B,
+        "there4": 0x2234,
+        "sim": 0x223C,
+        "cong": 0x2245,
+        "asymp": 0x2248,
+        "ne": 0x2260,
+        "equiv": 0x2261,
+        "le": 0x2264,
+        "ge": 0x2265,
+        "sub": 0x2282,
+        "sup": 0x2283,
+        "nsub": 0x2284,
+        "sube": 0x2286,
+        "supe": 0x2287,
+        "oplus": 0x2295,
+        "otimes": 0x2297,
+        "perp": 0x22A5,
+        "sdot": 0x22C5,
+        "lceil": 0x2308,
+        "rceil": 0x2309,
+        "lfloor": 0x230A,
+        "rfloor": 0x230B,
+        "lang": 0x2329,
+        "rang": 0x232A,
+        "loz": 0x25CA,
+        "spades": 0x2660,
+        "clubs": 0x2663,
+        "hearts": 0x2665,
+        "diams": 0x2666
+    });
 }

src/compiler/transformers/module/es2015.ts

@@ -5,6 +5,14 @@
 namespace ts {
     export function transformES2015Module(context: TransformationContext) {
         const compilerOptions = context.getCompilerOptions();
+        const previousOnEmitNode = context.onEmitNode;
+        const previousOnSubstituteNode = context.onSubstituteNode;
+        context.onEmitNode = onEmitNode;
+        context.onSubstituteNode = onSubstituteNode;
+        context.enableEmitNotification(SyntaxKind.SourceFile);
+        context.enableSubstitution(SyntaxKind.Identifier);
+
+        let currentSourceFile: SourceFile;
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
@@ -13,7 +21,27 @@ namespace ts {
             }
 
             if (isExternalModule(node) || compilerOptions.isolatedModules) {
-                return visitEachChild(node, visitor, context);
+                const externalHelpersModuleName = getOrCreateExternalHelpersModuleNameIfNeeded(node, compilerOptions);
+                if (externalHelpersModuleName) {
+                    const statements: Statement[] = [];
+                    const statementOffset = addPrologueDirectives(statements, node.statements);
+                    append(statements,
+                        createImportDeclaration(
+                            /*decorators*/ undefined,
+                            /*modifiers*/ undefined,
+                            createImportClause(/*name*/ undefined, createNamespaceImport(externalHelpersModuleName)),
+                            createLiteral(externalHelpersModuleNameText)
+                        )
+                    );
+
+                    addRange(statements, visitNodes(node.statements, visitor, isStatement, statementOffset));
+                    return updateSourceFileNode(
+                        node,
+                        createNodeArray(statements, node.statements));
+                }
+                else {
+                    return visitEachChild(node, visitor, context);
+                }
             }
 
             return node;
@@ -35,5 +63,55 @@ namespace ts {
             // Elide `export=` as it is not legal with --module ES6
             return node.isExportEquals ? undefined : node;
         }
+
+        //
+        // Emit Notification
+        //
+
+        /**
+         * Hook for node emit.
+         *
+         * @param emitContext A context hint for the emitter.
+         * @param node The node to emit.
+         * @param emit A callback used to emit the node in the printer.
+         */
+        function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
+            if (isSourceFile(node)) {
+                currentSourceFile = node;
+                previousOnEmitNode(emitContext, node, emitCallback);
+                currentSourceFile = undefined;
+            }
+            else {
+                previousOnEmitNode(emitContext, node, emitCallback);
+            }
+        }
+
+        //
+        // Substitutions
+        //
+
+        /**
+         * Hooks node substitutions.
+         *
+         * @param emitContext A context hint for the emitter.
+         * @param node The node to substitute.
+         */
+        function onSubstituteNode(emitContext: EmitContext, node: Node) {
+            node = previousOnSubstituteNode(emitContext, node);
+            if (isIdentifier(node) && emitContext === EmitContext.Expression) {
+                return substituteExpressionIdentifier(node);
+            }
+            return node;
+        }
+
+        function substituteExpressionIdentifier(node: Identifier): Expression {
+            if (getEmitFlags(node) & EmitFlags.HelperName) {
+                const externalHelpersModuleName = getExternalHelpersModuleName(currentSourceFile);
+                if (externalHelpersModuleName) {
+                    return createPropertyAccess(externalHelpersModuleName, node);
+                }
+            }
+            return node;
+        }
     }
 }

src/compiler/transformers/module/module.ts

@@ -19,8 +19,7 @@ namespace ts {
 
         const {
             startLexicalEnvironment,
-            endLexicalEnvironment,
-            hoistVariableDeclaration,
+            endLexicalEnvironment
         } = context;
 
         const compilerOptions = context.getCompilerOptions();
@@ -61,7 +60,7 @@ namespace ts {
             }
 
             currentSourceFile = node;
-            currentModuleInfo = moduleInfoMap[getOriginalNodeId(node)] = collectExternalModuleInfo(node, resolver);
+            currentModuleInfo = moduleInfoMap[getOriginalNodeId(node)] = collectExternalModuleInfo(node, resolver, compilerOptions);
 
             // Perform the transformation.
             const transformModule = transformModuleDelegates[moduleKind] || transformModuleDelegates[ModuleKind.None];
@@ -82,13 +81,14 @@ namespace ts {
 
             const statements: Statement[] = [];
             const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, sourceElementVisitor);
+            append(statements, visitNode(currentModuleInfo.externalHelpersImportDeclaration, sourceElementVisitor, isStatement, /*optional*/ true));
             addRange(statements, visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset));
             addRange(statements, endLexicalEnvironment());
             addExportEqualsIfNeeded(statements, /*emitAsReturn*/ false);
 
             const updated = updateSourceFileNode(node, createNodeArray(statements, node.statements));
             if (currentModuleInfo.hasExportStarsToExportValues) {
-                setEmitFlags(updated, EmitFlags.EmitExportStar | getEmitFlags(node));
+                addEmitHelper(updated, exportStarHelper);
             }
 
             return updated;
@@ -102,29 +102,7 @@ namespace ts {
         function transformAMDModule(node: SourceFile) {
             const define = createIdentifier("define");
             const moduleName = tryGetModuleNameFromFile(node, host, compilerOptions);
-            return transformAsynchronousModule(node, define, moduleName, /*includeNonAmdDependencies*/ true);
-        }
 
-        /**
-         * Transforms a SourceFile into a UMD module.
-         *
-         * @param node The SourceFile node.
-         */
-        function transformUMDModule(node: SourceFile) {
-            const define = createIdentifier("define");
-            setEmitFlags(define, EmitFlags.UMDDefine);
-            return transformAsynchronousModule(node, define, /*moduleName*/ undefined, /*includeNonAmdDependencies*/ false);
-        }
-
-        /**
-         * Transforms a SourceFile into an AMD or UMD module.
-         *
-         * @param node The SourceFile node.
-         * @param define The expression used to define the module.
-         * @param moduleName An expression for the module name, if available.
-         * @param includeNonAmdDependencies A value indicating whether to incldue any non-AMD dependencies.
-         */
-        function transformAsynchronousModule(node: SourceFile, define: Expression, moduleName: Expression, includeNonAmdDependencies: boolean) {
             // An AMD define function has the following shape:
             //
             //     define(id?, dependencies?, factory);
@@ -146,7 +124,7 @@ namespace ts {
             //
             // we need to add modules without alias names to the end of the dependencies list
 
-            const { aliasedModuleNames, unaliasedModuleNames, importAliasNames } = collectAsynchronousDependencies(node, includeNonAmdDependencies);
+            const { aliasedModuleNames, unaliasedModuleNames, importAliasNames } = collectAsynchronousDependencies(node, /*includeNonAmdDependencies*/ true);
 
             // Create an updated SourceFile:
             //
@@ -195,6 +173,137 @@ namespace ts {
             );
         }
 
+        /**
+         * Transforms a SourceFile into a UMD module.
+         *
+         * @param node The SourceFile node.
+         */
+        function transformUMDModule(node: SourceFile) {
+            const { aliasedModuleNames, unaliasedModuleNames, importAliasNames } = collectAsynchronousDependencies(node, /*includeNonAmdDependencies*/ false);
+            const umdHeader = createFunctionExpression(
+                /*modifiers*/ undefined,
+                /*asteriskToken*/ undefined,
+                /*name*/ undefined,
+                /*typeParameters*/ undefined,
+                [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "factory")],
+                /*type*/ undefined,
+                createBlock(
+                    [
+                        createIf(
+                            createLogicalAnd(
+                                createTypeCheck(createIdentifier("module"), "object"),
+                                createTypeCheck(createPropertyAccess(createIdentifier("module"), "exports"), "object")
+                            ),
+                            createBlock([
+                                createVariableStatement(
+                                    /*modifiers*/ undefined,
+                                    [
+                                        createVariableDeclaration(
+                                            "v",
+                                            /*type*/ undefined,
+                                            createCall(
+                                                createIdentifier("factory"),
+                                                /*typeArguments*/ undefined,
+                                                [
+                                                    createIdentifier("require"),
+                                                    createIdentifier("exports")
+                                                ]
+                                            )
+                                        )
+                                    ]
+                                ),
+                                setEmitFlags(
+                                    createIf(
+                                        createStrictInequality(
+                                            createIdentifier("v"),
+                                            createIdentifier("undefined")
+                                        ),
+                                        createStatement(
+                                            createAssignment(
+                                                createPropertyAccess(createIdentifier("module"), "exports"),
+                                                createIdentifier("v")
+                                            )
+                                        )
+                                    ),
+                                    EmitFlags.SingleLine
+                                )
+                            ]),
+                            createIf(
+                                createLogicalAnd(
+                                    createTypeCheck(createIdentifier("define"), "function"),
+                                    createPropertyAccess(createIdentifier("define"), "amd")
+                                ),
+                                createBlock([
+                                    createStatement(
+                                        createCall(
+                                            createIdentifier("define"),
+                                            /*typeArguments*/ undefined,
+                                            [
+                                                createArrayLiteral([
+                                                    createLiteral("require"),
+                                                    createLiteral("exports"),
+                                                    ...aliasedModuleNames,
+                                                    ...unaliasedModuleNames
+                                                ]),
+                                                createIdentifier("factory")
+                                            ]
+                                        )
+                                    )
+                                ])
+                            )
+                        )
+                    ],
+                    /*location*/ undefined,
+                    /*multiLine*/ true
+                )
+            );
+
+            // Create an updated SourceFile:
+            //
+            //  (function (factory) {
+            //      if (typeof module === "object" && typeof module.exports === "object") {
+            //          var v = factory(require, exports);
+            //          if (v !== undefined) module.exports = v;
+            //      }
+            //      else if (typeof define === 'function' && define.amd) {
+            //          define(["require", "exports"], factory);
+            //      }
+            //  })(function ...)
+
+            return updateSourceFileNode(
+                node,
+                createNodeArray(
+                    [
+                        createStatement(
+                            createCall(
+                                umdHeader,
+                                /*typeArguments*/ undefined,
+                                [
+                                    // Add the module body function argument:
+                                    //
+                                    //     function (require, exports) ...
+                                    createFunctionExpression(
+                                        /*modifiers*/ undefined,
+                                        /*asteriskToken*/ undefined,
+                                        /*name*/ undefined,
+                                        /*typeParameters*/ undefined,
+                                        [
+                                            createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "require"),
+                                            createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "exports"),
+                                            ...importAliasNames
+                                        ],
+                                        /*type*/ undefined,
+                                        transformAsynchronousModuleBody(node)
+                                    )
+                                ]
+                            )
+                        )
+                    ],
+                    /*location*/ node.statements
+                )
+            );
+        }
+
         /**
          * Collect the additional asynchronous dependencies for the module.
          *
@@ -257,6 +366,7 @@ namespace ts {
             const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, sourceElementVisitor);
 
             // Visit each statement of the module body.
+            append(statements, visitNode(currentModuleInfo.externalHelpersImportDeclaration, sourceElementVisitor, isStatement, /*optional*/ true));
             addRange(statements, visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset));
 
             // End the lexical environment for the module body
@@ -270,7 +380,7 @@ namespace ts {
             if (currentModuleInfo.hasExportStarsToExportValues) {
                 // If we have any `export * from ...` declarations
                 // we need to inform the emitter to add the __export helper.
-                setEmitFlags(body, EmitFlags.EmitExportStar);
+                addEmitHelper(body, exportStarHelper);
             }
 
             return body;
@@ -757,9 +867,12 @@ namespace ts {
          */
         function transformInitializedVariable(node: VariableDeclaration): Expression {
             if (isBindingPattern(node.name)) {
-                return flattenVariableDestructuringToExpression(
+                return flattenDestructuringAssignment(
                     node,
-                    hoistVariableDeclaration,
+                    /*visitor*/ undefined,
+                    context,
+                    FlattenLevel.All,
+                    /*needsValue*/ false,
                     createExportExpression
                 );
             }
@@ -1186,6 +1299,14 @@ namespace ts {
          * @param node The node to substitute.
          */
         function substituteExpressionIdentifier(node: Identifier): Expression {
+            if (getEmitFlags(node) & EmitFlags.HelperName) {
+                const externalHelpersModuleName = getExternalHelpersModuleName(currentSourceFile);
+                if (externalHelpersModuleName) {
+                    return createPropertyAccess(externalHelpersModuleName, node);
+                }
+                return node;
+            }
+
             if (!isGeneratedIdentifier(node) && !isLocalName(node)) {
                 const exportContainer = resolver.getReferencedExportContainer(node, isExportName(node));
                 if (exportContainer && exportContainer.kind === SyntaxKind.SourceFile) {
@@ -1312,4 +1433,14 @@ namespace ts {
             }
         }
     }
+
+    // emit output for the __export helper function
+    const exportStarHelper: EmitHelper = {
+        name: "typescript:export-star",
+        scoped: true,
+        text: `
+            function __export(m) {
+                for (var p in m) if (!exports.hasOwnProperty(p)) exports[p] = m[p];
+            }`
+    };
 }

src/compiler/transformers/module/system.ts

@@ -73,7 +73,7 @@ namespace ts {
             // see comment to 'substitutePostfixUnaryExpression' for more details
 
             // Collect information about the external module and dependency groups.
-            moduleInfo = moduleInfoMap[id] = collectExternalModuleInfo(node, resolver);
+            moduleInfo = moduleInfoMap[id] = collectExternalModuleInfo(node, resolver, compilerOptions);
 
             // Make sure that the name of the 'exports' function does not conflict with
             // existing identifiers.
@@ -82,6 +82,7 @@ namespace ts {
 
             // Add the body of the module.
             const dependencyGroups = collectDependencyGroups(moduleInfo.externalImports);
+            const moduleBodyBlock = createSystemModuleBody(node, dependencyGroups);
             const moduleBodyFunction = createFunctionExpression(
                 /*modifiers*/ undefined,
                 /*asteriskToken*/ undefined,
@@ -92,7 +93,7 @@ namespace ts {
                     createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, contextObject)
                 ],
                 /*type*/ undefined,
-                createSystemModuleBody(node, dependencyGroups)
+                moduleBodyBlock
             );
 
             // Write the call to `System.register`
@@ -100,22 +101,25 @@ namespace ts {
             // So the helper will be emit at the correct position instead of at the top of the source-file
             const moduleName = tryGetModuleNameFromFile(node, host, compilerOptions);
             const dependencies = createArrayLiteral(map(dependencyGroups, dependencyGroup => dependencyGroup.name));
-            const updated = updateSourceFileNode(
-                node,
-                createNodeArray([
-                    createStatement(
-                        createCall(
-                            createPropertyAccess(createIdentifier("System"), "register"),
+            const updated = setEmitFlags(
+                updateSourceFileNode(
+                    node,
+                    createNodeArray([
+                        createStatement(
+                            createCall(
+                                createPropertyAccess(createIdentifier("System"), "register"),
                             /*typeArguments*/ undefined,
-                            moduleName
-                                ? [moduleName, dependencies, moduleBodyFunction]
-                                : [dependencies, moduleBodyFunction]
+                                moduleName
+                                    ? [moduleName, dependencies, moduleBodyFunction]
+                                    : [dependencies, moduleBodyFunction]
+                            )
                         )
-                    )
-                ], node.statements)
-            );
+                    ], node.statements)
+                ), EmitFlags.NoTrailingComments);
 
-            setEmitFlags(updated, getEmitFlags(node) & ~EmitFlags.EmitEmitHelpers);
+            if (!(compilerOptions.outFile || compilerOptions.out)) {
+                moveEmitHelpers(updated, moduleBodyBlock, helper => !helper.scoped);
+            }
 
             if (noSubstitution) {
                 noSubstitutionMap[id] = noSubstitution;
@@ -236,6 +240,9 @@ namespace ts {
                 )
             );
 
+            // Visit the synthetic external helpers import declaration if present
+            visitNode(moduleInfo.externalHelpersImportDeclaration, sourceElementVisitor, isStatement, /*optional*/ true);
+
             // Visit the statements of the source file, emitting any transformations into
             // the `executeStatements` array. We do this *before* we fill the `setters` array
             // as we both emit transformations as well as aggregate some data used when creating
@@ -280,9 +287,7 @@ namespace ts {
                 )
             );
 
-            const body = createBlock(statements, /*location*/ undefined, /*multiLine*/ true);
-            setEmitFlags(body, EmitFlags.EmitEmitHelpers);
-            return body;
+            return createBlock(statements, /*location*/ undefined, /*multiLine*/ true);
         }
 
         /**
@@ -394,7 +399,13 @@ namespace ts {
             if (localNames) {
                 condition = createLogicalAnd(
                     condition,
-                    createLogicalNot(createHasOwnProperty(localNames, n))
+                    createLogicalNot(
+                        createCall(
+                            createPropertyAccess(localNames, "hasOwnProperty"),
+                            /*typeArguments*/ undefined,
+                            [n]
+                        )
+                    )
                 );
             }
 
@@ -808,7 +819,14 @@ namespace ts {
         function transformInitializedVariable(node: VariableDeclaration, isExportedDeclaration: boolean): Expression {
             const createAssignment = isExportedDeclaration ? createExportedVariableAssignment : createNonExportedVariableAssignment;
             return isBindingPattern(node.name)
-                ? flattenVariableDestructuringToExpression(node, hoistVariableDeclaration, createAssignment, destructuringVisitor)
+                ? flattenDestructuringAssignment(
+                    node,
+                    destructuringVisitor,
+                    context,
+                    FlattenLevel.All,
+                    /*needsValue*/ false,
+                    createAssignment
+                )
                 : createAssignment(node.name, visitNode(node.initializer, destructuringVisitor, isExpression));
         }
 
@@ -1459,7 +1477,13 @@ namespace ts {
          */
         function visitDestructuringAssignment(node: DestructuringAssignment): VisitResult<Expression> {
             if (hasExportedReferenceInDestructuringTarget(node.left)) {
-                return flattenDestructuringAssignment(context, node, /*needsValue*/ true, hoistVariableDeclaration, destructuringVisitor);
+                return flattenDestructuringAssignment(
+                    node,
+                    destructuringVisitor,
+                    context,
+                    FlattenLevel.All,
+                    /*needsValue*/ true
+                );
             }
 
             return visitEachChild(node, destructuringVisitor, context);
@@ -1474,7 +1498,7 @@ namespace ts {
             if (isAssignmentExpression(node)) {
                 return hasExportedReferenceInDestructuringTarget(node.left);
             }
-            else if (isSpreadElementExpression(node)) {
+            else if (isSpreadExpression(node)) {
                 return hasExportedReferenceInDestructuringTarget(node.expression);
             }
             else if (isObjectLiteralExpression(node)) {
@@ -1599,6 +1623,14 @@ namespace ts {
          * @param node The node to substitute.
          */
         function substituteExpressionIdentifier(node: Identifier): Expression {
+            if (getEmitFlags(node) & EmitFlags.HelperName) {
+                const externalHelpersModuleName = getExternalHelpersModuleName(currentSourceFile);
+                if (externalHelpersModuleName) {
+                    return createPropertyAccess(externalHelpersModuleName, node);
+                }
+                return node;
+            }
+
             // When we see an identifier in an expression position that
             // points to an imported symbol, we should substitute a qualified
             // reference to the imported symbol if one is needed.

src/compiler/transformers/ts.ts

@@ -21,6 +21,7 @@ namespace ts {
     export function transformTypeScript(context: TransformationContext) {
         const {
             startLexicalEnvironment,
+            resumeLexicalEnvironment,
             endLexicalEnvironment,
             hoistVariableDeclaration,
         } = context;
@@ -48,7 +49,6 @@ namespace ts {
         let currentNamespaceContainerName: Identifier;
         let currentScope: SourceFile | Block | ModuleBlock | CaseBlock;
         let currentScopeFirstDeclarationsOfName: Map<Node>;
-        let currentExternalHelpersModuleName: Identifier;
 
         /**
          * Keeps track of whether expression substitution has been enabled for specific edge cases.
@@ -80,7 +80,13 @@ namespace ts {
                 return node;
             }
 
-            return visitNode(node, visitor, isSourceFile);
+            currentSourceFile = node;
+
+            const visited = saveStateAndInvoke(node, visitSourceFile);
+            addEmitHelpers(visited, context.readEmitHelpers());
+
+            currentSourceFile = undefined;
+            return visited;
         }
 
         /**
@@ -107,6 +113,32 @@ namespace ts {
             return visited;
         }
 
+        /**
+         * Performs actions that should always occur immediately before visiting a node.
+         *
+         * @param node The node to visit.
+         */
+        function onBeforeVisitNode(node: Node) {
+            switch (node.kind) {
+                case SyntaxKind.SourceFile:
+                case SyntaxKind.CaseBlock:
+                case SyntaxKind.ModuleBlock:
+                case SyntaxKind.Block:
+                    currentScope = <SourceFile | CaseBlock | ModuleBlock | Block>node;
+                    currentScopeFirstDeclarationsOfName = undefined;
+                    break;
+
+                case SyntaxKind.ClassDeclaration:
+                case SyntaxKind.FunctionDeclaration:
+                    if (hasModifier(node, ModifierFlags.Ambient)) {
+                        break;
+                    }
+
+                    recordEmittedDeclarationInScope(node);
+                    break;
+            }
+        }
+
         /**
          * General-purpose node visitor.
          *
@@ -122,10 +154,7 @@ namespace ts {
          * @param node The node to visit.
          */
         function visitorWorker(node: Node): VisitResult<Node> {
-            if (node.kind === SyntaxKind.SourceFile) {
-                return visitSourceFile(<SourceFile>node);
-            }
-            else if (node.transformFlags & TransformFlags.TypeScript) {
+            if (node.transformFlags & TransformFlags.TypeScript) {
                 // This node is explicitly marked as TypeScript, so we should transform the node.
                 return visitTypeScript(node);
             }
@@ -252,7 +281,6 @@ namespace ts {
             return node;
         }
 
-
         /**
          * Branching visitor, visits a TypeScript syntax node.
          *
@@ -302,6 +330,7 @@ namespace ts {
                 case SyntaxKind.ThisType:
                 case SyntaxKind.TypeOperator:
                 case SyntaxKind.IndexedAccessType:
+                case SyntaxKind.MappedType:
                 case SyntaxKind.LiteralType:
                     // TypeScript type nodes are elided.
 
@@ -316,6 +345,7 @@ namespace ts {
 
                 case SyntaxKind.PropertyDeclaration:
                     // TypeScript property declarations are elided.
+                    return undefined;
 
                 case SyntaxKind.Constructor:
                     return visitConstructor(<ConstructorDeclaration>node);
@@ -441,74 +471,11 @@ namespace ts {
             }
         }
 
-        /**
-         * Performs actions that should always occur immediately before visiting a node.
-         *
-         * @param node The node to visit.
-         */
-        function onBeforeVisitNode(node: Node) {
-            switch (node.kind) {
-                case SyntaxKind.SourceFile:
-                case SyntaxKind.CaseBlock:
-                case SyntaxKind.ModuleBlock:
-                case SyntaxKind.Block:
-                    currentScope = <SourceFile | CaseBlock | ModuleBlock | Block>node;
-                    currentScopeFirstDeclarationsOfName = undefined;
-                    break;
-
-                case SyntaxKind.ClassDeclaration:
-                case SyntaxKind.FunctionDeclaration:
-                    if (hasModifier(node, ModifierFlags.Ambient)) {
-                        break;
-                    }
-
-                    recordEmittedDeclarationInScope(node);
-                    break;
-            }
-        }
-
         function visitSourceFile(node: SourceFile) {
-            currentSourceFile = node;
-
-            // ensure "use strict" is emitted in all scenarios in alwaysStrict mode
-            if (compilerOptions.alwaysStrict) {
-                node = ensureUseStrict(node);
-            }
-
-            // If the source file requires any helpers and is an external module, and
-            // the importHelpers compiler option is enabled, emit a synthesized import
-            // statement for the helpers library.
-            if (node.flags & NodeFlags.EmitHelperFlags
-                && compilerOptions.importHelpers
-                && (isExternalModule(node) || compilerOptions.isolatedModules)) {
-                startLexicalEnvironment();
-                const statements: Statement[] = [];
-                const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ false, visitor);
-                const externalHelpersModuleName = createUniqueName(externalHelpersModuleNameText);
-                const externalHelpersModuleImport = createImportDeclaration(
-                    /*decorators*/ undefined,
-                    /*modifiers*/ undefined,
-                    createImportClause(/*name*/ undefined, createNamespaceImport(externalHelpersModuleName)),
-                    createLiteral(externalHelpersModuleNameText));
-
-                externalHelpersModuleImport.parent = node;
-                externalHelpersModuleImport.flags &= ~NodeFlags.Synthesized;
-                statements.push(externalHelpersModuleImport);
-
-                currentExternalHelpersModuleName = externalHelpersModuleName;
-                addRange(statements, visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset));
-                addRange(statements, endLexicalEnvironment());
-                currentExternalHelpersModuleName = undefined;
-
-                node = updateSourceFileNode(node, createNodeArray(statements, node.statements));
-                node.externalHelpersModuleName = externalHelpersModuleName;
-            }
-            else {
-                node = visitEachChild(node, sourceElementVisitor, context);
-            }
-
-            setEmitFlags(node, EmitFlags.EmitEmitHelpers | getEmitFlags(node));
-            return node;
+            const alwaysStrict = compilerOptions.alwaysStrict && !(isExternalModule(node) && moduleKind === ModuleKind.ES2015);
+            return updateSourceFileNode(
+                node,
+                visitLexicalEnvironment(node.statements, sourceElementVisitor, context, /*start*/ 0, alwaysStrict));
         }
 
         /**
@@ -880,9 +847,8 @@ namespace ts {
             // downlevel the '...args' portion less efficiently by naively copying the contents of 'arguments' to an array.
             // Instead, we'll avoid using a rest parameter and spread into the super call as
             // 'super(...arguments)' instead of 'super(...args)', as you can see in "transformConstructorBody".
-            return constructor
-                ? visitNodes(constructor.parameters, visitor, isParameter)
-                : <ParameterDeclaration[]>[];
+            return visitParameterList(constructor && constructor.parameters, visitor, context)
+                || <ParameterDeclaration[]>[];
         }
 
         /**
@@ -897,8 +863,7 @@ namespace ts {
             const statements: Statement[] = [];
             let indexOfFirstStatement = 0;
 
-            // The body of a constructor is a new lexical environment
-            startLexicalEnvironment();
+            resumeLexicalEnvironment();
 
             if (constructor) {
                 indexOfFirstStatement = addPrologueDirectivesAndInitialSuperCall(constructor, statements);
@@ -954,15 +919,13 @@ namespace ts {
 
             // End the lexical environment.
             addRange(statements, endLexicalEnvironment());
-            return setMultiLine(
-                createBlock(
-                    createNodeArray(
-                        statements,
-                        /*location*/ constructor ? constructor.body.statements : node.members
-                    ),
-                    /*location*/ constructor ? constructor.body : /*location*/ undefined
+            return createBlock(
+                createNodeArray(
+                    statements,
+                    /*location*/ constructor ? constructor.body.statements : node.members
                 ),
-                true
+                /*location*/ constructor ? constructor.body : /*location*/ undefined,
+                /*multiLine*/ true
             );
         }
 
@@ -1260,11 +1223,12 @@ namespace ts {
             }
 
             const { firstAccessor, secondAccessor, setAccessor } = getAllAccessorDeclarations(node.members, accessor);
-            if (accessor !== firstAccessor) {
+            const firstAccessorWithDecorators = firstAccessor.decorators ? firstAccessor : secondAccessor && secondAccessor.decorators ? secondAccessor : undefined;
+            if (!firstAccessorWithDecorators || accessor !== firstAccessorWithDecorators) {
                 return undefined;
             }
 
-            const decorators = firstAccessor.decorators || (secondAccessor && secondAccessor.decorators);
+            const decorators = firstAccessorWithDecorators.decorators;
             const parameters = getDecoratorsOfParameters(setAccessor);
             if (!decorators && !parameters) {
                 return undefined;
@@ -1313,7 +1277,7 @@ namespace ts {
          * @param node The declaration node.
          * @param allDecorators An object containing all of the decorators for the declaration.
          */
-        function transformAllDecoratorsOfDeclaration(node: Declaration, allDecorators: AllDecorators) {
+        function transformAllDecoratorsOfDeclaration(node: Declaration, container: ClassLikeDeclaration, allDecorators: AllDecorators) {
             if (!allDecorators) {
                 return undefined;
             }
@@ -1321,7 +1285,7 @@ namespace ts {
             const decoratorExpressions: Expression[] = [];
             addRange(decoratorExpressions, map(allDecorators.decorators, transformDecorator));
             addRange(decoratorExpressions, flatMap(allDecorators.parameters, transformDecoratorsOfParameter));
-            addTypeMetadata(node, decoratorExpressions);
+            addTypeMetadata(node, container, decoratorExpressions);
             return decoratorExpressions;
         }
 
@@ -1370,7 +1334,7 @@ namespace ts {
          */
         function generateClassElementDecorationExpression(node: ClassExpression | ClassDeclaration, member: ClassElement) {
             const allDecorators = getAllDecoratorsOfClassElement(node, member);
-            const decoratorExpressions = transformAllDecoratorsOfDeclaration(member, allDecorators);
+            const decoratorExpressions = transformAllDecoratorsOfDeclaration(member, node, allDecorators);
             if (!decoratorExpressions) {
                 return undefined;
             }
@@ -1391,13 +1355,13 @@ namespace ts {
             //       __metadata("design:type", Function),
             //       __metadata("design:paramtypes", [Object]),
             //       __metadata("design:returntype", void 0)
-            //   ], C.prototype, "method", undefined);
+            //   ], C.prototype, "method", null);
             //
             // The emit for an accessor is:
             //
             //   __decorate([
             //       dec
-            //   ], C.prototype, "accessor", undefined);
+            //   ], C.prototype, "accessor", null);
             //
             // The emit for a property is:
             //
@@ -1420,7 +1384,7 @@ namespace ts {
                 : undefined;
 
             const helper = createDecorateHelper(
-                currentExternalHelpersModuleName,
+                context,
                 decoratorExpressions,
                 prefix,
                 memberName,
@@ -1451,14 +1415,14 @@ namespace ts {
          */
         function generateConstructorDecorationExpression(node: ClassExpression | ClassDeclaration) {
             const allDecorators = getAllDecoratorsOfConstructor(node);
-            const decoratorExpressions = transformAllDecoratorsOfDeclaration(node, allDecorators);
+            const decoratorExpressions = transformAllDecoratorsOfDeclaration(node, node, allDecorators);
             if (!decoratorExpressions) {
                 return undefined;
             }
 
             const classAlias = classAliases && classAliases[getOriginalNodeId(node)];
             const localName = getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
-            const decorate = createDecorateHelper(currentExternalHelpersModuleName, decoratorExpressions, localName);
+            const decorate = createDecorateHelper(context, decoratorExpressions, localName);
             const expression = createAssignment(localName, classAlias ? createAssignment(classAlias, decorate) : decorate);
             setEmitFlags(expression, EmitFlags.NoComments);
             setSourceMapRange(expression, moveRangePastDecorators(node));
@@ -1486,7 +1450,7 @@ namespace ts {
                 expressions = [];
                 for (const decorator of decorators) {
                     const helper = createParamHelper(
-                        currentExternalHelpersModuleName,
+                        context,
                         transformDecorator(decorator),
                         parameterOffset,
                         /*location*/ decorator.expression);
@@ -1504,43 +1468,43 @@ namespace ts {
          * @param node The declaration node.
          * @param decoratorExpressions The destination array to which to add new decorator expressions.
          */
-        function addTypeMetadata(node: Declaration, decoratorExpressions: Expression[]) {
+        function addTypeMetadata(node: Declaration, container: ClassLikeDeclaration, decoratorExpressions: Expression[]) {
             if (USE_NEW_TYPE_METADATA_FORMAT) {
-                addNewTypeMetadata(node, decoratorExpressions);
+                addNewTypeMetadata(node, container, decoratorExpressions);
             }
             else {
-                addOldTypeMetadata(node, decoratorExpressions);
+                addOldTypeMetadata(node, container, decoratorExpressions);
             }
         }
 
-        function addOldTypeMetadata(node: Declaration, decoratorExpressions: Expression[]) {
+        function addOldTypeMetadata(node: Declaration, container: ClassLikeDeclaration, decoratorExpressions: Expression[]) {
             if (compilerOptions.emitDecoratorMetadata) {
                 if (shouldAddTypeMetadata(node)) {
-                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:type", serializeTypeOfNode(node)));
+                    decoratorExpressions.push(createMetadataHelper(context, "design:type", serializeTypeOfNode(node)));
                 }
                 if (shouldAddParamTypesMetadata(node)) {
-                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:paramtypes", serializeParameterTypesOfNode(node)));
+                    decoratorExpressions.push(createMetadataHelper(context, "design:paramtypes", serializeParameterTypesOfNode(node, container)));
                 }
                 if (shouldAddReturnTypeMetadata(node)) {
-                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:returntype", serializeReturnTypeOfNode(node)));
+                    decoratorExpressions.push(createMetadataHelper(context, "design:returntype", serializeReturnTypeOfNode(node)));
                 }
             }
         }
 
-        function addNewTypeMetadata(node: Declaration, decoratorExpressions: Expression[]) {
+        function addNewTypeMetadata(node: Declaration, container: ClassLikeDeclaration, decoratorExpressions: Expression[]) {
             if (compilerOptions.emitDecoratorMetadata) {
                 let properties: ObjectLiteralElementLike[];
                 if (shouldAddTypeMetadata(node)) {
                     (properties || (properties = [])).push(createPropertyAssignment("type", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), serializeTypeOfNode(node))));
                 }
                 if (shouldAddParamTypesMetadata(node)) {
-                    (properties || (properties = [])).push(createPropertyAssignment("paramTypes", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), serializeParameterTypesOfNode(node))));
+                    (properties || (properties = [])).push(createPropertyAssignment("paramTypes", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), serializeParameterTypesOfNode(node, container))));
                 }
                 if (shouldAddReturnTypeMetadata(node)) {
                     (properties || (properties = [])).push(createPropertyAssignment("returnType", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), serializeReturnTypeOfNode(node))));
                 }
                 if (properties) {
-                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:typeinfo", createObjectLiteral(properties, /*location*/ undefined, /*multiLine*/ true)));
+                    decoratorExpressions.push(createMetadataHelper(context, "design:typeinfo", createObjectLiteral(properties, /*location*/ undefined, /*multiLine*/ true)));
                 }
             }
         }
@@ -1579,20 +1543,27 @@ namespace ts {
          * @param node The node to test.
          */
         function shouldAddParamTypesMetadata(node: Declaration): boolean {
-            const kind = node.kind;
-            return kind === SyntaxKind.ClassDeclaration
-                || kind === SyntaxKind.ClassExpression
-                || kind === SyntaxKind.MethodDeclaration
-                || kind === SyntaxKind.GetAccessor
-                || kind === SyntaxKind.SetAccessor;
+            switch (node.kind) {
+                case SyntaxKind.ClassDeclaration:
+                case SyntaxKind.ClassExpression:
+                    return getFirstConstructorWithBody(<ClassLikeDeclaration>node) !== undefined;
+                case SyntaxKind.MethodDeclaration:
+                case SyntaxKind.GetAccessor:
+                case SyntaxKind.SetAccessor:
+                    return true;
+            }
+            return false;
         }
 
+        type SerializedEntityNameAsExpression = Identifier | BinaryExpression | PropertyAccessExpression;
+        type SerializedTypeNode = SerializedEntityNameAsExpression | VoidExpression | ConditionalExpression;
+
         /**
          * Serializes the type of a node for use with decorator type metadata.
          *
          * @param node The node that should have its type serialized.
          */
-        function serializeTypeOfNode(node: Node): Expression {
+        function serializeTypeOfNode(node: Node): SerializedTypeNode {
             switch (node.kind) {
                 case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.Parameter:
@@ -1609,30 +1580,12 @@ namespace ts {
             }
         }
 
-        /**
-         * Gets the most likely element type for a TypeNode. This is not an exhaustive test
-         * as it assumes a rest argument can only be an array type (either T[], or Array<T>).
-         *
-         * @param node The type node.
-         */
-        function getRestParameterElementType(node: TypeNode) {
-            if (node && node.kind === SyntaxKind.ArrayType) {
-                return (<ArrayTypeNode>node).elementType;
-            }
-            else if (node && node.kind === SyntaxKind.TypeReference) {
-                return singleOrUndefined((<TypeReferenceNode>node).typeArguments);
-            }
-            else {
-                return undefined;
-            }
-        }
-
         /**
          * Serializes the types of the parameters of a node for use with decorator type metadata.
          *
          * @param node The node that should have its parameter types serialized.
          */
-        function serializeParameterTypesOfNode(node: Node): Expression {
+        function serializeParameterTypesOfNode(node: Node, container: ClassLikeDeclaration): ArrayLiteralExpression {
             const valueDeclaration =
                 isClassLike(node)
                     ? getFirstConstructorWithBody(node)
@@ -1640,9 +1593,9 @@ namespace ts {
                         ? node
                         : undefined;
 
-            const expressions: Expression[] = [];
+            const expressions: SerializedTypeNode[] = [];
             if (valueDeclaration) {
-                const parameters = valueDeclaration.parameters;
+                const parameters = getParametersOfDecoratedDeclaration(valueDeclaration, container);
                 const numParameters = parameters.length;
                 for (let i = 0; i < numParameters; i++) {
                     const parameter = parameters[i];
@@ -1661,12 +1614,22 @@ namespace ts {
             return createArrayLiteral(expressions);
         }
 
+        function getParametersOfDecoratedDeclaration(node: FunctionLikeDeclaration, container: ClassLikeDeclaration) {
+            if (container && node.kind === SyntaxKind.GetAccessor) {
+                const { setAccessor } = getAllAccessorDeclarations(container.members, <AccessorDeclaration>node);
+                if (setAccessor) {
+                    return setAccessor.parameters;
+                }
+            }
+            return node.parameters;
+        }
+
         /**
          * Serializes the return type of a node for use with decorator type metadata.
          *
          * @param node The node that should have its return type serialized.
          */
-        function serializeReturnTypeOfNode(node: Node): Expression {
+        function serializeReturnTypeOfNode(node: Node): SerializedTypeNode {
             if (isFunctionLike(node) && node.type) {
                 return serializeTypeNode(node.type);
             }
@@ -1695,13 +1658,16 @@ namespace ts {
          *
          * @param node The type node to serialize.
          */
-        function serializeTypeNode(node: TypeNode): Expression {
+        function serializeTypeNode(node: TypeNode): SerializedTypeNode {
             if (node === undefined) {
                 return createIdentifier("Object");
             }
 
             switch (node.kind) {
                 case SyntaxKind.VoidKeyword:
+                case SyntaxKind.UndefinedKeyword:
+                case SyntaxKind.NullKeyword:
+                case SyntaxKind.NeverKeyword:
                     return createVoidZero();
 
                 case SyntaxKind.ParenthesizedType:
@@ -1753,40 +1719,12 @@ namespace ts {
 
                 case SyntaxKind.IntersectionType:
                 case SyntaxKind.UnionType:
-                    {
-                        const unionOrIntersection = <UnionOrIntersectionTypeNode>node;
-                        let serializedUnion: Identifier;
-                        for (const typeNode of unionOrIntersection.types) {
-                            const serializedIndividual = serializeTypeNode(typeNode) as Identifier;
-                            // Non identifier
-                            if (serializedIndividual.kind !== SyntaxKind.Identifier) {
-                                serializedUnion = undefined;
-                                break;
-                            }
+                    return serializeUnionOrIntersectionType(<UnionOrIntersectionTypeNode>node);
 
-                            // One of the individual is global object, return immediately
-                            if (serializedIndividual.text === "Object") {
-                                return serializedIndividual;
-                            }
-
-                            // Different types
-                            if (serializedUnion && serializedUnion.text !== serializedIndividual.text) {
-                                serializedUnion = undefined;
-                                break;
-                            }
-
-                            serializedUnion = serializedIndividual;
-                        }
-
-                        // If we were able to find common type
-                        if (serializedUnion) {
-                            return serializedUnion;
-                        }
-                    }
-                    // Fallthrough
                 case SyntaxKind.TypeQuery:
                 case SyntaxKind.TypeOperator:
                 case SyntaxKind.IndexedAccessType:
+                case SyntaxKind.MappedType:
                 case SyntaxKind.TypeLiteral:
                 case SyntaxKind.AnyKeyword:
                 case SyntaxKind.ThisType:
@@ -1800,25 +1738,55 @@ namespace ts {
             return createIdentifier("Object");
         }
 
+        function serializeUnionOrIntersectionType(node: UnionOrIntersectionTypeNode): SerializedTypeNode {
+            let serializedUnion: SerializedTypeNode;
+            for (const typeNode of node.types) {
+                const serializedIndividual = serializeTypeNode(typeNode);
+
+                if (isVoidExpression(serializedIndividual)) {
+                    // If we dont have any other type already set, set the initial type
+                    if (!serializedUnion) {
+                        serializedUnion = serializedIndividual;
+                    }
+                }
+                else if (isIdentifier(serializedIndividual) && serializedIndividual.text === "Object") {
+                    // One of the individual is global object, return immediately
+                    return serializedIndividual;
+                }
+                // If there exists union that is not void 0 expression, check if the the common type is identifier.
+                // anything more complex and we will just default to Object
+                else if (serializedUnion && !isVoidExpression(serializedUnion)) {
+                    // Different types
+                    if (!isIdentifier(serializedUnion) ||
+                        !isIdentifier(serializedIndividual) ||
+                        serializedUnion.text !== serializedIndividual.text) {
+                        return createIdentifier("Object");
+                    }
+                }
+                else {
+                    // Initialize the union type
+                    serializedUnion = serializedIndividual;
+                }
+            }
+
+            // If we were able to find common type, use it
+            return serializedUnion;
+        }
+
         /**
          * Serializes a TypeReferenceNode to an appropriate JS constructor value for use with
          * decorator type metadata.
          *
          * @param node The type reference node.
          */
-        function serializeTypeReferenceNode(node: TypeReferenceNode) {
+        function serializeTypeReferenceNode(node: TypeReferenceNode): SerializedTypeNode {
             switch (resolver.getTypeReferenceSerializationKind(node.typeName, currentScope)) {
                 case TypeReferenceSerializationKind.Unknown:
                     const serialized = serializeEntityNameAsExpression(node.typeName, /*useFallback*/ true);
                     const temp = createTempVariable(hoistVariableDeclaration);
                     return createLogicalOr(
                         createLogicalAnd(
-                            createStrictEquality(
-                                createTypeOf(
-                                    createAssignment(temp, serialized)
-                                ),
-                                createLiteral("function")
-                            ),
+                            createTypeCheck(createAssignment(temp, serialized), "function"),
                             temp
                         ),
                         createIdentifier("Object")
@@ -1866,7 +1834,7 @@ namespace ts {
          * @param useFallback A value indicating whether to use logical operators to test for the
          *                    entity name at runtime.
          */
-        function serializeEntityNameAsExpression(node: EntityName, useFallback: boolean): Expression {
+        function serializeEntityNameAsExpression(node: EntityName, useFallback: boolean): SerializedEntityNameAsExpression {
             switch (node.kind) {
                 case SyntaxKind.Identifier:
                     // Create a clone of the name with a new parent, and treat it as if it were
@@ -1899,8 +1867,8 @@ namespace ts {
          * @param useFallback A value indicating whether to use logical operators to test for the
          *                    qualified name at runtime.
          */
-        function serializeQualifiedNameAsExpression(node: QualifiedName, useFallback: boolean): Expression {
-            let left: Expression;
+        function serializeQualifiedNameAsExpression(node: QualifiedName, useFallback: boolean): PropertyAccessExpression {
+            let left: SerializedEntityNameAsExpression;
             if (node.left.kind === SyntaxKind.Identifier) {
                 left = serializeEntityNameAsExpression(node.left, useFallback);
             }
@@ -1925,15 +1893,10 @@ namespace ts {
          * Gets an expression that points to the global "Symbol" constructor at runtime if it is
          * available.
          */
-        function getGlobalSymbolNameWithFallback(): Expression {
+        function getGlobalSymbolNameWithFallback(): ConditionalExpression {
             return createConditional(
-                createStrictEquality(
-                    createTypeOf(createIdentifier("Symbol")),
-                    createLiteral("function")
-                ),
-                createToken(SyntaxKind.QuestionToken),
+                createTypeCheck(createIdentifier("Symbol"), "function"),
                 createIdentifier("Symbol"),
-                createToken(SyntaxKind.ColonToken),
                 createIdentifier("Object")
             );
         }
@@ -1952,7 +1915,7 @@ namespace ts {
                     : (<ComputedPropertyName>name).expression;
             }
             else if (isIdentifier(name)) {
-                return createLiteral(name.text);
+                return createLiteral(unescapeIdentifier(name.text));
             }
             else {
                 return getSynthesizedClone(name);
@@ -2057,26 +2020,23 @@ namespace ts {
             if (!shouldEmitFunctionLikeDeclaration(node)) {
                 return undefined;
             }
-
-            const method = createMethod(
+            const updated = updateMethod(
+                node,
                 /*decorators*/ undefined,
                 visitNodes(node.modifiers, modifierVisitor, isModifier),
-                node.asteriskToken,
                 visitPropertyNameOfClassElement(node),
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                transformFunctionBody(node),
-                /*location*/ node
+                visitFunctionBody(node.body, visitor, context)
             );
-
-            // While we emit the source map for the node after skipping decorators and modifiers,
-            // we need to emit the comments for the original range.
-            setCommentRange(method, node);
-            setSourceMapRange(method, moveRangePastDecorators(node));
-            setOriginalNode(method, node);
-
-            return method;
+            if (updated !== node) {
+                // While we emit the source map for the node after skipping decorators and modifiers,
+                // we need to emit the comments for the original range.
+                setCommentRange(updated, node);
+                setSourceMapRange(updated, moveRangePastDecorators(node));
+            }
+            return updated;
         }
 
         /**
@@ -2102,24 +2062,22 @@ namespace ts {
             if (!shouldEmitAccessorDeclaration(node)) {
                 return undefined;
             }
-
-            const accessor = createGetAccessor(
+            const updated = updateGetAccessor(
+                node,
                 /*decorators*/ undefined,
                 visitNodes(node.modifiers, modifierVisitor, isModifier),
                 visitPropertyNameOfClassElement(node),
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                node.body ? visitEachChild(node.body, visitor, context) : createBlock([]),
-                /*location*/ node
+                visitFunctionBody(node.body, visitor, context) || createBlock([])
             );
-
-            // While we emit the source map for the node after skipping decorators and modifiers,
-            // we need to emit the comments for the original range.
-            setOriginalNode(accessor, node);
-            setCommentRange(accessor, node);
-            setSourceMapRange(accessor, moveRangePastDecorators(node));
-
-            return accessor;
+            if (updated !== node) {
+                // While we emit the source map for the node after skipping decorators and modifiers,
+                // we need to emit the comments for the original range.
+                setCommentRange(updated, node);
+                setSourceMapRange(updated, moveRangePastDecorators(node));
+            }
+            return updated;
         }
 
         /**
@@ -2135,23 +2093,21 @@ namespace ts {
             if (!shouldEmitAccessorDeclaration(node)) {
                 return undefined;
             }
-
-            const accessor = createSetAccessor(
+            const updated = updateSetAccessor(
+                node,
                 /*decorators*/ undefined,
                 visitNodes(node.modifiers, modifierVisitor, isModifier),
                 visitPropertyNameOfClassElement(node),
-                visitNodes(node.parameters, visitor, isParameter),
-                node.body ? visitEachChild(node.body, visitor, context) : createBlock([]),
-                /*location*/ node
+                visitParameterList(node.parameters, visitor, context),
+                visitFunctionBody(node.body, visitor, context) || createBlock([])
             );
-
-            // While we emit the source map for the node after skipping decorators and modifiers,
-            // we need to emit the comments for the original range.
-            setOriginalNode(accessor, node);
-            setCommentRange(accessor, node);
-            setSourceMapRange(accessor, moveRangePastDecorators(node));
-
-            return accessor;
+            if (updated !== node) {
+                // While we emit the source map for the node after skipping decorators and modifiers,
+                // we need to emit the comments for the original range.
+                setCommentRange(updated, node);
+                setSourceMapRange(updated, moveRangePastDecorators(node));
+            }
+            return updated;
         }
 
         /**
@@ -2168,27 +2124,22 @@ namespace ts {
             if (!shouldEmitFunctionLikeDeclaration(node)) {
                 return createNotEmittedStatement(node);
             }
-
-            const func = createFunctionDeclaration(
+            const updated = updateFunctionDeclaration(
+                node,
                 /*decorators*/ undefined,
                 visitNodes(node.modifiers, modifierVisitor, isModifier),
-                node.asteriskToken,
                 node.name,
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                transformFunctionBody(node),
-                /*location*/ node
+                visitFunctionBody(node.body, visitor, context) || createBlock([])
             );
-            setOriginalNode(func, node);
-
             if (isNamespaceExport(node)) {
-                const statements: Statement[] = [func];
+                const statements: Statement[] = [updated];
                 addExportMemberAssignment(statements, node);
                 return statements;
             }
-
-            return func;
+            return updated;
         }
 
         /**
@@ -2203,21 +2154,16 @@ namespace ts {
             if (nodeIsMissing(node.body)) {
                 return createOmittedExpression();
             }
-
-            const func = createFunctionExpression(
+            const updated = updateFunctionExpression(
+                node,
                 visitNodes(node.modifiers, modifierVisitor, isModifier),
-                node.asteriskToken,
                 node.name,
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                transformFunctionBody(node),
-                /*location*/ node
+                visitFunctionBody(node.body, visitor, context)
             );
-
-            setOriginalNode(func, node);
-
-            return func;
+            return updated;
         }
 
         /**
@@ -2226,62 +2172,15 @@ namespace ts {
          * - The node has type annotations
          */
         function visitArrowFunction(node: ArrowFunction) {
-            const func = createArrowFunction(
+            const updated = updateArrowFunction(
+                node,
                 visitNodes(node.modifiers, modifierVisitor, isModifier),
                 /*typeParameters*/ undefined,
-                visitNodes(node.parameters, visitor, isParameter),
+                visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
-                node.equalsGreaterThanToken,
-                transformConciseBody(node),
-                /*location*/ node
+                visitFunctionBody(node.body, visitor, context)
             );
-
-            setOriginalNode(func, node);
-
-            return func;
-        }
-
-        function transformFunctionBody(node: MethodDeclaration | AccessorDeclaration | FunctionDeclaration | FunctionExpression): FunctionBody {
-            return transformFunctionBodyWorker(node.body);
-        }
-
-        function transformFunctionBodyWorker(body: Block, start = 0) {
-            const savedCurrentScope = currentScope;
-            const savedCurrentScopeFirstDeclarationsOfName = currentScopeFirstDeclarationsOfName;
-            currentScope = body;
-            currentScopeFirstDeclarationsOfName = createMap<Node>();
-            startLexicalEnvironment();
-
-            const statements = visitNodes(body.statements, visitor, isStatement, start);
-            const visited = updateBlock(body, statements);
-            const declarations = endLexicalEnvironment();
-            currentScope = savedCurrentScope;
-            currentScopeFirstDeclarationsOfName = savedCurrentScopeFirstDeclarationsOfName;
-            return mergeFunctionBodyLexicalEnvironment(visited, declarations);
-        }
-
-        function transformConciseBody(node: ArrowFunction): ConciseBody {
-            return transformConciseBodyWorker(node.body, /*forceBlockFunctionBody*/ false);
-        }
-
-        function transformConciseBodyWorker(body: Block | Expression, forceBlockFunctionBody: boolean) {
-            if (isBlock(body)) {
-                return transformFunctionBodyWorker(body);
-            }
-            else {
-                startLexicalEnvironment();
-                const visited: Expression | Block = visitNode(body, visitor, isConciseBody);
-                const declarations = endLexicalEnvironment();
-                const merged = mergeFunctionBodyLexicalEnvironment(visited, declarations);
-                if (forceBlockFunctionBody && !isBlock(merged)) {
-                    return createBlock([
-                        createReturn(<Expression>merged)
-                    ]);
-                }
-                else {
-                    return merged;
-                }
-            }
+            return updated;
         }
 
         /**
@@ -2349,11 +2248,13 @@ namespace ts {
         function transformInitializedVariable(node: VariableDeclaration): Expression {
             const name = node.name;
             if (isBindingPattern(name)) {
-                return flattenVariableDestructuringToExpression(
+                return flattenDestructuringAssignment(
                     node,
-                    hoistVariableDeclaration,
-                    createNamespaceExportExpression,
-                    visitor
+                    visitor,
+                    context,
+                    FlattenLevel.All,
+                    /*needsValue*/ false,
+                    createNamespaceExportExpression
                 );
             }
             else {
@@ -2830,7 +2731,7 @@ namespace ts {
             let blockLocation: TextRange;
             const body = node.body;
             if (body.kind === SyntaxKind.ModuleBlock) {
-                addRange(statements, visitNodes((<ModuleBlock>body).statements, namespaceElementVisitor, isStatement));
+                saveStateAndInvoke(body, body => addRange(statements, visitNodes((<ModuleBlock>body).statements, namespaceElementVisitor, isStatement)));
                 statementsLocation = (<ModuleBlock>body).statements;
                 blockLocation = body;
             }
@@ -3353,7 +3254,7 @@ namespace ts {
 
         function trySubstituteNamespaceExportedName(node: Identifier): Expression {
             // If this is explicitly a local name, do not substitute.
-            if (enabledSubstitutions & applicableSubstitutions && !isLocalName(node)) {
+            if (enabledSubstitutions & applicableSubstitutions && !isGeneratedIdentifier(node) && !isLocalName(node)) {
                 // If we are nested within a namespace declaration, we may need to qualifiy
                 // an identifier that is exported from a merged namespace.
                 const container = resolver.getReferencedExportContainer(node, /*prefixLocals*/ false);
@@ -3408,4 +3309,77 @@ namespace ts {
                 : undefined;
         }
     }
+
+    const paramHelper: EmitHelper = {
+        name: "typescript:param",
+        scoped: false,
+        priority: 4,
+        text: `
+            var __param = (this && this.__param) || function (paramIndex, decorator) {
+                return function (target, key) { decorator(target, key, paramIndex); }
+            };`
+    };
+
+    function createParamHelper(context: TransformationContext, expression: Expression, parameterOffset: number, location?: TextRange) {
+        context.requestEmitHelper(paramHelper);
+        return createCall(
+            getHelperName("__param"),
+            /*typeArguments*/ undefined,
+            [
+                createLiteral(parameterOffset),
+                expression
+            ],
+            location
+        );
+    }
+
+    const metadataHelper: EmitHelper = {
+        name: "typescript:metadata",
+        scoped: false,
+        priority: 3,
+        text: `
+            var __metadata = (this && this.__metadata) || function (k, v) {
+                if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+            };`
+    };
+
+    function createMetadataHelper(context: TransformationContext, metadataKey: string, metadataValue: Expression) {
+        context.requestEmitHelper(metadataHelper);
+        return createCall(
+            getHelperName("__metadata"),
+            /*typeArguments*/ undefined,
+            [
+                createLiteral(metadataKey),
+                metadataValue
+            ]
+        );
+    }
+
+    const decorateHelper: EmitHelper = {
+        name: "typescript:decorate",
+        scoped: false,
+        priority: 2,
+        text: `
+            var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+                var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+                if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+                else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+                return c > 3 && r && Object.defineProperty(target, key, r), r;
+            };`
+    };
+
+    function createDecorateHelper(context: TransformationContext, decoratorExpressions: Expression[], target: Expression, memberName?: Expression, descriptor?: Expression, location?: TextRange) {
+        context.requestEmitHelper(decorateHelper);
+        const argumentsArray: Expression[] = [];
+        argumentsArray.push(createArrayLiteral(decoratorExpressions, /*location*/ undefined, /*multiLine*/ true));
+        argumentsArray.push(target);
+        if (memberName) {
+            argumentsArray.push(memberName);
+            if (descriptor) {
+                argumentsArray.push(descriptor);
+            }
+        }
+
+        return createCall(getHelperName("__decorate"), /*typeArguments*/ undefined, argumentsArray, location);
+    }
 }

src/compiler/tsc.ts

@@ -43,66 +43,6 @@ namespace ts {
         }
     }
 
-    /**
-     * Checks to see if the locale is in the appropriate format,
-     * and if it is, attempts to set the appropriate language.
-     */
-    function validateLocaleAndSetLanguage(locale: string, errors: Diagnostic[]): boolean {
-        const matchResult = /^([a-z]+)([_\-]([a-z]+))?$/.exec(locale.toLowerCase());
-
-        if (!matchResult) {
-            errors.push(createCompilerDiagnostic(Diagnostics.Locale_must_be_of_the_form_language_or_language_territory_For_example_0_or_1, "en", "ja-jp"));
-            return false;
-        }
-
-        const language = matchResult[1];
-        const territory = matchResult[3];
-
-        // First try the entire locale, then fall back to just language if that's all we have.
-        // Either ways do not fail, and fallback to the English diagnostic strings.
-        if (!trySetLanguageAndTerritory(language, territory, errors)) {
-            trySetLanguageAndTerritory(language, undefined, errors);
-        }
-
-        return true;
-    }
-
-    function trySetLanguageAndTerritory(language: string, territory: string, errors: Diagnostic[]): boolean {
-        const compilerFilePath = normalizePath(sys.getExecutingFilePath());
-        const containingDirectoryPath = getDirectoryPath(compilerFilePath);
-
-        let filePath = combinePaths(containingDirectoryPath, language);
-
-        if (territory) {
-            filePath = filePath + "-" + territory;
-        }
-
-        filePath = sys.resolvePath(combinePaths(filePath, "diagnosticMessages.generated.json"));
-
-        if (!sys.fileExists(filePath)) {
-            return false;
-        }
-
-        // TODO: Add codePage support for readFile?
-        let fileContents = "";
-        try {
-            fileContents = sys.readFile(filePath);
-        }
-        catch (e) {
-            errors.push(createCompilerDiagnostic(Diagnostics.Unable_to_open_file_0, filePath));
-            return false;
-        }
-        try {
-            ts.localizedDiagnosticMessages = JSON.parse(fileContents);
-        }
-        catch (e) {
-            errors.push(createCompilerDiagnostic(Diagnostics.Corrupted_locale_file_0, filePath));
-            return false;
-        }
-
-        return true;
-    }
-
     function countLines(program: Program): number {
         let count = 0;
         forEach(program.getSourceFiles(), file => {
@@ -263,7 +203,7 @@ namespace ts {
                 reportDiagnostic(createCompilerDiagnostic(Diagnostics.The_current_host_does_not_support_the_0_option, "--locale"), /* host */ undefined);
                 return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
             }
-            validateLocaleAndSetLanguage(commandLine.options.locale, commandLine.errors);
+            validateLocaleAndSetLanguage(commandLine.options.locale, sys, commandLine.errors);
         }
 
         // If there are any errors due to command line parsing and/or

src/compiler/tsconfig.json

@@ -11,7 +11,8 @@
         "stripInternal": true,
         "target": "es5",
         "noUnusedLocals": true,
-        "noUnusedParameters": true
+        "noUnusedParameters": true,
+        "types": [ ]
     },
     "files": [
         "core.ts",
@@ -27,6 +28,7 @@
         "visitor.ts",
         "transformers/ts.ts",
         "transformers/jsx.ts",
+        "transformers/esnext.ts",
         "transformers/es2017.ts",
         "transformers/es2016.ts",
         "transformers/es2015.ts",

src/compiler/types.ts

@@ -219,6 +219,7 @@ namespace ts {
         ThisType,
         TypeOperator,
         IndexedAccessType,
+        MappedType,
         LiteralType,
         // Binding patterns
         ObjectBindingPattern,
@@ -246,12 +247,13 @@ namespace ts {
         ConditionalExpression,
         TemplateExpression,
         YieldExpression,
-        SpreadElementExpression,
+        SpreadElement,
         ClassExpression,
         OmittedExpression,
         ExpressionWithTypeArguments,
         AsExpression,
         NonNullExpression,
+        MetaProperty,
 
         // Misc
         TemplateSpan,
@@ -320,6 +322,7 @@ namespace ts {
         // Property assignments
         PropertyAssignment,
         ShorthandPropertyAssignment,
+        SpreadAssignment,
 
         // Enum
         EnumMember,
@@ -347,6 +350,7 @@ namespace ts {
         JSDocThisType,
         JSDocComment,
         JSDocTag,
+        JSDocAugmentsTag,
         JSDocParameterTag,
         JSDocReturnTag,
         JSDocTypeTag,
@@ -414,25 +418,20 @@ namespace ts {
         HasImplicitReturn =  1 << 7,  // If function implicitly returns on one of codepaths (initialized by binding)
         HasExplicitReturn =  1 << 8,  // If function has explicit reachable return on one of codepaths (initialized by binding)
         GlobalAugmentation = 1 << 9,  // Set if module declaration is an augmentation for the global scope
-        HasClassExtends =    1 << 10, // If the file has a non-ambient class with an extends clause in ES5 or lower (initialized by binding)
-        HasDecorators =      1 << 11, // If the file has decorators (initialized by binding)
-        HasParamDecorators = 1 << 12, // If the file has parameter decorators (initialized by binding)
-        HasAsyncFunctions =  1 << 13, // If the file has async functions (initialized by binding)
-        HasJsxSpreadAttributes = 1 << 14, // If the file as JSX spread attributes (initialized by binding)
-        DisallowInContext =  1 << 15, // If node was parsed in a context where 'in-expressions' are not allowed
-        YieldContext =       1 << 16, // If node was parsed in the 'yield' context created when parsing a generator
-        DecoratorContext =   1 << 17, // If node was parsed as part of a decorator
-        AwaitContext =       1 << 18, // If node was parsed in the 'await' context created when parsing an async function
-        ThisNodeHasError =   1 << 19, // If the parser encountered an error when parsing the code that created this node
-        JavaScriptFile =     1 << 20, // If node was parsed in a JavaScript
-        ThisNodeOrAnySubNodesHasError = 1 << 21, // If this node or any of its children had an error
-        HasAggregatedChildData = 1 << 22, // If we've computed data from children and cached it in this node
+        HasAsyncFunctions =  1 << 10, // If the file has async functions (initialized by binding)
+        DisallowInContext =  1 << 11, // If node was parsed in a context where 'in-expressions' are not allowed
+        YieldContext =       1 << 12, // If node was parsed in the 'yield' context created when parsing a generator
+        DecoratorContext =   1 << 13, // If node was parsed as part of a decorator
+        AwaitContext =       1 << 14, // If node was parsed in the 'await' context created when parsing an async function
+        ThisNodeHasError =   1 << 15, // If the parser encountered an error when parsing the code that created this node
+        JavaScriptFile =     1 << 16, // If node was parsed in a JavaScript
+        ThisNodeOrAnySubNodesHasError = 1 << 17, // If this node or any of its children had an error
+        HasAggregatedChildData = 1 << 18, // If we've computed data from children and cached it in this node
 
         BlockScoped = Let | Const,
 
         ReachabilityCheckFlags = HasImplicitReturn | HasExplicitReturn,
-        EmitHelperFlags = HasClassExtends | HasDecorators | HasParamDecorators | HasAsyncFunctions | HasJsxSpreadAttributes,
-        ReachabilityAndEmitFlags = ReachabilityCheckFlags | EmitHelperFlags,
+        ReachabilityAndEmitFlags = ReachabilityCheckFlags | HasAsyncFunctions,
 
         // Parsing context flags
         ContextFlags = DisallowInContext | YieldContext | DecoratorContext | AwaitContext | JavaScriptFile,
@@ -454,7 +453,6 @@ namespace ts {
         Async =              1 << 8,  // Property/Method/Function
         Default =            1 << 9,  // Function/Class (export default declaration)
         Const =              1 << 11, // Variable declaration
-
         HasComputedFlags =   1 << 29, // Modifier flags have been computed
 
         AccessibilityModifier = Public | Private | Protected,
@@ -494,7 +492,8 @@ namespace ts {
         parent?: Node;                                  // Parent node (initialized by binding)
         /* @internal */ original?: Node;                // The original node if this is an updated node.
         /* @internal */ startsOnNewLine?: boolean;      // Whether a synthesized node should start on a new line (used by transforms).
-        /* @internal */ jsDocComments?: JSDoc[];        // JSDoc for the node, if it has any.
+        /* @internal */ jsDoc?: JSDoc[];                // JSDoc that directly precedes this node
+        /* @internal */ jsDocCache?: (JSDoc | JSDocTag)[]; // All JSDoc that applies to the node, including parent docs and @param tags
         /* @internal */ symbol?: Symbol;                // Symbol declared by node (initialized by binding)
         /* @internal */ locals?: SymbolTable;           // Locals associated with node (initialized by binding)
         /* @internal */ nextContainer?: Node;           // Next container in declaration order (initialized by binding)
@@ -505,6 +504,7 @@ namespace ts {
 
     export interface NodeArray<T extends Node> extends Array<T>, TextRange {
         hasTrailingComma?: boolean;
+        /* @internal */ transformFlags?: TransformFlags;
     }
 
     export interface Token<TKind extends SyntaxKind> extends Node {
@@ -519,6 +519,7 @@ namespace ts {
     export type EqualsGreaterThanToken = Token<SyntaxKind.EqualsGreaterThanToken>;
     export type EndOfFileToken = Token<SyntaxKind.EndOfFileToken>;
     export type AtToken = Token<SyntaxKind.AtToken>;
+    export type ReadonlyToken = Token<SyntaxKind.ReadonlyKeyword>;
 
     export type Modifier
         = Token<SyntaxKind.AbstractKeyword>
@@ -575,9 +576,9 @@ namespace ts {
 
     export type EntityName = Identifier | QualifiedName;
 
-    export type PropertyName = Identifier | LiteralExpression | ComputedPropertyName;
+    export type PropertyName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName;
 
-    export type DeclarationName = Identifier | LiteralExpression | ComputedPropertyName | BindingPattern;
+    export type DeclarationName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName | BindingPattern;
 
     export interface Declaration extends Node {
         _declarationBrand: any;
@@ -585,7 +586,7 @@ namespace ts {
     }
 
     export interface DeclarationStatement extends Declaration, Statement {
-        name?: Identifier | LiteralExpression;
+        name?: Identifier | StringLiteral | NumericLiteral;
     }
 
     export interface ComputedPropertyName extends Node {
@@ -649,7 +650,7 @@ namespace ts {
     export interface BindingElement extends Declaration {
         kind: SyntaxKind.BindingElement;
         propertyName?: PropertyName;        // Binding property name (in object binding pattern)
-        dotDotDotToken?: DotDotDotToken;              // Present on rest binding element
+        dotDotDotToken?: DotDotDotToken;    // Present on rest element (in object binding pattern)
         name: BindingName;                  // Declared binding element name
         initializer?: Expression;           // Optional initializer
     }
@@ -675,7 +676,7 @@ namespace ts {
         name?: PropertyName;
     }
 
-    export type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration;
+    export type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration | SpreadAssignment;
 
     export interface PropertyAssignment extends ObjectLiteralElement {
         kind: SyntaxKind.PropertyAssignment;
@@ -694,6 +695,11 @@ namespace ts {
         objectAssignmentInitializer?: Expression;
     }
 
+    export interface SpreadAssignment extends ObjectLiteralElement {
+        kind: SyntaxKind.SpreadAssignment;
+        expression: Expression;
+    }
+
     // SyntaxKind.VariableDeclaration
     // SyntaxKind.Parameter
     // SyntaxKind.BindingElement
@@ -715,22 +721,20 @@ namespace ts {
         name: PropertyName;
     }
 
-    export interface BindingPattern extends Node {
-        elements: NodeArray<BindingElement | ArrayBindingElement>;
-    }
-
-    export interface ObjectBindingPattern extends BindingPattern {
+    export interface ObjectBindingPattern extends Node {
         kind: SyntaxKind.ObjectBindingPattern;
         elements: NodeArray<BindingElement>;
     }
 
-    export type ArrayBindingElement = BindingElement | OmittedExpression;
-
-    export interface ArrayBindingPattern extends BindingPattern {
+    export interface ArrayBindingPattern extends Node {
         kind: SyntaxKind.ArrayBindingPattern;
         elements: NodeArray<ArrayBindingElement>;
     }
 
+    export type BindingPattern = ObjectBindingPattern | ArrayBindingPattern;
+
+    export type ArrayBindingElement = BindingElement | OmittedExpression;
+
     /**
      * Several node kinds share function-like features such as a signature,
      * a name, and a body. These nodes should extend FunctionLikeDeclaration.
@@ -897,6 +901,14 @@ namespace ts {
         indexType: TypeNode;
     }
 
+    export interface MappedTypeNode extends TypeNode, Declaration {
+        kind: SyntaxKind.MappedType;
+        readonlyToken?: ReadonlyToken;
+        typeParameter: TypeParameterDeclaration;
+        questionToken?: QuestionToken;
+        type?: TypeNode;
+    }
+
     export interface LiteralTypeNode extends TypeNode {
         kind: SyntaxKind.LiteralType;
         literal: Expression;
@@ -904,7 +916,7 @@ namespace ts {
 
     export interface StringLiteral extends LiteralExpression {
         kind: SyntaxKind.StringLiteral;
-        /* @internal */ textSourceNode?: Identifier | StringLiteral; // Allows a StringLiteral to get its text from another node (used by transforms).
+        /* @internal */ textSourceNode?: Identifier | StringLiteral | NumericLiteral; // Allows a StringLiteral to get its text from another node (used by transforms).
     }
 
     // Note: 'brands' in our syntax nodes serve to give us a small amount of nominal typing.
@@ -1169,20 +1181,64 @@ namespace ts {
         right: Expression;
     }
 
-    export interface AssignmentExpression extends BinaryExpression {
+    export type AssignmentOperatorToken = Token<AssignmentOperator>;
+
+    export interface AssignmentExpression<TOperator extends AssignmentOperatorToken> extends BinaryExpression {
         left: LeftHandSideExpression;
-        operatorToken: Token<SyntaxKind.EqualsToken>;
+        operatorToken: TOperator;
     }
 
-    export interface ObjectDestructuringAssignment extends AssignmentExpression {
+    export interface ObjectDestructuringAssignment extends AssignmentExpression<EqualsToken> {
         left: ObjectLiteralExpression;
     }
 
-    export interface ArrayDestructuringAssignment extends AssignmentExpression {
+    export interface ArrayDestructuringAssignment extends AssignmentExpression<EqualsToken> {
         left: ArrayLiteralExpression;
     }
 
-    export type DestructuringAssignment = ObjectDestructuringAssignment | ArrayDestructuringAssignment;
+    export type DestructuringAssignment
+        = ObjectDestructuringAssignment
+        | ArrayDestructuringAssignment
+        ;
+
+    export type BindingOrAssignmentElement
+        = VariableDeclaration
+        | ParameterDeclaration
+        | BindingElement
+        | PropertyAssignment // AssignmentProperty
+        | ShorthandPropertyAssignment // AssignmentProperty
+        | SpreadAssignment // AssignmentRestProperty
+        | OmittedExpression // Elision
+        | SpreadElement // AssignmentRestElement
+        | ArrayLiteralExpression // ArrayAssignmentPattern
+        | ObjectLiteralExpression // ObjectAssignmentPattern
+        | AssignmentExpression<EqualsToken> // AssignmentElement
+        | Identifier // DestructuringAssignmentTarget
+        | PropertyAccessExpression // DestructuringAssignmentTarget
+        | ElementAccessExpression // DestructuringAssignmentTarget
+        ;
+
+    export type BindingOrAssignmentElementRestIndicator
+        = DotDotDotToken // from BindingElement
+        | SpreadElement // AssignmentRestElement
+        | SpreadAssignment // AssignmentRestProperty
+        ;
+
+    export type BindingOrAssignmentElementTarget = BindingOrAssignmentPattern | Expression;
+
+    export type ObjectBindingOrAssignmentPattern
+        = ObjectBindingPattern
+        | ObjectLiteralExpression // ObjectAssignmentPattern
+        ;
+
+    export type ArrayBindingOrAssignmentPattern
+        = ArrayBindingPattern
+        | ArrayLiteralExpression // ArrayAssignmentPattern
+        ;
+
+    export type AssignmentPattern = ObjectLiteralExpression | ArrayLiteralExpression;
+
+    export type BindingOrAssignmentPattern = ObjectBindingOrAssignmentPattern | ArrayBindingOrAssignmentPattern;
 
     export interface ConditionalExpression extends Expression {
         kind: SyntaxKind.ConditionalExpression;
@@ -1279,8 +1335,8 @@ namespace ts {
         multiLine?: boolean;
     }
 
-    export interface SpreadElementExpression extends Expression {
-        kind: SyntaxKind.SpreadElementExpression;
+    export interface SpreadElement extends Expression {
+        kind: SyntaxKind.SpreadElement;
         expression: Expression;
     }
 
@@ -1388,6 +1444,14 @@ namespace ts {
         expression: Expression;
     }
 
+    // NOTE: MetaProperty is really a MemberExpression, but we consider it a PrimaryExpression
+    //       for the same reasons we treat NewExpression as a PrimaryExpression.
+    export interface MetaProperty extends PrimaryExpression {
+        kind: SyntaxKind.MetaProperty;
+        keywordToken: SyntaxKind;
+        name: Identifier;
+    }
+
     /// A JSX expression of the form <TagName attrs>...</TagName>
     export interface JsxElement extends PrimaryExpression {
         kind: SyntaxKind.JsxElement;
@@ -1436,6 +1500,7 @@ namespace ts {
 
     export interface JsxExpression extends Expression {
         kind: SyntaxKind.JsxExpression;
+        dotDotDotToken?: Token<SyntaxKind.DotDotDotToken>;
         expression?: Expression;
     }
 
@@ -1503,6 +1568,11 @@ namespace ts {
         expression: Expression;
     }
 
+    /* @internal */
+    export interface PrologueDirective extends ExpressionStatement {
+        expression: StringLiteral;
+    }
+
     export interface IfStatement extends Statement {
         kind: SyntaxKind.IfStatement;
         expression: Expression;
@@ -1687,7 +1757,7 @@ namespace ts {
 
     export interface ModuleDeclaration extends DeclarationStatement {
         kind: SyntaxKind.ModuleDeclaration;
-        name: Identifier | LiteralExpression;
+        name: Identifier | StringLiteral;
         body?: ModuleBlock | NamespaceDeclaration | JSDocNamespaceDeclaration | Identifier;
     }
 
@@ -1893,7 +1963,7 @@ namespace ts {
 
     export interface JSDocRecordMember extends PropertySignature {
         kind: SyntaxKind.JSDocRecordMember;
-        name: Identifier | LiteralExpression;
+        name: Identifier | StringLiteral | NumericLiteral;
         type?: JSDocType;
     }
 
@@ -1913,6 +1983,11 @@ namespace ts {
         kind: SyntaxKind.JSDocTag;
     }
 
+    export interface JSDocAugmentsTag extends JSDocTag {
+        kind: SyntaxKind.JSDocAugmentsTag;
+        typeExpression: JSDocTypeExpression;
+    }
+
     export interface JSDocTemplateTag extends JSDocTag {
         kind: SyntaxKind.JSDocTemplateTag;
         typeParameters: NodeArray<TypeParameterDeclaration>;
@@ -2103,8 +2178,6 @@ namespace ts {
         /* @internal */ moduleAugmentations: LiteralExpression[];
         /* @internal */ patternAmbientModules?: PatternAmbientModule[];
         /* @internal */ ambientModuleNames: string[];
-        // The synthesized identifier for an imported external helpers module.
-        /* @internal */ externalHelpersModuleName?: Identifier;
     }
 
     export interface ScriptReferenceHost {
@@ -2298,6 +2371,8 @@ namespace ts {
         isOptionalParameter(node: ParameterDeclaration): boolean;
         getAmbientModules(): Symbol[];
 
+        tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined;
+
         /* @internal */ tryFindAmbientModuleWithoutAugmentations(moduleName: string): Symbol;
 
         // Should not be called directly.  Should only be accessed through the Program instance.
@@ -2331,6 +2406,7 @@ namespace ts {
         writeSpace(text: string): void;
         writeStringLiteral(text: string): void;
         writeParameter(text: string): void;
+        writeProperty(text: string): void;
         writeSymbol(text: string, symbol: Symbol): void;
         writeLine(): void;
         increaseIndent(): void;
@@ -2381,6 +2457,12 @@ namespace ts {
         CannotBeNamed
     }
 
+    /* @internal */
+    export const enum SyntheticSymbolKind {
+        UnionOrIntersection,
+        Spread
+    }
+
     export const enum TypePredicateKind {
         This,
         Identifier
@@ -2473,6 +2555,7 @@ namespace ts {
         getTypeReferenceDirectivesForSymbol(symbol: Symbol, meaning?: SymbolFlags): string[];
         isLiteralConstDeclaration(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration): boolean;
         writeLiteralConstValue(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration, writer: SymbolWriter): void;
+        getJsxFactoryEntity(): EntityName;
     }
 
     export const enum SymbolFlags {
@@ -2488,7 +2571,7 @@ namespace ts {
         RegularEnum             = 0x00000100,  // Enum
         ValueModule             = 0x00000200,  // Instantiated module
         NamespaceModule         = 0x00000400,  // Uninstantiated module
-        TypeLiteral             = 0x00000800,  // Type Literal
+        TypeLiteral             = 0x00000800,  // Type Literal or mapped type
         ObjectLiteral           = 0x00001000,  // Object Literal
         Method                  = 0x00002000,  // Method
         Constructor             = 0x00004000,  // Constructor
@@ -2592,7 +2675,9 @@ namespace ts {
         instantiations?: Map<Type>;         // Instantiations of generic type alias (undefined if non-generic)
         mapper?: TypeMapper;                // Type mapper for instantiation alias
         referenced?: boolean;               // True if alias symbol has been referenced as a value
-        containingType?: UnionOrIntersectionType; // Containing union or intersection type for synthetic property
+        containingType?: UnionOrIntersectionType;  // Containing union or intersection type for synthetic property
+        leftSpread?: Symbol;                // Left source for synthetic spread property
+        rightSpread?: Symbol;               // Right source for synthetic spread property
         hasNonUniformType?: boolean;        // True if constituents have non-uniform types
         isPartial?: boolean;                // True if syntheric property of union type occurs in some but not all constituents
         isDiscriminantProperty?: boolean;   // True if discriminant synthetic property
@@ -2627,6 +2712,7 @@ namespace ts {
         TypeChecked                         = 0x00000001,  // Node has been type checked
         LexicalThis                         = 0x00000002,  // Lexical 'this' reference
         CaptureThis                         = 0x00000004,  // Lexical 'this' used in body
+        CaptureNewTarget                    = 0x00000008,  // Lexical 'new.target' used in body
         SuperInstance                       = 0x00000100,  // Instance 'super' reference
         SuperStatic                         = 0x00000200,  // Static 'super' reference
         ContextChecked                      = 0x00000400,  // Contextual types have been assigned
@@ -2653,6 +2739,7 @@ namespace ts {
         resolvedSignature?: Signature;    // Cached signature of signature node or call expression
         resolvedSymbol?: Symbol;          // Cached name resolution result
         resolvedIndexInfo?: IndexInfo;    // Cached indexing info resolution result
+        maybeTypePredicate?: boolean;     // Cached check whether call expression might reference a type predicate
         enumMemberValue?: number;         // Constant value of enum member
         isVisible?: boolean;              // Is this node visible
         hasReportedStatementInAmbientContext?: boolean;  // Cache boolean if we report statements in ambient context
@@ -2704,13 +2791,14 @@ namespace ts {
         Intrinsic = Any | String | Number | Boolean | BooleanLiteral | ESSymbol | Void | Undefined | Null | Never,
         /* @internal */
         Primitive = String | Number | Boolean | Enum | ESSymbol | Void | Undefined | Null | Literal,
-        StringLike = String | StringLiteral,
+        StringLike = String | StringLiteral | Index,
         NumberLike = Number | NumberLiteral | Enum | EnumLiteral,
         BooleanLike = Boolean | BooleanLiteral,
         EnumLike = Enum | EnumLiteral,
         UnionOrIntersection = Union | Intersection,
         StructuredType = Object | Union | Intersection,
         StructuredOrTypeParameter = StructuredType | TypeParameter | Index,
+        TypeVariable = TypeParameter | IndexedAccess,
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
@@ -2764,10 +2852,11 @@ namespace ts {
         Reference        = 1 << 2,  // Generic type reference
         Tuple            = 1 << 3,  // Synthesized generic tuple type
         Anonymous        = 1 << 4,  // Anonymous
-        Instantiated     = 1 << 5,  // Instantiated anonymous type
-        ObjectLiteral    = 1 << 6,  // Originates in an object literal
-        EvolvingArray    = 1 << 7,  // Evolving array type
-        ObjectLiteralPatternWithComputedProperties = 1 << 8,  // Object literal pattern with computed properties
+        Mapped           = 1 << 5,  // Mapped
+        Instantiated     = 1 << 6,  // Instantiated anonymous or mapped type
+        ObjectLiteral    = 1 << 7,  // Originates in an object literal
+        EvolvingArray    = 1 << 8,  // Evolving array type
+        ObjectLiteralPatternWithComputedProperties = 1 << 9,  // Object literal pattern with computed properties
         ClassOrInterface = Class | Interface
     }
 
@@ -2820,7 +2909,9 @@ namespace ts {
         /* @internal */
         resolvedProperties: SymbolTable;  // Cache of resolved properties
         /* @internal */
-        couldContainTypeParameters: boolean;
+        resolvedIndexType: IndexType;
+        /* @internal */
+        couldContainTypeVariables: boolean;
     }
 
     export interface UnionType extends UnionOrIntersectionType { }
@@ -2836,6 +2927,16 @@ namespace ts {
         mapper?: TypeMapper;     // Instantiation mapper
     }
 
+    /* @internal */
+    export interface MappedType extends ObjectType {
+        declaration: MappedTypeNode;
+        typeParameter?: TypeParameter;
+        constraintType?: Type;
+        templateType?: Type;
+        modifiersType?: Type;
+        mapper?: TypeMapper;  // Instantiation mapper
+    }
+
     export interface EvolvingArrayType extends ObjectType {
         elementType: Type;      // Element expressions of evolving array type
         finalArrayType?: Type;  // Final array type of evolving array type
@@ -2867,30 +2968,35 @@ namespace ts {
         iteratorElementType?: Type;
     }
 
+    export interface TypeVariable extends Type {
+        /* @internal */
+        resolvedApparentType: Type;
+        /* @internal */
+        resolvedIndexType: IndexType;
+    }
+
     // Type parameters (TypeFlags.TypeParameter)
-    export interface TypeParameter extends Type {
+    export interface TypeParameter extends TypeVariable {
         constraint: Type;        // Constraint
         /* @internal */
         target?: TypeParameter;  // Instantiation target
         /* @internal */
         mapper?: TypeMapper;     // Instantiation mapper
         /* @internal */
-        resolvedApparentType: Type;
-        /* @internal */
-        resolvedIndexType: IndexType;
-        /* @internal */
-        resolvedIndexedAccessTypes: IndexedAccessType[];
-        /* @internal */
         isThisType?: boolean;
     }
 
-    export interface IndexType extends Type {
-        type: TypeParameter;
+    // Indexed access types (TypeFlags.IndexedAccess)
+    // Possible forms are T[xxx], xxx[T], or xxx[keyof T], where T is a type variable
+    export interface IndexedAccessType extends TypeVariable {
+        objectType: Type;
+        indexType: Type;
+        constraint?: Type;
     }
 
-    export interface IndexedAccessType extends Type {
-        objectType: Type;
-        indexType: TypeParameter;
+    // keyof T types (TypeFlags.Index)
+    export interface IndexType extends Type {
+        type: TypeVariable | UnionOrIntersectionType;
     }
 
     export const enum SignatureKind {
@@ -2982,6 +3088,12 @@ namespace ts {
         ThisProperty
     }
 
+    export interface FileExtensionInfo {
+        extension: string;
+        scriptKind: ScriptKind;
+        isMixedContent: boolean;
+    }
+
     export interface DiagnosticMessage {
         key: string;
         category: DiagnosticCategory;
@@ -3060,7 +3172,7 @@ namespace ts {
         moduleResolution?: ModuleResolutionKind;
         newLine?: NewLineKind;
         noEmit?: boolean;
-        /*@internal*/noEmitOverwritenFiles?: boolean;
+        /*@internal*/noEmitForJsFiles?: boolean;
         noEmitHelpers?: boolean;
         noEmitOnError?: boolean;
         noErrorTruncation?: boolean;
@@ -3081,6 +3193,7 @@ namespace ts {
         project?: string;
         /* @internal */ pretty?: DiagnosticStyle;
         reactNamespace?: string;
+        jsxFactory?: string;
         removeComments?: boolean;
         rootDir?: string;
         rootDirs?: string[];
@@ -3096,7 +3209,7 @@ namespace ts {
         target?: ScriptTarget;
         traceResolution?: boolean;
         types?: string[];
-        /** Paths used to used to compute primary types search locations */
+        /** Paths used to compute primary types search locations */
         typeRoots?: string[];
         /*@internal*/ version?: boolean;
         /*@internal*/ watch?: boolean;
@@ -3104,8 +3217,12 @@ namespace ts {
         [option: string]: CompilerOptionsValue | undefined;
     }
 
-    export interface TypingOptions {
+    export interface TypeAcquisition {
+        /* @deprecated typingOptions.enableAutoDiscovery
+         * Use typeAcquisition.enable instead.
+         */
         enableAutoDiscovery?: boolean;
+        enable?: boolean;
         include?: string[];
         exclude?: string[];
         [option: string]: string[] | boolean | undefined;
@@ -3116,7 +3233,7 @@ namespace ts {
         projectRootPath: string;                        // The path to the project root directory
         safeListPath: string;                           // The path used to retrieve the safe list
         packageNameToTypingLocation: Map<string>;       // The map of package names to their cached typing locations
-        typingOptions: TypingOptions;                   // Used to customize the typing inference process
+        typeAcquisition: TypeAcquisition;               // Used to customize the type acquisition process
         compilerOptions: CompilerOptions;               // Used as a source for typing inference
         unresolvedImports: ReadonlyArray<string>;       // List of unresolved module ids from imports
     }
@@ -3163,7 +3280,8 @@ namespace ts {
         ES2015 = 2,
         ES2016 = 3,
         ES2017 = 4,
-        Latest = ES2017,
+        ESNext = 5,
+        Latest = ESNext,
     }
 
     export const enum LanguageVariant {
@@ -3180,7 +3298,7 @@ namespace ts {
     /** Either a parsed command line or a parsed tsconfig.json */
     export interface ParsedCommandLine {
         options: CompilerOptions;
-        typingOptions?: TypingOptions;
+        typeAcquisition?: TypeAcquisition;
         fileNames: string[];
         raw?: any;
         errors: Diagnostic[];
@@ -3425,6 +3543,7 @@ namespace ts {
 
     export interface ResolvedModuleWithFailedLookupLocations {
         resolvedModule: ResolvedModuleFull | undefined;
+        /* @internal */
         failedLookupLocations: string[];
     }
 
@@ -3476,43 +3595,45 @@ namespace ts {
         // - Flags used to indicate that a node or subtree contains syntax that requires transformation.
         TypeScript = 1 << 0,
         ContainsTypeScript = 1 << 1,
-        Jsx = 1 << 2,
-        ContainsJsx = 1 << 3,
-        ES2017 = 1 << 4,
-        ContainsES2017 = 1 << 5,
-        ES2016 = 1 << 6,
-        ContainsES2016 = 1 << 7,
-        ES2015 = 1 << 8,
-        ContainsES2015 = 1 << 9,
-        Generator = 1 << 10,
-        ContainsGenerator = 1 << 11,
-        DestructuringAssignment = 1 << 12,
-        ContainsDestructuringAssignment = 1 << 13,
+        ContainsJsx = 1 << 2,
+        ContainsESNext = 1 << 3,
+        ContainsES2017 = 1 << 4,
+        ContainsES2016 = 1 << 5,
+        ES2015 = 1 << 6,
+        ContainsES2015 = 1 << 7,
+        Generator = 1 << 8,
+        ContainsGenerator = 1 << 9,
+        DestructuringAssignment = 1 << 10,
+        ContainsDestructuringAssignment = 1 << 11,
 
         // Markers
         // - Flags used to indicate that a subtree contains a specific transformation.
-        ContainsDecorators = 1 << 14,
-        ContainsPropertyInitializer = 1 << 15,
-        ContainsLexicalThis = 1 << 16,
-        ContainsCapturedLexicalThis = 1 << 17,
-        ContainsLexicalThisInComputedPropertyName = 1 << 18,
-        ContainsDefaultValueAssignments = 1 << 19,
-        ContainsParameterPropertyAssignments = 1 << 20,
-        ContainsSpreadElementExpression = 1 << 21,
-        ContainsComputedPropertyName = 1 << 22,
-        ContainsBlockScopedBinding = 1 << 23,
-        ContainsBindingPattern = 1 << 24,
-        ContainsYield = 1 << 25,
-        ContainsHoistedDeclarationOrCompletion = 1 << 26,
+        ContainsDecorators = 1 << 12,
+        ContainsPropertyInitializer = 1 << 13,
+        ContainsLexicalThis = 1 << 14,
+        ContainsCapturedLexicalThis = 1 << 15,
+        ContainsLexicalThisInComputedPropertyName = 1 << 16,
+        ContainsDefaultValueAssignments = 1 << 17,
+        ContainsParameterPropertyAssignments = 1 << 18,
+        ContainsSpread = 1 << 19,
+        ContainsObjectSpread = 1 << 20,
+        ContainsRest = ContainsSpread,
+        ContainsObjectRest = ContainsObjectSpread,
+        ContainsComputedPropertyName = 1 << 21,
+        ContainsBlockScopedBinding = 1 << 22,
+        ContainsBindingPattern = 1 << 23,
+        ContainsYield = 1 << 24,
+        ContainsHoistedDeclarationOrCompletion = 1 << 25,
 
         HasComputedFlags = 1 << 29, // Transform flags have been computed.
 
         // Assertions
         // - Bitmasks that are used to assert facts about the syntax of a node and its subtree.
         AssertTypeScript = TypeScript | ContainsTypeScript,
-        AssertJsx = Jsx | ContainsJsx,
-        AssertES2017 = ES2017 | ContainsES2017,
-        AssertES2016 = ES2016 | ContainsES2016,
+        AssertJsx = ContainsJsx,
+        AssertESNext = ContainsESNext,
+        AssertES2017 = ContainsES2017,
+        AssertES2016 = ContainsES2016,
         AssertES2015 = ES2015 | ContainsES2015,
         AssertGenerator = Generator | ContainsGenerator,
         AssertDestructuringAssignment = DestructuringAssignment | ContainsDestructuringAssignment,
@@ -3520,18 +3641,20 @@ namespace ts {
         // Scope Exclusions
         // - Bitmasks that exclude flags from propagating out of a specific context
         //   into the subtree flags of their container.
-        NodeExcludes = TypeScript | Jsx | ES2017 | ES2016 | ES2015 | DestructuringAssignment | Generator | HasComputedFlags,
-        ArrowFunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
-        FunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsCapturedLexicalThis | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
-        ConstructorExcludes = NodeExcludes | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
-        MethodOrAccessorExcludes = NodeExcludes | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
+        NodeExcludes = TypeScript | ES2015 | DestructuringAssignment | Generator | HasComputedFlags,
+        ArrowFunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion | ContainsBindingPattern | ContainsObjectRest,
+        FunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsCapturedLexicalThis | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion | ContainsBindingPattern | ContainsObjectRest,
+        ConstructorExcludes = NodeExcludes | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion | ContainsBindingPattern | ContainsObjectRest,
+        MethodOrAccessorExcludes = NodeExcludes | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion | ContainsBindingPattern | ContainsObjectRest,
         ClassExcludes = NodeExcludes | ContainsDecorators | ContainsPropertyInitializer | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsComputedPropertyName | ContainsParameterPropertyAssignments | ContainsLexicalThisInComputedPropertyName,
         ModuleExcludes = NodeExcludes | ContainsDecorators | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsHoistedDeclarationOrCompletion,
         TypeExcludes = ~ContainsTypeScript,
-        ObjectLiteralExcludes = NodeExcludes | ContainsDecorators | ContainsComputedPropertyName | ContainsLexicalThisInComputedPropertyName,
-        ArrayLiteralOrCallOrNewExcludes = NodeExcludes | ContainsSpreadElementExpression,
-        VariableDeclarationListExcludes = NodeExcludes | ContainsBindingPattern,
-        ParameterExcludes = NodeExcludes | ContainsBindingPattern,
+        ObjectLiteralExcludes = NodeExcludes | ContainsDecorators | ContainsComputedPropertyName | ContainsLexicalThisInComputedPropertyName | ContainsObjectSpread,
+        ArrayLiteralOrCallOrNewExcludes = NodeExcludes | ContainsSpread,
+        VariableDeclarationListExcludes = NodeExcludes | ContainsBindingPattern | ContainsObjectRest,
+        ParameterExcludes = NodeExcludes,
+        CatchClauseExcludes = NodeExcludes | ContainsObjectRest,
+        BindingPatternExcludes = NodeExcludes | ContainsRest,
 
         // Masks
         // - Additional bitmasks
@@ -3541,45 +3664,70 @@ namespace ts {
 
     /* @internal */
     export interface EmitNode {
-        flags?: EmitFlags;
-        commentRange?: TextRange;
-        sourceMapRange?: TextRange;
-        tokenSourceMapRanges?: Map<TextRange>;
         annotatedNodes?: Node[];                // Tracks Parse-tree nodes with EmitNodes for eventual cleanup.
-        constantValue?: number;
+        flags?: EmitFlags;                      // Flags that customize emit
+        commentRange?: TextRange;               // The text range to use when emitting leading or trailing comments
+        sourceMapRange?: TextRange;             // The text range to use when emitting leading or trailing source mappings
+        tokenSourceMapRanges?: Map<TextRange>;  // The text range to use when emitting source mappings for tokens
+        constantValue?: number;                 // The constant value of an expression
+        externalHelpersModuleName?: Identifier; // The local name for an imported helpers module
+        helpers?: EmitHelper[];                 // Emit helpers for the node
     }
 
     /* @internal */
     export const enum EmitFlags {
-        EmitEmitHelpers = 1 << 0,                // Any emit helpers should be written to this node.
-        EmitExportStar = 1 << 1,                 // The export * helper should be written to this node.
-        EmitSuperHelper = 1 << 2,                // Emit the basic _super helper for async methods.
-        EmitAdvancedSuperHelper = 1 << 3,        // Emit the advanced _super helper for async methods.
-        UMDDefine = 1 << 4,                      // This node should be replaced with the UMD define helper.
-        SingleLine = 1 << 5,                     // The contents of this node should be emitted on a single line.
-        AdviseOnEmitNode = 1 << 6,               // The printer should invoke the onEmitNode callback when printing this node.
-        NoSubstitution = 1 << 7,                 // Disables further substitution of an expression.
-        CapturesThis = 1 << 8,                   // The function captures a lexical `this`
-        NoLeadingSourceMap = 1 << 9,             // Do not emit a leading source map location for this node.
-        NoTrailingSourceMap = 1 << 10,           // Do not emit a trailing source map location for this node.
+        SingleLine = 1 << 0,                     // The contents of this node should be emitted on a single line.
+        AdviseOnEmitNode = 1 << 1,               // The printer should invoke the onEmitNode callback when printing this node.
+        NoSubstitution = 1 << 2,                 // Disables further substitution of an expression.
+        CapturesThis = 1 << 3,                   // The function captures a lexical `this`
+        NoLeadingSourceMap = 1 << 4,             // Do not emit a leading source map location for this node.
+        NoTrailingSourceMap = 1 << 5,            // Do not emit a trailing source map location for this node.
         NoSourceMap = NoLeadingSourceMap | NoTrailingSourceMap, // Do not emit a source map location for this node.
-        NoNestedSourceMaps = 1 << 11,            // Do not emit source map locations for children of this node.
-        NoTokenLeadingSourceMaps = 1 << 12,      // Do not emit leading source map location for token nodes.
-        NoTokenTrailingSourceMaps = 1 << 13,     // Do not emit trailing source map location for token nodes.
+        NoNestedSourceMaps = 1 << 6,             // Do not emit source map locations for children of this node.
+        NoTokenLeadingSourceMaps = 1 << 7,       // Do not emit leading source map location for token nodes.
+        NoTokenTrailingSourceMaps = 1 << 8,      // Do not emit trailing source map location for token nodes.
         NoTokenSourceMaps = NoTokenLeadingSourceMaps | NoTokenTrailingSourceMaps, // Do not emit source map locations for tokens of this node.
-        NoLeadingComments = 1 << 14,             // Do not emit leading comments for this node.
-        NoTrailingComments = 1 << 15,            // Do not emit trailing comments for this node.
+        NoLeadingComments = 1 << 9,              // Do not emit leading comments for this node.
+        NoTrailingComments = 1 << 10,            // Do not emit trailing comments for this node.
         NoComments = NoLeadingComments | NoTrailingComments, // Do not emit comments for this node.
-        NoNestedComments = 1 << 16,
-        ExportName = 1 << 17,                    // Ensure an export prefix is added for an identifier that points to an exported declaration with a local name (see SymbolFlags.ExportHasLocal).
-        LocalName = 1 << 18,                     // Ensure an export prefix is not added for an identifier that points to an exported declaration.
-        Indented = 1 << 19,                      // Adds an explicit extra indentation level for class and function bodies when printing (used to match old emitter).
-        NoIndentation = 1 << 20,                 // Do not indent the node.
-        AsyncFunctionBody = 1 << 21,
-        ReuseTempVariableScope = 1 << 22,        // Reuse the existing temp variable scope during emit.
-        CustomPrologue = 1 << 23,                // Treat the statement as if it were a prologue directive (NOTE: Prologue directives are *not* transformed).
-        NoHoisting = 1 << 24,                    // Do not hoist this declaration in --module system
-        HasEndOfDeclarationMarker = 1 << 25,     // Declaration has an associated NotEmittedStatement to mark the end of the declaration
+        NoNestedComments = 1 << 11,
+        HelperName = 1 << 12,
+        ExportName = 1 << 13,                    // Ensure an export prefix is added for an identifier that points to an exported declaration with a local name (see SymbolFlags.ExportHasLocal).
+        LocalName = 1 << 14,                     // Ensure an export prefix is not added for an identifier that points to an exported declaration.
+        Indented = 1 << 15,                      // Adds an explicit extra indentation level for class and function bodies when printing (used to match old emitter).
+        NoIndentation = 1 << 16,                 // Do not indent the node.
+        AsyncFunctionBody = 1 << 17,
+        ReuseTempVariableScope = 1 << 18,        // Reuse the existing temp variable scope during emit.
+        CustomPrologue = 1 << 19,                // Treat the statement as if it were a prologue directive (NOTE: Prologue directives are *not* transformed).
+        NoHoisting = 1 << 20,                    // Do not hoist this declaration in --module system
+        HasEndOfDeclarationMarker = 1 << 21,     // Declaration has an associated NotEmittedStatement to mark the end of the declaration
+    }
+
+    /* @internal */
+    export interface EmitHelper {
+        readonly name: string;      // A unique name for this helper.
+        readonly scoped: boolean;   // Indicates whether ther helper MUST be emitted in the current scope.
+        readonly text: string;      // ES3-compatible raw script text.
+        readonly priority?: number; // Helpers with a higher priority are emitted earlier than other helpers on the node.
+    }
+
+    /**
+     * Used by the checker, this enum keeps track of external emit helpers that should be type
+     * checked.
+     */
+    /* @internal */
+    export const enum ExternalEmitHelpers {
+        Extends = 1 << 0,           // __extends (used by the ES2015 class transformation)
+        Assign = 1 << 1,            // __assign (used by Jsx and ESNext object spread transformations)
+        Rest = 1 << 2,              // __rest (used by ESNext object rest transformation)
+        Decorate = 1 << 3,          // __decorate (used by TypeScript decorators transformation)
+        Metadata = 1 << 4,          // __metadata (used by TypeScript decorators transformation)
+        Param = 1 << 5,             // __param (used by TypeScript decorators transformation)
+        Awaiter = 1 << 6,           // __awaiter (used by ES2017 async functions transformation)
+        Generator = 1 << 7,         // __generator (used by ES2015 generator transformation)
+
+        FirstEmitHelper = Extends,
+        LastEmitHelper = Generator
     }
 
     /* @internal */
@@ -3590,16 +3738,123 @@ namespace ts {
         Unspecified,        // Emitting an otherwise unspecified node
     }
 
-    /** Additional context provided to `visitEachChild` */
     /* @internal */
-    export interface LexicalEnvironment {
+    export interface EmitHost extends ScriptReferenceHost {
+        getSourceFiles(): SourceFile[];
+
+        /* @internal */
+        isSourceFileFromExternalLibrary(file: SourceFile): boolean;
+
+        getCommonSourceDirectory(): string;
+        getCanonicalFileName(fileName: string): string;
+        getNewLine(): string;
+
+        isEmitBlocked(emitFileName: string): boolean;
+
+        writeFile: WriteFileCallback;
+    }
+
+    /* @internal */
+    export interface TransformationContext {
+        getCompilerOptions(): CompilerOptions;
+        getEmitResolver(): EmitResolver;
+        getEmitHost(): EmitHost;
+
         /** Starts a new lexical environment. */
         startLexicalEnvironment(): void;
 
+        /** Suspends the current lexical environment, usually after visiting a parameter list. */
+        suspendLexicalEnvironment(): void;
+
+        /** Resumes a suspended lexical environment, usually before visiting a function body. */
+        resumeLexicalEnvironment(): void;
+
         /** Ends a lexical environment, returning any declarations. */
         endLexicalEnvironment(): Statement[];
+
+        /**
+         * Hoists a function declaration to the containing scope.
+         */
+        hoistFunctionDeclaration(node: FunctionDeclaration): void;
+
+        /**
+         * Hoists a variable declaration to the containing scope.
+         */
+        hoistVariableDeclaration(node: Identifier): void;
+
+        /**
+         * Records a request for a non-scoped emit helper in the current context.
+         */
+        requestEmitHelper(helper: EmitHelper): void;
+
+        /**
+         * Gets and resets the requested non-scoped emit helpers.
+         */
+        readEmitHelpers(): EmitHelper[] | undefined;
+
+        /**
+         * Enables expression substitutions in the pretty printer for the provided SyntaxKind.
+         */
+        enableSubstitution(kind: SyntaxKind): void;
+
+        /**
+         * Determines whether expression substitutions are enabled for the provided node.
+         */
+        isSubstitutionEnabled(node: Node): boolean;
+
+        /**
+         * Hook used by transformers to substitute expressions just before they
+         * are emitted by the pretty printer.
+         */
+        onSubstituteNode?: (emitContext: EmitContext, node: Node) => Node;
+
+        /**
+         * Enables before/after emit notifications in the pretty printer for the provided
+         * SyntaxKind.
+         */
+        enableEmitNotification(kind: SyntaxKind): void;
+
+        /**
+         * Determines whether before/after emit notifications should be raised in the pretty
+         * printer when it emits a node.
+         */
+        isEmitNotificationEnabled(node: Node): boolean;
+
+        /**
+         * Hook used to allow transformers to capture state before or after
+         * the printer emits a node.
+         */
+        onEmitNode?: (emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void) => void;
     }
 
+    /* @internal */
+    export interface TransformationResult {
+        /**
+         * Gets the transformed source files.
+         */
+        transformed: SourceFile[];
+
+        /**
+         * Emits the substitute for a node, if one is available; otherwise, emits the node.
+         *
+         * @param emitContext The current emit context.
+         * @param node The node to substitute.
+         * @param emitCallback A callback used to emit the node or its substitute.
+         */
+        emitNodeWithSubstitution(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void;
+
+        /**
+         * Emits a node with possible notification.
+         *
+         * @param emitContext The current emit context.
+         * @param node The node to emit.
+         * @param emitCallback A callback used to emit the node.
+         */
+        emitNodeWithNotification(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void;
+    }
+
+    /* @internal */
+    export type Transformer = (context: TransformationContext) => (node: SourceFile) => SourceFile;
 
     export interface TextSpan {
         start: number;

src/compiler/visitor.ts

@@ -99,20 +99,26 @@ namespace ts {
         return node ? f(initial, node) : initial;
     }
 
+    function reduceNodeArray<T>(nodes: Node[], f: (memo: T, nodes: Node[]) => T, initial: T) {
+        return nodes ? f(initial, nodes) : initial;
+    }
+
     /**
      * Similar to `reduceLeft`, performs a reduction against each child of a node.
      * NOTE: Unlike `forEachChild`, this does *not* visit every node. Only nodes added to the
      *       `nodeEdgeTraversalMap` above will be visited.
      *
      * @param node The node containing the children to reduce.
-     * @param f The callback function
      * @param initial The initial value to supply to the reduction.
+     * @param f The callback function
      */
-    export function reduceEachChild<T>(node: Node, f: (memo: T, node: Node) => T, initial: T): T {
+    export function reduceEachChild<T>(node: Node, initial: T, cbNode: (memo: T, node: Node) => T, cbNodeArray?: (memo: T, nodes: Node[]) => T): T {
         if (node === undefined) {
             return initial;
         }
 
+        const reduceNodes: (nodes: Node[], f: (memo: T, node: Node | Node[]) => T, initial: T) => T = cbNodeArray ? reduceNodeArray : reduceLeft;
+        const cbNodes = cbNodeArray || cbNode;
         const kind = node.kind;
 
         // No need to visit nodes with no children.
@@ -138,127 +144,127 @@ namespace ts {
 
             // Names
             case SyntaxKind.ComputedPropertyName:
-                result = reduceNode((<ComputedPropertyName>node).expression, f, result);
+                result = reduceNode((<ComputedPropertyName>node).expression, cbNode, result);
                 break;
 
             // Signature elements
             case SyntaxKind.Parameter:
-                result = reduceLeft((<ParameterDeclaration>node).decorators, f, result);
-                result = reduceLeft((<ParameterDeclaration>node).modifiers, f, result);
-                result = reduceNode((<ParameterDeclaration>node).name, f, result);
-                result = reduceNode((<ParameterDeclaration>node).type, f, result);
-                result = reduceNode((<ParameterDeclaration>node).initializer, f, result);
+                result = reduceNodes((<ParameterDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<ParameterDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<ParameterDeclaration>node).name, cbNode, result);
+                result = reduceNode((<ParameterDeclaration>node).type, cbNode, result);
+                result = reduceNode((<ParameterDeclaration>node).initializer, cbNode, result);
                 break;
 
             case SyntaxKind.Decorator:
-                result = reduceNode((<Decorator>node).expression, f, result);
+                result = reduceNode((<Decorator>node).expression, cbNode, result);
                 break;
 
             // Type member
             case SyntaxKind.PropertyDeclaration:
-                result = reduceLeft((<PropertyDeclaration>node).decorators, f, result);
-                result = reduceLeft((<PropertyDeclaration>node).modifiers, f, result);
-                result = reduceNode((<PropertyDeclaration>node).name, f, result);
-                result = reduceNode((<PropertyDeclaration>node).type, f, result);
-                result = reduceNode((<PropertyDeclaration>node).initializer, f, result);
+                result = reduceNodes((<PropertyDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<PropertyDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<PropertyDeclaration>node).name, cbNode, result);
+                result = reduceNode((<PropertyDeclaration>node).type, cbNode, result);
+                result = reduceNode((<PropertyDeclaration>node).initializer, cbNode, result);
                 break;
 
             case SyntaxKind.MethodDeclaration:
-                result = reduceLeft((<MethodDeclaration>node).decorators, f, result);
-                result = reduceLeft((<MethodDeclaration>node).modifiers, f, result);
-                result = reduceNode((<MethodDeclaration>node).name, f, result);
-                result = reduceLeft((<MethodDeclaration>node).typeParameters, f, result);
-                result = reduceLeft((<MethodDeclaration>node).parameters, f, result);
-                result = reduceNode((<MethodDeclaration>node).type, f, result);
-                result = reduceNode((<MethodDeclaration>node).body, f, result);
+                result = reduceNodes((<MethodDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<MethodDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<MethodDeclaration>node).name, cbNode, result);
+                result = reduceNodes((<MethodDeclaration>node).typeParameters, cbNodes, result);
+                result = reduceNodes((<MethodDeclaration>node).parameters, cbNodes, result);
+                result = reduceNode((<MethodDeclaration>node).type, cbNode, result);
+                result = reduceNode((<MethodDeclaration>node).body, cbNode, result);
                 break;
 
             case SyntaxKind.Constructor:
-                result = reduceLeft((<ConstructorDeclaration>node).modifiers, f, result);
-                result = reduceLeft((<ConstructorDeclaration>node).parameters, f, result);
-                result = reduceNode((<ConstructorDeclaration>node).body, f, result);
+                result = reduceNodes((<ConstructorDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNodes((<ConstructorDeclaration>node).parameters, cbNodes, result);
+                result = reduceNode((<ConstructorDeclaration>node).body, cbNode, result);
                 break;
 
             case SyntaxKind.GetAccessor:
-                result = reduceLeft((<GetAccessorDeclaration>node).decorators, f, result);
-                result = reduceLeft((<GetAccessorDeclaration>node).modifiers, f, result);
-                result = reduceNode((<GetAccessorDeclaration>node).name, f, result);
-                result = reduceLeft((<GetAccessorDeclaration>node).parameters, f, result);
-                result = reduceNode((<GetAccessorDeclaration>node).type, f, result);
-                result = reduceNode((<GetAccessorDeclaration>node).body, f, result);
+                result = reduceNodes((<GetAccessorDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<GetAccessorDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<GetAccessorDeclaration>node).name, cbNode, result);
+                result = reduceNodes((<GetAccessorDeclaration>node).parameters, cbNodes, result);
+                result = reduceNode((<GetAccessorDeclaration>node).type, cbNode, result);
+                result = reduceNode((<GetAccessorDeclaration>node).body, cbNode, result);
                 break;
 
             case SyntaxKind.SetAccessor:
-                result = reduceLeft((<GetAccessorDeclaration>node).decorators, f, result);
-                result = reduceLeft((<GetAccessorDeclaration>node).modifiers, f, result);
-                result = reduceNode((<GetAccessorDeclaration>node).name, f, result);
-                result = reduceLeft((<GetAccessorDeclaration>node).parameters, f, result);
-                result = reduceNode((<GetAccessorDeclaration>node).body, f, result);
+                result = reduceNodes((<GetAccessorDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<GetAccessorDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<GetAccessorDeclaration>node).name, cbNode, result);
+                result = reduceNodes((<GetAccessorDeclaration>node).parameters, cbNodes, result);
+                result = reduceNode((<GetAccessorDeclaration>node).body, cbNode, result);
                 break;
 
             // Binding patterns
             case SyntaxKind.ObjectBindingPattern:
             case SyntaxKind.ArrayBindingPattern:
-                result = reduceLeft((<BindingPattern>node).elements, f, result);
+                result = reduceNodes((<BindingPattern>node).elements, cbNodes, result);
                 break;
 
             case SyntaxKind.BindingElement:
-                result = reduceNode((<BindingElement>node).propertyName, f, result);
-                result = reduceNode((<BindingElement>node).name, f, result);
-                result = reduceNode((<BindingElement>node).initializer, f, result);
+                result = reduceNode((<BindingElement>node).propertyName, cbNode, result);
+                result = reduceNode((<BindingElement>node).name, cbNode, result);
+                result = reduceNode((<BindingElement>node).initializer, cbNode, result);
                 break;
 
             // Expression
             case SyntaxKind.ArrayLiteralExpression:
-                result = reduceLeft((<ArrayLiteralExpression>node).elements, f, result);
+                result = reduceNodes((<ArrayLiteralExpression>node).elements, cbNodes, result);
                 break;
 
             case SyntaxKind.ObjectLiteralExpression:
-                result = reduceLeft((<ObjectLiteralExpression>node).properties, f, result);
+                result = reduceNodes((<ObjectLiteralExpression>node).properties, cbNodes, result);
                 break;
 
             case SyntaxKind.PropertyAccessExpression:
-                result = reduceNode((<PropertyAccessExpression>node).expression, f, result);
-                result = reduceNode((<PropertyAccessExpression>node).name, f, result);
+                result = reduceNode((<PropertyAccessExpression>node).expression, cbNode, result);
+                result = reduceNode((<PropertyAccessExpression>node).name, cbNode, result);
                 break;
 
             case SyntaxKind.ElementAccessExpression:
-                result = reduceNode((<ElementAccessExpression>node).expression, f, result);
-                result = reduceNode((<ElementAccessExpression>node).argumentExpression, f, result);
+                result = reduceNode((<ElementAccessExpression>node).expression, cbNode, result);
+                result = reduceNode((<ElementAccessExpression>node).argumentExpression, cbNode, result);
                 break;
 
             case SyntaxKind.CallExpression:
-                result = reduceNode((<CallExpression>node).expression, f, result);
-                result = reduceLeft((<CallExpression>node).typeArguments, f, result);
-                result = reduceLeft((<CallExpression>node).arguments, f, result);
+                result = reduceNode((<CallExpression>node).expression, cbNode, result);
+                result = reduceNodes((<CallExpression>node).typeArguments, cbNodes, result);
+                result = reduceNodes((<CallExpression>node).arguments, cbNodes, result);
                 break;
 
             case SyntaxKind.NewExpression:
-                result = reduceNode((<NewExpression>node).expression, f, result);
-                result = reduceLeft((<NewExpression>node).typeArguments, f, result);
-                result = reduceLeft((<NewExpression>node).arguments, f, result);
+                result = reduceNode((<NewExpression>node).expression, cbNode, result);
+                result = reduceNodes((<NewExpression>node).typeArguments, cbNodes, result);
+                result = reduceNodes((<NewExpression>node).arguments, cbNodes, result);
                 break;
 
             case SyntaxKind.TaggedTemplateExpression:
-                result = reduceNode((<TaggedTemplateExpression>node).tag, f, result);
-                result = reduceNode((<TaggedTemplateExpression>node).template, f, result);
+                result = reduceNode((<TaggedTemplateExpression>node).tag, cbNode, result);
+                result = reduceNode((<TaggedTemplateExpression>node).template, cbNode, result);
                 break;
 
             case SyntaxKind.FunctionExpression:
-                result = reduceLeft((<FunctionExpression>node).modifiers, f, result);
-                result = reduceNode((<FunctionExpression>node).name, f, result);
-                result = reduceLeft((<FunctionExpression>node).typeParameters, f, result);
-                result = reduceLeft((<FunctionExpression>node).parameters, f, result);
-                result = reduceNode((<FunctionExpression>node).type, f, result);
-                result = reduceNode((<FunctionExpression>node).body, f, result);
+                result = reduceNodes((<FunctionExpression>node).modifiers, cbNodes, result);
+                result = reduceNode((<FunctionExpression>node).name, cbNode, result);
+                result = reduceNodes((<FunctionExpression>node).typeParameters, cbNodes, result);
+                result = reduceNodes((<FunctionExpression>node).parameters, cbNodes, result);
+                result = reduceNode((<FunctionExpression>node).type, cbNode, result);
+                result = reduceNode((<FunctionExpression>node).body, cbNode, result);
                 break;
 
             case SyntaxKind.ArrowFunction:
-                result = reduceLeft((<ArrowFunction>node).modifiers, f, result);
-                result = reduceLeft((<ArrowFunction>node).typeParameters, f, result);
-                result = reduceLeft((<ArrowFunction>node).parameters, f, result);
-                result = reduceNode((<ArrowFunction>node).type, f, result);
-                result = reduceNode((<ArrowFunction>node).body, f, result);
+                result = reduceNodes((<ArrowFunction>node).modifiers, cbNodes, result);
+                result = reduceNodes((<ArrowFunction>node).typeParameters, cbNodes, result);
+                result = reduceNodes((<ArrowFunction>node).parameters, cbNodes, result);
+                result = reduceNode((<ArrowFunction>node).type, cbNode, result);
+                result = reduceNode((<ArrowFunction>node).body, cbNode, result);
                 break;
 
             case SyntaxKind.ParenthesizedExpression:
@@ -267,256 +273,260 @@ namespace ts {
             case SyntaxKind.VoidExpression:
             case SyntaxKind.AwaitExpression:
             case SyntaxKind.YieldExpression:
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadElement:
             case SyntaxKind.NonNullExpression:
-                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadElementExpression | NonNullExpression>node).expression, f, result);
+                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadElement | NonNullExpression>node).expression, cbNode, result);
                 break;
 
             case SyntaxKind.PrefixUnaryExpression:
             case SyntaxKind.PostfixUnaryExpression:
-                result = reduceNode((<PrefixUnaryExpression | PostfixUnaryExpression>node).operand, f, result);
+                result = reduceNode((<PrefixUnaryExpression | PostfixUnaryExpression>node).operand, cbNode, result);
                 break;
 
             case SyntaxKind.BinaryExpression:
-                result = reduceNode((<BinaryExpression>node).left, f, result);
-                result = reduceNode((<BinaryExpression>node).right, f, result);
+                result = reduceNode((<BinaryExpression>node).left, cbNode, result);
+                result = reduceNode((<BinaryExpression>node).right, cbNode, result);
                 break;
 
             case SyntaxKind.ConditionalExpression:
-                result = reduceNode((<ConditionalExpression>node).condition, f, result);
-                result = reduceNode((<ConditionalExpression>node).whenTrue, f, result);
-                result = reduceNode((<ConditionalExpression>node).whenFalse, f, result);
+                result = reduceNode((<ConditionalExpression>node).condition, cbNode, result);
+                result = reduceNode((<ConditionalExpression>node).whenTrue, cbNode, result);
+                result = reduceNode((<ConditionalExpression>node).whenFalse, cbNode, result);
                 break;
 
             case SyntaxKind.TemplateExpression:
-                result = reduceNode((<TemplateExpression>node).head, f, result);
-                result = reduceLeft((<TemplateExpression>node).templateSpans, f, result);
+                result = reduceNode((<TemplateExpression>node).head, cbNode, result);
+                result = reduceNodes((<TemplateExpression>node).templateSpans, cbNodes, result);
                 break;
 
             case SyntaxKind.ClassExpression:
-                result = reduceLeft((<ClassExpression>node).modifiers, f, result);
-                result = reduceNode((<ClassExpression>node).name, f, result);
-                result = reduceLeft((<ClassExpression>node).typeParameters, f, result);
-                result = reduceLeft((<ClassExpression>node).heritageClauses, f, result);
-                result = reduceLeft((<ClassExpression>node).members, f, result);
+                result = reduceNodes((<ClassExpression>node).modifiers, cbNodes, result);
+                result = reduceNode((<ClassExpression>node).name, cbNode, result);
+                result = reduceNodes((<ClassExpression>node).typeParameters, cbNodes, result);
+                result = reduceNodes((<ClassExpression>node).heritageClauses, cbNodes, result);
+                result = reduceNodes((<ClassExpression>node).members, cbNodes, result);
                 break;
 
             case SyntaxKind.ExpressionWithTypeArguments:
-                result = reduceNode((<ExpressionWithTypeArguments>node).expression, f, result);
-                result = reduceLeft((<ExpressionWithTypeArguments>node).typeArguments, f, result);
+                result = reduceNode((<ExpressionWithTypeArguments>node).expression, cbNode, result);
+                result = reduceNodes((<ExpressionWithTypeArguments>node).typeArguments, cbNodes, result);
                 break;
 
             // Misc
             case SyntaxKind.TemplateSpan:
-                result = reduceNode((<TemplateSpan>node).expression, f, result);
-                result = reduceNode((<TemplateSpan>node).literal, f, result);
+                result = reduceNode((<TemplateSpan>node).expression, cbNode, result);
+                result = reduceNode((<TemplateSpan>node).literal, cbNode, result);
                 break;
 
             // Element
             case SyntaxKind.Block:
-                result = reduceLeft((<Block>node).statements, f, result);
+                result = reduceNodes((<Block>node).statements, cbNodes, result);
                 break;
 
             case SyntaxKind.VariableStatement:
-                result = reduceLeft((<VariableStatement>node).modifiers, f, result);
-                result = reduceNode((<VariableStatement>node).declarationList, f, result);
+                result = reduceNodes((<VariableStatement>node).modifiers, cbNodes, result);
+                result = reduceNode((<VariableStatement>node).declarationList, cbNode, result);
                 break;
 
             case SyntaxKind.ExpressionStatement:
-                result = reduceNode((<ExpressionStatement>node).expression, f, result);
+                result = reduceNode((<ExpressionStatement>node).expression, cbNode, result);
                 break;
 
             case SyntaxKind.IfStatement:
-                result = reduceNode((<IfStatement>node).expression, f, result);
-                result = reduceNode((<IfStatement>node).thenStatement, f, result);
-                result = reduceNode((<IfStatement>node).elseStatement, f, result);
+                result = reduceNode((<IfStatement>node).expression, cbNode, result);
+                result = reduceNode((<IfStatement>node).thenStatement, cbNode, result);
+                result = reduceNode((<IfStatement>node).elseStatement, cbNode, result);
                 break;
 
             case SyntaxKind.DoStatement:
-                result = reduceNode((<DoStatement>node).statement, f, result);
-                result = reduceNode((<DoStatement>node).expression, f, result);
+                result = reduceNode((<DoStatement>node).statement, cbNode, result);
+                result = reduceNode((<DoStatement>node).expression, cbNode, result);
                 break;
 
             case SyntaxKind.WhileStatement:
             case SyntaxKind.WithStatement:
-                result = reduceNode((<WhileStatement | WithStatement>node).expression, f, result);
-                result = reduceNode((<WhileStatement | WithStatement>node).statement, f, result);
+                result = reduceNode((<WhileStatement | WithStatement>node).expression, cbNode, result);
+                result = reduceNode((<WhileStatement | WithStatement>node).statement, cbNode, result);
                 break;
 
             case SyntaxKind.ForStatement:
-                result = reduceNode((<ForStatement>node).initializer, f, result);
-                result = reduceNode((<ForStatement>node).condition, f, result);
-                result = reduceNode((<ForStatement>node).incrementor, f, result);
-                result = reduceNode((<ForStatement>node).statement, f, result);
+                result = reduceNode((<ForStatement>node).initializer, cbNode, result);
+                result = reduceNode((<ForStatement>node).condition, cbNode, result);
+                result = reduceNode((<ForStatement>node).incrementor, cbNode, result);
+                result = reduceNode((<ForStatement>node).statement, cbNode, result);
                 break;
 
             case SyntaxKind.ForInStatement:
             case SyntaxKind.ForOfStatement:
-                result = reduceNode((<ForInStatement | ForOfStatement>node).initializer, f, result);
-                result = reduceNode((<ForInStatement | ForOfStatement>node).expression, f, result);
-                result = reduceNode((<ForInStatement | ForOfStatement>node).statement, f, result);
+                result = reduceNode((<ForInStatement | ForOfStatement>node).initializer, cbNode, result);
+                result = reduceNode((<ForInStatement | ForOfStatement>node).expression, cbNode, result);
+                result = reduceNode((<ForInStatement | ForOfStatement>node).statement, cbNode, result);
                 break;
 
             case SyntaxKind.ReturnStatement:
             case SyntaxKind.ThrowStatement:
-                result = reduceNode((<ReturnStatement>node).expression, f, result);
+                result = reduceNode((<ReturnStatement>node).expression, cbNode, result);
                 break;
 
             case SyntaxKind.SwitchStatement:
-                result = reduceNode((<SwitchStatement>node).expression, f, result);
-                result = reduceNode((<SwitchStatement>node).caseBlock, f, result);
+                result = reduceNode((<SwitchStatement>node).expression, cbNode, result);
+                result = reduceNode((<SwitchStatement>node).caseBlock, cbNode, result);
                 break;
 
             case SyntaxKind.LabeledStatement:
-                result = reduceNode((<LabeledStatement>node).label, f, result);
-                result = reduceNode((<LabeledStatement>node).statement, f, result);
+                result = reduceNode((<LabeledStatement>node).label, cbNode, result);
+                result = reduceNode((<LabeledStatement>node).statement, cbNode, result);
                 break;
 
             case SyntaxKind.TryStatement:
-                result = reduceNode((<TryStatement>node).tryBlock, f, result);
-                result = reduceNode((<TryStatement>node).catchClause, f, result);
-                result = reduceNode((<TryStatement>node).finallyBlock, f, result);
+                result = reduceNode((<TryStatement>node).tryBlock, cbNode, result);
+                result = reduceNode((<TryStatement>node).catchClause, cbNode, result);
+                result = reduceNode((<TryStatement>node).finallyBlock, cbNode, result);
                 break;
 
             case SyntaxKind.VariableDeclaration:
-                result = reduceNode((<VariableDeclaration>node).name, f, result);
-                result = reduceNode((<VariableDeclaration>node).type, f, result);
-                result = reduceNode((<VariableDeclaration>node).initializer, f, result);
+                result = reduceNode((<VariableDeclaration>node).name, cbNode, result);
+                result = reduceNode((<VariableDeclaration>node).type, cbNode, result);
+                result = reduceNode((<VariableDeclaration>node).initializer, cbNode, result);
                 break;
 
             case SyntaxKind.VariableDeclarationList:
-                result = reduceLeft((<VariableDeclarationList>node).declarations, f, result);
+                result = reduceNodes((<VariableDeclarationList>node).declarations, cbNodes, result);
                 break;
 
             case SyntaxKind.FunctionDeclaration:
-                result = reduceLeft((<FunctionDeclaration>node).decorators, f, result);
-                result = reduceLeft((<FunctionDeclaration>node).modifiers, f, result);
-                result = reduceNode((<FunctionDeclaration>node).name, f, result);
-                result = reduceLeft((<FunctionDeclaration>node).typeParameters, f, result);
-                result = reduceLeft((<FunctionDeclaration>node).parameters, f, result);
-                result = reduceNode((<FunctionDeclaration>node).type, f, result);
-                result = reduceNode((<FunctionDeclaration>node).body, f, result);
+                result = reduceNodes((<FunctionDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<FunctionDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<FunctionDeclaration>node).name, cbNode, result);
+                result = reduceNodes((<FunctionDeclaration>node).typeParameters, cbNodes, result);
+                result = reduceNodes((<FunctionDeclaration>node).parameters, cbNodes, result);
+                result = reduceNode((<FunctionDeclaration>node).type, cbNode, result);
+                result = reduceNode((<FunctionDeclaration>node).body, cbNode, result);
                 break;
 
             case SyntaxKind.ClassDeclaration:
-                result = reduceLeft((<ClassDeclaration>node).decorators, f, result);
-                result = reduceLeft((<ClassDeclaration>node).modifiers, f, result);
-                result = reduceNode((<ClassDeclaration>node).name, f, result);
-                result = reduceLeft((<ClassDeclaration>node).typeParameters, f, result);
-                result = reduceLeft((<ClassDeclaration>node).heritageClauses, f, result);
-                result = reduceLeft((<ClassDeclaration>node).members, f, result);
+                result = reduceNodes((<ClassDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<ClassDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<ClassDeclaration>node).name, cbNode, result);
+                result = reduceNodes((<ClassDeclaration>node).typeParameters, cbNodes, result);
+                result = reduceNodes((<ClassDeclaration>node).heritageClauses, cbNodes, result);
+                result = reduceNodes((<ClassDeclaration>node).members, cbNodes, result);
                 break;
 
             case SyntaxKind.CaseBlock:
-                result = reduceLeft((<CaseBlock>node).clauses, f, result);
+                result = reduceNodes((<CaseBlock>node).clauses, cbNodes, result);
                 break;
 
             case SyntaxKind.ImportDeclaration:
-                result = reduceLeft((<ImportDeclaration>node).decorators, f, result);
-                result = reduceLeft((<ImportDeclaration>node).modifiers, f, result);
-                result = reduceNode((<ImportDeclaration>node).importClause, f, result);
-                result = reduceNode((<ImportDeclaration>node).moduleSpecifier, f, result);
+                result = reduceNodes((<ImportDeclaration>node).decorators, cbNodes, result);
+                result = reduceNodes((<ImportDeclaration>node).modifiers, cbNodes, result);
+                result = reduceNode((<ImportDeclaration>node).importClause, cbNode, result);
+                result = reduceNode((<ImportDeclaration>node).moduleSpecifier, cbNode, result);
                 break;
 
             case SyntaxKind.ImportClause:
-                result = reduceNode((<ImportClause>node).name, f, result);
-                result = reduceNode((<ImportClause>node).namedBindings, f, result);
+                result = reduceNode((<ImportClause>node).name, cbNode, result);
+                result = reduceNode((<ImportClause>node).namedBindings, cbNode, result);
                 break;
 
             case SyntaxKind.NamespaceImport:
-                result = reduceNode((<NamespaceImport>node).name, f, result);
+                result = reduceNode((<NamespaceImport>node).name, cbNode, result);
                 break;
 
             case SyntaxKind.NamedImports:
             case SyntaxKind.NamedExports:
-                result = reduceLeft((<NamedImports | NamedExports>node).elements, f, result);
+                result = reduceNodes((<NamedImports | NamedExports>node).elements, cbNodes, result);
                 break;
 
             case SyntaxKind.ImportSpecifier:
             case SyntaxKind.ExportSpecifier:
-                result = reduceNode((<ImportSpecifier | ExportSpecifier>node).propertyName, f, result);
-                result = reduceNode((<ImportSpecifier | ExportSpecifier>node).name, f, result);
+                result = reduceNode((<ImportSpecifier | ExportSpecifier>node).propertyName, cbNode, result);
+                result = reduceNode((<ImportSpecifier | ExportSpecifier>node).name, cbNode, result);
                 break;
 
             case SyntaxKind.ExportAssignment:
-                result = reduceLeft((<ExportAssignment>node).decorators, f, result);
-                result = reduceLeft((<ExportAssignment>node).modifiers, f, result);
-                result = reduceNode((<ExportAssignment>node).expression, f, result);
+                result = reduceLeft((<ExportAssignment>node).decorators, cbNode, result);
+                result = reduceLeft((<ExportAssignment>node).modifiers, cbNode, result);
+                result = reduceNode((<ExportAssignment>node).expression, cbNode, result);
                 break;
 
             case SyntaxKind.ExportDeclaration:
-                result = reduceLeft((<ExportDeclaration>node).decorators, f, result);
-                result = reduceLeft((<ExportDeclaration>node).modifiers, f, result);
-                result = reduceNode((<ExportDeclaration>node).exportClause, f, result);
-                result = reduceNode((<ExportDeclaration>node).moduleSpecifier, f, result);
+                result = reduceLeft((<ExportDeclaration>node).decorators, cbNode, result);
+                result = reduceLeft((<ExportDeclaration>node).modifiers, cbNode, result);
+                result = reduceNode((<ExportDeclaration>node).exportClause, cbNode, result);
+                result = reduceNode((<ExportDeclaration>node).moduleSpecifier, cbNode, result);
                 break;
 
             // JSX
             case SyntaxKind.JsxElement:
-                result = reduceNode((<JsxElement>node).openingElement, f, result);
-                result = reduceLeft((<JsxElement>node).children, f, result);
-                result = reduceNode((<JsxElement>node).closingElement, f, result);
+                result = reduceNode((<JsxElement>node).openingElement, cbNode, result);
+                result = reduceLeft((<JsxElement>node).children, cbNode, result);
+                result = reduceNode((<JsxElement>node).closingElement, cbNode, result);
                 break;
 
             case SyntaxKind.JsxSelfClosingElement:
             case SyntaxKind.JsxOpeningElement:
-                result = reduceNode((<JsxSelfClosingElement | JsxOpeningElement>node).tagName, f, result);
-                result = reduceLeft((<JsxSelfClosingElement | JsxOpeningElement>node).attributes, f, result);
+                result = reduceNode((<JsxSelfClosingElement | JsxOpeningElement>node).tagName, cbNode, result);
+                result = reduceNodes((<JsxSelfClosingElement | JsxOpeningElement>node).attributes, cbNodes, result);
                 break;
 
             case SyntaxKind.JsxClosingElement:
-                result = reduceNode((<JsxClosingElement>node).tagName, f, result);
+                result = reduceNode((<JsxClosingElement>node).tagName, cbNode, result);
                 break;
 
             case SyntaxKind.JsxAttribute:
-                result = reduceNode((<JsxAttribute>node).name, f, result);
-                result = reduceNode((<JsxAttribute>node).initializer, f, result);
+                result = reduceNode((<JsxAttribute>node).name, cbNode, result);
+                result = reduceNode((<JsxAttribute>node).initializer, cbNode, result);
                 break;
 
             case SyntaxKind.JsxSpreadAttribute:
-                result = reduceNode((<JsxSpreadAttribute>node).expression, f, result);
+                result = reduceNode((<JsxSpreadAttribute>node).expression, cbNode, result);
                 break;
 
             case SyntaxKind.JsxExpression:
-                result = reduceNode((<JsxExpression>node).expression, f, result);
+                result = reduceNode((<JsxExpression>node).expression, cbNode, result);
                 break;
 
             // Clauses
             case SyntaxKind.CaseClause:
-                result = reduceNode((<CaseClause>node).expression, f, result);
+                result = reduceNode((<CaseClause>node).expression, cbNode, result);
                 // fall-through
 
             case SyntaxKind.DefaultClause:
-                result = reduceLeft((<CaseClause | DefaultClause>node).statements, f, result);
+                result = reduceNodes((<CaseClause | DefaultClause>node).statements, cbNodes, result);
                 break;
 
             case SyntaxKind.HeritageClause:
-                result = reduceLeft((<HeritageClause>node).types, f, result);
+                result = reduceNodes((<HeritageClause>node).types, cbNodes, result);
                 break;
 
             case SyntaxKind.CatchClause:
-                result = reduceNode((<CatchClause>node).variableDeclaration, f, result);
-                result = reduceNode((<CatchClause>node).block, f, result);
+                result = reduceNode((<CatchClause>node).variableDeclaration, cbNode, result);
+                result = reduceNode((<CatchClause>node).block, cbNode, result);
                 break;
 
             // Property assignments
             case SyntaxKind.PropertyAssignment:
-                result = reduceNode((<PropertyAssignment>node).name, f, result);
-                result = reduceNode((<PropertyAssignment>node).initializer, f, result);
+                result = reduceNode((<PropertyAssignment>node).name, cbNode, result);
+                result = reduceNode((<PropertyAssignment>node).initializer, cbNode, result);
                 break;
 
             case SyntaxKind.ShorthandPropertyAssignment:
-                result = reduceNode((<ShorthandPropertyAssignment>node).name, f, result);
-                result = reduceNode((<ShorthandPropertyAssignment>node).objectAssignmentInitializer, f, result);
+                result = reduceNode((<ShorthandPropertyAssignment>node).name, cbNode, result);
+                result = reduceNode((<ShorthandPropertyAssignment>node).objectAssignmentInitializer, cbNode, result);
+                break;
+
+            case SyntaxKind.SpreadAssignment:
+                result = reduceNode((node as SpreadAssignment).expression, cbNode, result);
                 break;
 
             // Top-level nodes
             case SyntaxKind.SourceFile:
-                result = reduceLeft((<SourceFile>node).statements, f, result);
+                result = reduceNodes((<SourceFile>node).statements, cbNodes, result);
                 break;
 
             case SyntaxKind.PartiallyEmittedExpression:
-                result = reduceNode((<PartiallyEmittedExpression>node).expression, f, result);
+                result = reduceNode((<PartiallyEmittedExpression>node).expression, cbNode, result);
                 break;
 
             default:
@@ -526,8 +536,8 @@ namespace ts {
                         const value = (<MapLike<any>>node)[edge.name];
                         if (value !== undefined) {
                             result = isArray(value)
-                                ? reduceLeft(<NodeArray<Node>>value, f, result)
-                                : f(result, <Node>value);
+                                ? reduceNodes(<NodeArray<Node>>value, cbNodes, result)
+                                : cbNode(result, <Node>value);
                         }
                     }
                 }
@@ -549,8 +559,8 @@ namespace ts {
     export function visitNode<T extends Node>(node: T, visitor: (node: Node) => VisitResult<Node>, test: (node: Node) => boolean, optional?: boolean, lift?: (node: NodeArray<Node>) => T): T;
     export function visitNode<T extends Node>(node: T, visitor: (node: Node) => VisitResult<Node>, test: (node: Node) => boolean, optional: boolean, lift: (node: NodeArray<Node>) => T, parenthesize: (node: Node, parentNode: Node) => Node, parentNode: Node): T;
     export function visitNode(node: Node, visitor: (node: Node) => VisitResult<Node>, test: (node: Node) => boolean, optional?: boolean, lift?: (node: Node[]) => Node, parenthesize?: (node: Node, parentNode: Node) => Node, parentNode?: Node): Node {
-        if (node === undefined) {
-            return undefined;
+        if (node === undefined || visitor === undefined) {
+            return node;
         }
 
         aggregateTransformFlags(node);
@@ -655,6 +665,53 @@ namespace ts {
         return updated || nodes;
     }
 
+    /**
+     * Starts a new lexical environment and visits a statement list, ending the lexical environment
+     * and merging hoisted declarations upon completion.
+     */
+    export function visitLexicalEnvironment(statements: NodeArray<Statement>, visitor: (node: Node) => VisitResult<Node>, context: TransformationContext, start?: number, ensureUseStrict?: boolean) {
+        context.startLexicalEnvironment();
+        statements = visitNodes(statements, visitor, isStatement, start);
+        if (ensureUseStrict && !startsWithUseStrict(statements)) {
+            statements = createNodeArray([createStatement(createLiteral("use strict")), ...statements], statements);
+        }
+        const declarations = context.endLexicalEnvironment();
+        return createNodeArray(concatenate(statements, declarations), statements);
+    }
+
+    /**
+     * Starts a new lexical environment and visits a parameter list, suspending the lexical
+     * environment upon completion.
+     */
+    export function visitParameterList(nodes: NodeArray<ParameterDeclaration>, visitor: (node: Node) => VisitResult<Node>, context: TransformationContext) {
+        context.startLexicalEnvironment();
+        const updated = visitNodes(nodes, visitor, isParameterDeclaration);
+        context.suspendLexicalEnvironment();
+        return updated;
+    }
+
+    /**
+     * Resumes a suspended lexical environment and visits a function body, ending the lexical
+     * environment and merging hoisted declarations upon completion.
+     */
+    export function visitFunctionBody(node: FunctionBody, visitor: (node: Node) => VisitResult<Node>, context: TransformationContext): FunctionBody;
+    /**
+     * Resumes a suspended lexical environment and visits a concise body, ending the lexical
+     * environment and merging hoisted declarations upon completion.
+     */
+    export function visitFunctionBody(node: ConciseBody, visitor: (node: Node) => VisitResult<Node>, context: TransformationContext): ConciseBody;
+    export function visitFunctionBody(node: ConciseBody, visitor: (node: Node) => VisitResult<Node>, context: TransformationContext): ConciseBody {
+        context.resumeLexicalEnvironment();
+        const updated = visitNode(node, visitor, isConciseBody);
+        const declarations = context.endLexicalEnvironment();
+        if (some(declarations)) {
+            const block = convertToFunctionBody(updated);
+            const statements = mergeLexicalEnvironment(block.statements, declarations);
+            return updateBlock(block, statements);
+        }
+        return updated;
+    }
+
     /**
      * Visits each child of a Node using the supplied visitor, possibly returning a new Node of the same kind in its place.
      *
@@ -662,8 +719,8 @@ namespace ts {
      * @param visitor The callback used to visit each child.
      * @param context A lexical environment context for the visitor.
      */
-    export function visitEachChild<T extends Node>(node: T, visitor: (node: Node) => VisitResult<Node>, context: LexicalEnvironment): T;
-    export function visitEachChild(node: Node, visitor: (node: Node) => VisitResult<Node>, context: LexicalEnvironment): Node {
+    export function visitEachChild<T extends Node>(node: T, visitor: (node: Node) => VisitResult<Node>, context: TransformationContext): T;
+    export function visitEachChild(node: Node, visitor: (node: Node) => VisitResult<Node>, context: TransformationContext): Node {
         if (node === undefined) {
             return undefined;
         }
@@ -697,6 +754,7 @@ namespace ts {
                 return updateParameter(<ParameterDeclaration>node,
                     visitNodes((<ParameterDeclaration>node).decorators, visitor, isDecorator),
                     visitNodes((<ParameterDeclaration>node).modifiers, visitor, isModifier),
+                    (<ParameterDeclaration>node).dotDotDotToken,
                     visitNode((<ParameterDeclaration>node).name, visitor, isBindingName),
                     visitNode((<ParameterDeclaration>node).type, visitor, isTypeNode, /*optional*/ true),
                     visitNode((<ParameterDeclaration>node).initializer, visitor, isExpression, /*optional*/ true));
@@ -716,41 +774,33 @@ namespace ts {
                     visitNodes((<MethodDeclaration>node).modifiers, visitor, isModifier),
                     visitNode((<MethodDeclaration>node).name, visitor, isPropertyName),
                     visitNodes((<MethodDeclaration>node).typeParameters, visitor, isTypeParameter),
-                    (context.startLexicalEnvironment(), visitNodes((<MethodDeclaration>node).parameters, visitor, isParameter)),
+                    visitParameterList((<MethodDeclaration>node).parameters, visitor, context),
                     visitNode((<MethodDeclaration>node).type, visitor, isTypeNode, /*optional*/ true),
-                    mergeFunctionBodyLexicalEnvironment(
-                        visitNode((<MethodDeclaration>node).body, visitor, isFunctionBody, /*optional*/ true),
-                        context.endLexicalEnvironment()));
+                    visitFunctionBody((<MethodDeclaration>node).body, visitor, context));
 
             case SyntaxKind.Constructor:
                 return updateConstructor(<ConstructorDeclaration>node,
                     visitNodes((<ConstructorDeclaration>node).decorators, visitor, isDecorator),
                     visitNodes((<ConstructorDeclaration>node).modifiers, visitor, isModifier),
-                    (context.startLexicalEnvironment(), visitNodes((<ConstructorDeclaration>node).parameters, visitor, isParameter)),
-                    mergeFunctionBodyLexicalEnvironment(
-                        visitNode((<ConstructorDeclaration>node).body, visitor, isFunctionBody, /*optional*/ true),
-                        context.endLexicalEnvironment()));
+                    visitParameterList((<ConstructorDeclaration>node).parameters, visitor, context),
+                    visitFunctionBody((<ConstructorDeclaration>node).body, visitor, context));
 
             case SyntaxKind.GetAccessor:
                 return updateGetAccessor(<GetAccessorDeclaration>node,
                     visitNodes((<GetAccessorDeclaration>node).decorators, visitor, isDecorator),
                     visitNodes((<GetAccessorDeclaration>node).modifiers, visitor, isModifier),
                     visitNode((<GetAccessorDeclaration>node).name, visitor, isPropertyName),
-                    (context.startLexicalEnvironment(), visitNodes((<GetAccessorDeclaration>node).parameters, visitor, isParameter)),
+                    visitParameterList((<GetAccessorDeclaration>node).parameters, visitor, context),
                     visitNode((<GetAccessorDeclaration>node).type, visitor, isTypeNode, /*optional*/ true),
-                    mergeFunctionBodyLexicalEnvironment(
-                        visitNode((<GetAccessorDeclaration>node).body, visitor, isFunctionBody, /*optional*/ true),
-                        context.endLexicalEnvironment()));
+                    visitFunctionBody((<GetAccessorDeclaration>node).body, visitor, context));
 
             case SyntaxKind.SetAccessor:
                 return updateSetAccessor(<SetAccessorDeclaration>node,
                     visitNodes((<SetAccessorDeclaration>node).decorators, visitor, isDecorator),
                     visitNodes((<SetAccessorDeclaration>node).modifiers, visitor, isModifier),
                     visitNode((<SetAccessorDeclaration>node).name, visitor, isPropertyName),
-                    (context.startLexicalEnvironment(), visitNodes((<SetAccessorDeclaration>node).parameters, visitor, isParameter)),
-                    mergeFunctionBodyLexicalEnvironment(
-                        visitNode((<SetAccessorDeclaration>node).body, visitor, isFunctionBody, /*optional*/ true),
-                        context.endLexicalEnvironment()));
+                    visitParameterList((<SetAccessorDeclaration>node).parameters, visitor, context),
+                    visitFunctionBody((<SetAccessorDeclaration>node).body, visitor, context));
 
             // Binding patterns
             case SyntaxKind.ObjectBindingPattern:
@@ -763,6 +813,7 @@ namespace ts {
 
             case SyntaxKind.BindingElement:
                 return updateBindingElement(<BindingElement>node,
+                    (<BindingElement>node).dotDotDotToken,
                     visitNode((<BindingElement>node).propertyName, visitor, isPropertyName, /*optional*/ true),
                     visitNode((<BindingElement>node).name, visitor, isBindingName),
                     visitNode((<BindingElement>node).initializer, visitor, isExpression, /*optional*/ true));
@@ -812,21 +863,17 @@ namespace ts {
                     visitNodes((<FunctionExpression>node).modifiers, visitor, isModifier),
                     visitNode((<FunctionExpression>node).name, visitor, isPropertyName),
                     visitNodes((<FunctionExpression>node).typeParameters, visitor, isTypeParameter),
-                    (context.startLexicalEnvironment(), visitNodes((<FunctionExpression>node).parameters, visitor, isParameter)),
+                    visitParameterList((<FunctionExpression>node).parameters, visitor, context),
                     visitNode((<FunctionExpression>node).type, visitor, isTypeNode, /*optional*/ true),
-                    mergeFunctionBodyLexicalEnvironment(
-                        visitNode((<FunctionExpression>node).body, visitor, isFunctionBody, /*optional*/ true),
-                        context.endLexicalEnvironment()));
+                    visitFunctionBody((<FunctionExpression>node).body, visitor, context));
 
             case SyntaxKind.ArrowFunction:
                 return updateArrowFunction(<ArrowFunction>node,
                     visitNodes((<ArrowFunction>node).modifiers, visitor, isModifier),
                     visitNodes((<ArrowFunction>node).typeParameters, visitor, isTypeParameter),
-                    (context.startLexicalEnvironment(), visitNodes((<ArrowFunction>node).parameters, visitor, isParameter)),
+                    visitParameterList((<ArrowFunction>node).parameters, visitor, context),
                     visitNode((<ArrowFunction>node).type, visitor, isTypeNode, /*optional*/ true),
-                    mergeFunctionBodyLexicalEnvironment(
-                        visitNode((<ArrowFunction>node).body, visitor, isConciseBody, /*optional*/ true),
-                        context.endLexicalEnvironment()));
+                    visitFunctionBody((<ArrowFunction>node).body, visitor, context));
 
             case SyntaxKind.DeleteExpression:
                 return updateDelete(<DeleteExpression>node,
@@ -872,9 +919,9 @@ namespace ts {
                 return updateYield(<YieldExpression>node,
                     visitNode((<YieldExpression>node).expression, visitor, isExpression));
 
-            case SyntaxKind.SpreadElementExpression:
-                return updateSpread(<SpreadElementExpression>node,
-                    visitNode((<SpreadElementExpression>node).expression, visitor, isExpression));
+            case SyntaxKind.SpreadElement:
+                return updateSpread(<SpreadElement>node,
+                    visitNode((<SpreadElement>node).expression, visitor, isExpression));
 
             case SyntaxKind.ClassExpression:
                 return updateClassExpression(<ClassExpression>node,
@@ -997,11 +1044,9 @@ namespace ts {
                     visitNodes((<FunctionDeclaration>node).modifiers, visitor, isModifier),
                     visitNode((<FunctionDeclaration>node).name, visitor, isPropertyName),
                     visitNodes((<FunctionDeclaration>node).typeParameters, visitor, isTypeParameter),
-                    (context.startLexicalEnvironment(), visitNodes((<FunctionDeclaration>node).parameters, visitor, isParameter)),
+                    visitParameterList((<FunctionDeclaration>node).parameters, visitor, context),
                     visitNode((<FunctionDeclaration>node).type, visitor, isTypeNode, /*optional*/ true),
-                    mergeFunctionBodyLexicalEnvironment(
-                        visitNode((<FunctionDeclaration>node).body, visitor, isFunctionBody, /*optional*/ true),
-                        context.endLexicalEnvironment()));
+                    visitFunctionBody((<FunctionExpression>node).body, visitor, context));
 
             case SyntaxKind.ClassDeclaration:
                 return updateClassDeclaration(<ClassDeclaration>node,
@@ -1127,15 +1172,14 @@ namespace ts {
                     visitNode((<ShorthandPropertyAssignment>node).name, visitor, isIdentifier),
                     visitNode((<ShorthandPropertyAssignment>node).objectAssignmentInitializer, visitor, isExpression));
 
-            // Top-level nodes
+            case SyntaxKind.SpreadAssignment:
+                return updateSpreadAssignment(node as SpreadAssignment,
+                    visitNode((node as SpreadAssignment).expression, visitor, isExpression));
+
+           // Top-level nodes
             case SyntaxKind.SourceFile:
-                context.startLexicalEnvironment();
                 return updateSourceFileNode(<SourceFile>node,
-                    createNodeArray(
-                        concatenate(
-                            visitNodes((<SourceFile>node).statements, visitor, isStatement),
-                            context.endLexicalEnvironment()),
-                        (<SourceFile>node).statements));
+                    visitLexicalEnvironment((<SourceFile>node).statements, visitor, context));
 
             // Transformation nodes
             case SyntaxKind.PartiallyEmittedExpression:
@@ -1169,6 +1213,24 @@ namespace ts {
         // return node;
     }
 
+    /**
+     * Merges generated lexical declarations into a new statement list.
+     */
+    export function mergeLexicalEnvironment(statements: NodeArray<Statement>, declarations: Statement[]): NodeArray<Statement>;
+    /**
+     * Appends generated lexical declarations to an array of statements.
+     */
+    export function mergeLexicalEnvironment(statements: Statement[], declarations: Statement[]): Statement[];
+    export function mergeLexicalEnvironment(statements: Statement[], declarations: Statement[]) {
+        if (!some(declarations)) {
+            return statements;
+        }
+        return isNodeArray(statements)
+            ? createNodeArray(concatenate(statements, declarations), statements)
+            : addRange(statements, declarations);
+    }
+
+
     /**
      * Merges generated lexical declarations into the FunctionBody of a non-arrow function-like declaration.
      *
@@ -1239,13 +1301,25 @@ namespace ts {
         if (node === undefined) {
             return TransformFlags.None;
         }
-        else if (node.transformFlags & TransformFlags.HasComputedFlags) {
+        if (node.transformFlags & TransformFlags.HasComputedFlags) {
             return node.transformFlags & ~getTransformFlagsSubtreeExclusions(node.kind);
         }
-        else {
-            const subtreeFlags = aggregateTransformFlagsForSubtree(node);
-            return computeTransformFlagsForNode(node, subtreeFlags);
+        const subtreeFlags = aggregateTransformFlagsForSubtree(node);
+        return computeTransformFlagsForNode(node, subtreeFlags);
+    }
+
+    function aggregateTransformFlagsForNodeArray(nodes: NodeArray<Node>): TransformFlags {
+        if (nodes === undefined) {
+            return TransformFlags.None;
         }
+        let subtreeFlags = TransformFlags.None;
+        let nodeArrayFlags = TransformFlags.None;
+        for (const node of nodes) {
+            subtreeFlags |= aggregateTransformFlagsForNode(node);
+            nodeArrayFlags |= node.transformFlags & ~TransformFlags.HasComputedFlags;
+        }
+        nodes.transformFlags = nodeArrayFlags | TransformFlags.HasComputedFlags;
+        return subtreeFlags;
     }
 
     /**
@@ -1254,20 +1328,24 @@ namespace ts {
     function aggregateTransformFlagsForSubtree(node: Node): TransformFlags {
         // We do not transform ambient declarations or types, so there is no need to
         // recursively aggregate transform flags.
-        if (hasModifier(node, ModifierFlags.Ambient) || isTypeNode(node)) {
+        if (hasModifier(node, ModifierFlags.Ambient) || (isTypeNode(node) && node.kind !== SyntaxKind.ExpressionWithTypeArguments)) {
             return TransformFlags.None;
         }
 
         // Aggregate the transform flags of each child.
-        return reduceEachChild(node, aggregateTransformFlagsForChildNode, TransformFlags.None);
+        return reduceEachChild(node, TransformFlags.None, aggregateTransformFlagsForChildNode, aggregateTransformFlagsForChildNodes);
     }
 
     /**
      * Aggregates the TransformFlags of a child node with the TransformFlags of its
      * siblings.
      */
-    function aggregateTransformFlagsForChildNode(transformFlags: TransformFlags, child: Node): TransformFlags {
-        return transformFlags | aggregateTransformFlagsForNode(child);
+    function aggregateTransformFlagsForChildNode(transformFlags: TransformFlags, node: Node): TransformFlags {
+        return transformFlags | aggregateTransformFlagsForNode(node);
+    }
+
+    function aggregateTransformFlagsForChildNodes(transformFlags: TransformFlags, nodes: NodeArray<Node>): TransformFlags {
+        return transformFlags | aggregateTransformFlagsForNodeArray(nodes);
     }
 
     export namespace Debug {
@@ -1279,6 +1357,13 @@ namespace ts {
             ? (node: Node, message?: string) => assert(false, message || "Unexpected node.", () => `Node ${formatSyntaxKind(node.kind)} was unexpected.`)
             : noop;
 
+        export const assertEachNode = shouldAssert(AssertionLevel.Normal)
+            ? (nodes: Node[], test: (node: Node) => boolean, message?: string) => assert(
+                    test === undefined || every(nodes, test),
+                    message || "Unexpected node.",
+                    () => `Node array did not pass test '${getFunctionName(test)}'.`)
+            : noop;
+
         export const assertNode = shouldAssert(AssertionLevel.Normal)
             ? (node: Node, test: (node: Node) => boolean, message?: string) => assert(
                     test === undefined || test(node),
@@ -1286,6 +1371,27 @@ namespace ts {
                     () => `Node ${formatSyntaxKind(node.kind)} did not pass test '${getFunctionName(test)}'.`)
             : noop;
 
+        export const assertOptionalNode = shouldAssert(AssertionLevel.Normal)
+            ? (node: Node, test: (node: Node) => boolean, message?: string) => assert(
+                    test === undefined || node === undefined || test(node),
+                    message || "Unexpected node.",
+                    () => `Node ${formatSyntaxKind(node.kind)} did not pass test '${getFunctionName(test)}'.`)
+            : noop;
+
+        export const assertOptionalToken = shouldAssert(AssertionLevel.Normal)
+            ? (node: Node, kind: SyntaxKind, message?: string) => assert(
+                    kind === undefined || node === undefined || node.kind === kind,
+                    message || "Unexpected node.",
+                    () => `Node ${formatSyntaxKind(node.kind)} was not a '${formatSyntaxKind(kind)}' token.`)
+            : noop;
+
+        export const assertMissingNode = shouldAssert(AssertionLevel.Normal)
+            ? (node: Node, message?: string) => assert(
+                    node === undefined,
+                    message || "Unexpected node.",
+                    () => `Node ${formatSyntaxKind(node.kind)} was unexpected'.`)
+            : noop;
+
         function getFunctionName(func: Function) {
             if (typeof func !== "function") {
                 return "";

src/harness/compilerRunner.ts

@@ -170,7 +170,7 @@ class CompilerBaselineRunner extends RunnerBase {
             });
 
             it("Correct Sourcemap output for " + fileName, () => {
-                Harness.Compiler.doSourcemapBaseline(justName, options, result);
+                Harness.Compiler.doSourcemapBaseline(justName, options, result, harnessSettings);
             });
 
             it("Correct type/symbol baselines for " + fileName, () => {

src/harness/fourslash.ts

@@ -341,6 +341,7 @@ namespace FourSlash {
                 insertSpaceAfterCommaDelimiter: true,
                 insertSpaceAfterSemicolonInForStatements: true,
                 insertSpaceBeforeAndAfterBinaryOperators: true,
+                insertSpaceAfterConstructor: false,
                 insertSpaceAfterKeywordsInControlFlowStatements: true,
                 insertSpaceAfterFunctionKeywordForAnonymousFunctions: false,
                 insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis: false,
@@ -478,7 +479,7 @@ namespace FourSlash {
                 endPos = endMarker.position;
             }
 
-            errors.forEach(function(error: ts.Diagnostic) {
+            errors.forEach(function (error: ts.Diagnostic) {
                 if (predicate(error.start, error.start + error.length, startPos, endPos)) {
                     exists = true;
                 }
@@ -495,7 +496,7 @@ namespace FourSlash {
                 Harness.IO.log("Unexpected error(s) found.  Error list is:");
             }
 
-            errors.forEach(function(error: ts.Diagnostic) {
+            errors.forEach(function (error: ts.Diagnostic) {
                 Harness.IO.log("  minChar: " + error.start +
                     ", limChar: " + (error.start + error.length) +
                     ", message: " + ts.flattenDiagnosticMessageText(error.messageText, Harness.IO.newLine()) + "\n");
@@ -607,23 +608,13 @@ namespace FourSlash {
             });
         }
 
-        public verifyMemberListContains(symbol: string, text?: string, documentation?: string, kind?: string) {
-            const members = this.getMemberListAtCaret();
-            if (members) {
-                this.assertItemInCompletionList(members.entries, symbol, text, documentation, kind);
-            }
-            else {
-                this.raiseError("Expected a member list, but none was provided");
-            }
-        }
-
-        public verifyMemberListCount(expectedCount: number, negative: boolean) {
+        public verifyCompletionListCount(expectedCount: number, negative: boolean) {
             if (expectedCount === 0 && negative) {
-                this.verifyMemberListIsEmpty(/*negative*/ false);
+                this.verifyCompletionListIsEmpty(/*negative*/ false);
                 return;
             }
 
-            const members = this.getMemberListAtCaret();
+            const members = this.getCompletionListAtCaret();
 
             if (members) {
                 const match = members.entries.length === expectedCount;
@@ -637,13 +628,6 @@ namespace FourSlash {
             }
         }
 
-        public verifyMemberListDoesNotContain(symbol: string) {
-            const members = this.getMemberListAtCaret();
-            if (members && members.entries.filter(e => e.name === symbol).length !== 0) {
-                this.raiseError(`Member list did contain ${symbol}`);
-            }
-        }
-
         public verifyCompletionListItemsCountIsGreaterThan(count: number, negative: boolean) {
             const completions = this.getCompletionListAtCaret();
             const itemsCount = completions.entries.length;
@@ -685,16 +669,6 @@ namespace FourSlash {
             }
         }
 
-        public verifyMemberListIsEmpty(negative: boolean) {
-            const members = this.getMemberListAtCaret();
-            if ((!members || members.entries.length === 0) && negative) {
-                this.raiseError("Member list is empty at Caret");
-            }
-            else if ((members && members.entries.length !== 0) && !negative) {
-                this.raiseError(`Member list is not empty at Caret:\nMember List contains: ${stringify(members.entries.map(e => e.name))}`);
-            }
-        }
-
         public verifyCompletionListIsEmpty(negative: boolean) {
             const completions = this.getCompletionListAtCaret();
             if ((!completions || completions.entries.length === 0) && negative) {
@@ -892,10 +866,6 @@ namespace FourSlash {
             this.raiseError(`verifyReferencesAtPositionListContains failed - could not find the item: ${stringify(missingItem)} in the returned list: (${stringify(references)})`);
         }
 
-        private getMemberListAtCaret() {
-            return this.languageService.getCompletionsAtPosition(this.activeFile.fileName, this.currentCaretPosition);
-        }
-
         private getCompletionListAtCaret() {
             return this.languageService.getCompletionsAtPosition(this.activeFile.fileName, this.currentCaretPosition);
         }
@@ -1353,11 +1323,6 @@ namespace FourSlash {
             Harness.IO.log(stringify(sigHelp));
         }
 
-        public printMemberListMembers() {
-            const members = this.getMemberListAtCaret();
-            this.printMembersOrCompletions(members);
-        }
-
         public printCompletionListMembers() {
             const completions = this.getCompletionListAtCaret();
             this.printMembersOrCompletions(completions);
@@ -2013,13 +1978,13 @@ namespace FourSlash {
                 this.raiseError("Errors expected.");
             }
 
-            if (diagnostics.length > 1 && errorCode !== undefined) {
+            if (diagnostics.length > 1 && errorCode === undefined) {
                 this.raiseError("When there's more than one error, you must specify the errror to fix.");
             }
 
             const diagnostic = !errorCode ? diagnostics[0] : ts.find(diagnostics, d => d.code == errorCode);
 
-            return this.languageService.getCodeFixesAtPosition(fileName, diagnostic.start, diagnostic.length, [diagnostic.code]);
+            return this.languageService.getCodeFixesAtPosition(fileName, diagnostic.start, diagnostic.start + diagnostic.length, [diagnostic.code]);
         }
 
         public verifyCodeFixAtPosition(expectedText: string, errorCode?: number) {
@@ -2046,6 +2011,34 @@ namespace FourSlash {
             }
         }
 
+        public verifyImportFixAtPosition(expectedTextArray: string[], errorCode?: number) {
+            const ranges = this.getRanges();
+            if (ranges.length == 0) {
+                this.raiseError("At least one range should be specified in the testfile.");
+            }
+
+            const codeFixes = this.getCodeFixes(errorCode);
+
+            if (!codeFixes || codeFixes.length == 0) {
+                this.raiseError("No codefixes returned.");
+            }
+
+            const actualTextArray: string[] = [];
+            const scriptInfo = this.languageServiceAdapterHost.getScriptInfo(codeFixes[0].changes[0].fileName);
+            const originalContent = scriptInfo.content;
+            for (const codeFix of codeFixes) {
+                this.applyEdits(codeFix.changes[0].fileName, codeFix.changes[0].textChanges, /*isFormattingEdit*/ false);
+                actualTextArray.push(this.normalizeNewlines(this.rangeText(ranges[0])));
+                scriptInfo.updateContent(originalContent);
+            }
+            const sortedExpectedArray = ts.map(expectedTextArray, str => this.normalizeNewlines(str)).sort();
+            const sortedActualArray = actualTextArray.sort();
+            if (!ts.arrayIsEqualTo(sortedExpectedArray, sortedActualArray)) {
+                this.raiseError(
+                    `Actual text array doesn't match expected text array. \nActual: \n"${sortedActualArray.join("\n\n")}"\n---\nExpected: \n'${sortedExpectedArray.join("\n\n")}'`);
+            }
+        }
+
         public verifyDocCommentTemplate(expected?: ts.TextInsertion) {
             const name = "verifyDocCommentTemplate";
             const actual = this.languageService.getDocCommentTemplateAtPosition(this.activeFile.fileName, this.currentCaretPosition);
@@ -2079,6 +2072,10 @@ namespace FourSlash {
             });
         }
 
+        private normalizeNewlines(str: string) {
+            return str.replace(/\r?\n/g, "\n");
+        }
+
         public verifyBraceCompletionAtPosition(negative: boolean, openingBrace: string) {
 
             const openBraceMap = ts.createMap<ts.CharacterCodes>({
@@ -2606,7 +2603,7 @@ ${code}
                                 resetLocalData();
                             }
 
-                            currentFileName = basePath + "/" + value;
+                            currentFileName = ts.isRootedDiskPath(value) ? value : basePath + "/" + value;
                             currentFileOptions[key] = value;
                         }
                         else {
@@ -3029,19 +3026,8 @@ namespace FourSlashInterface {
             }
         }
 
-        // Verifies the member list contains the specified symbol. The
-        // member list is brought up if necessary
-        public memberListContains(symbol: string, text?: string, documentation?: string, kind?: string) {
-            if (this.negative) {
-                this.state.verifyMemberListDoesNotContain(symbol);
-            }
-            else {
-                this.state.verifyMemberListContains(symbol, text, documentation, kind);
-            }
-        }
-
-        public memberListCount(expectedCount: number) {
-            this.state.verifyMemberListCount(expectedCount, this.negative);
+        public completionListCount(expectedCount: number) {
+            this.state.verifyCompletionListCount(expectedCount, this.negative);
         }
 
         // Verifies the completion list contains the specified symbol. The
@@ -3077,10 +3063,6 @@ namespace FourSlashInterface {
             this.state.verifyCompletionListAllowsNewIdentifier(this.negative);
         }
 
-        public memberListIsEmpty() {
-            this.state.verifyMemberListIsEmpty(this.negative);
-        }
-
         public signatureHelpPresent() {
             this.state.verifySignatureHelpPresent(!this.negative);
         }
@@ -3303,6 +3285,10 @@ namespace FourSlashInterface {
             this.state.verifyCodeFixAtPosition(expectedText, errorCode);
         }
 
+        public importFixAtPosition(expectedTextArray: string[], errorCode?: number): void {
+            this.state.verifyImportFixAtPosition(expectedTextArray, errorCode);
+        }
+
         public navigationBar(json: any) {
             this.state.verifyNavigationBar(json);
         }
@@ -3478,10 +3464,6 @@ namespace FourSlashInterface {
             this.state.printCurrentSignatureHelp();
         }
 
-        public printMemberListMembers() {
-            this.state.printMemberListMembers();
-        }
-
         public printCompletionListMembers() {
             this.state.printCompletionListMembers();
         }
@@ -3542,11 +3524,8 @@ namespace FourSlashInterface {
             this.state.formatOnType(this.state.getMarkerByName(posMarker).position, key);
         }
 
-        public setOption(name: string, value: number): void;
-        public setOption(name: string, value: string): void;
-        public setOption(name: string, value: boolean): void;
-        public setOption(name: string, value: any): void {
-            (<any>this.state.formatCodeSettings)[name] = value;
+        public setOption(name: keyof ts.FormatCodeSettings, value: number | string | boolean): void {
+            this.state.formatCodeSettings[name] = value;
         }
     }
 

src/harness/harness.ts

@@ -85,7 +85,7 @@ namespace Utils {
                 eval(fileContents);
                 break;
             case ExecutionEnvironment.Node:
-                let vm = require("vm");
+                const vm = require("vm");
                 if (nodeContext) {
                     vm.runInNewContext(fileContents, nodeContext, fileName);
                 }
@@ -175,9 +175,9 @@ namespace Utils {
                     assert.isFalse(array.end > node.end, "array.end > node.end");
                     assert.isFalse(array.pos < currentPos, "array.pos < currentPos");
 
-                    for (let i = 0, n = array.length; i < n; i++) {
-                        assert.isFalse(array[i].pos < currentPos, "array[i].pos < currentPos");
-                        currentPos = array[i].end;
+                    for (const item of array) {
+                        assert.isFalse(item.pos < currentPos, "array[i].pos < currentPos");
+                        currentPos = item.end;
                     }
 
                     currentPos = array.end;
@@ -344,7 +344,7 @@ namespace Utils {
 
         assert.equal(array1.length, array2.length, "array1.length !== array2.length");
 
-        for (let i = 0, n = array1.length; i < n; i++) {
+        for (let i = 0; i < array1.length; i++) {
             const d1 = array1[i];
             const d2 = array2[i];
 
@@ -400,7 +400,7 @@ namespace Utils {
         assert.equal(array1.end, array2.end, "array1.end !== array2.end");
         assert.equal(array1.length, array2.length, "array1.length !== array2.length");
 
-        for (let i = 0, n = array1.length; i < n; i++) {
+        for (let i = 0; i < array1.length; i++) {
             assertStructuralEquals(array1[i], array2[i]);
         }
     }
@@ -470,19 +470,6 @@ namespace Utils {
     }
 }
 
-namespace Harness.Path {
-    export function getFileName(fullPath: string) {
-        return fullPath.replace(/^.*[\\\/]/, "");
-    }
-
-    export function filePath(fullPath: string) {
-        fullPath = ts.normalizeSlashes(fullPath);
-        const components = fullPath.split("/");
-        const path: string[] = components.slice(0, components.length - 1);
-        return path.join("/") + "/";
-    }
-}
-
 namespace Harness {
     export interface IO {
         newLine(): string;
@@ -971,28 +958,38 @@ namespace Harness {
             // Local get canonical file name function, that depends on passed in parameter for useCaseSensitiveFileNames
             const getCanonicalFileName = ts.createGetCanonicalFileName(useCaseSensitiveFileNames);
 
-            const realPathMap: ts.FileMap<string> = ts.createFileMap<string>();
-            const fileMap: ts.FileMap<() => ts.SourceFile> = ts.createFileMap<() => ts.SourceFile>();
+            /** Maps a symlink name to a realpath. Used only for exposing `realpath`. */
+            const realPathMap = ts.createFileMap<string>();
+            /**
+             * Maps a file name to a source file.
+             * This will have a different SourceFile for every symlink pointing to that file;
+             * if the program resolves realpaths then symlink entries will be ignored.
+             */
+            const fileMap = ts.createFileMap<ts.SourceFile>();
             for (const file of inputFiles) {
                 if (file.content !== undefined) {
                     const fileName = ts.normalizePath(file.unitName);
                     const path = ts.toPath(file.unitName, currentDirectory, getCanonicalFileName);
                     if (file.fileOptions && file.fileOptions["symlink"]) {
-                        const link = file.fileOptions["symlink"];
-                        const linkPath = ts.toPath(link, currentDirectory, getCanonicalFileName);
-                        realPathMap.set(linkPath, fileName);
-                        fileMap.set(path, (): ts.SourceFile => { throw new Error("Symlinks should always be resolved to a realpath first"); });
+                        const links = file.fileOptions["symlink"].split(",");
+                        for (const link of links) {
+                            const linkPath = ts.toPath(link, currentDirectory, getCanonicalFileName);
+                            realPathMap.set(linkPath, fileName);
+                            // Create a different SourceFile for every symlink.
+                            const sourceFile = createSourceFileAndAssertInvariants(linkPath, file.content, scriptTarget);
+                            fileMap.set(linkPath, sourceFile);
+                        }
                     }
                     const sourceFile = createSourceFileAndAssertInvariants(fileName, file.content, scriptTarget);
-                    fileMap.set(path, () => sourceFile);
+                    fileMap.set(path, sourceFile);
                 }
             }
 
             function getSourceFile(fileName: string) {
                 fileName = ts.normalizePath(fileName);
-                const path = ts.toPath(fileName, currentDirectory, getCanonicalFileName);
-                if (fileMap.contains(path)) {
-                    return fileMap.get(path)();
+                const fromFileMap = fileMap.get(toPath(fileName));
+                if (fromFileMap) {
+                    return fromFileMap;
                 }
                 else if (fileName === fourslashFileName) {
                     const tsFn = "tests/cases/fourslash/" + fourslashFileName;
@@ -1011,6 +1008,9 @@ namespace Harness {
                     newLineKind === ts.NewLineKind.LineFeed ? lineFeed :
                         Harness.IO.newLine();
 
+            function toPath(fileName: string): ts.Path {
+                return ts.toPath(fileName, currentDirectory, getCanonicalFileName);
+            }
 
             return {
                 getCurrentDirectory: () => currentDirectory,
@@ -1020,24 +1020,26 @@ namespace Harness {
                 getCanonicalFileName,
                 useCaseSensitiveFileNames: () => useCaseSensitiveFileNames,
                 getNewLine: () => newLine,
-                fileExists: fileName => {
-                    const path = ts.toPath(fileName, currentDirectory, getCanonicalFileName);
-                    return fileMap.contains(path) || (realPathMap && realPathMap.contains(path));
-                },
+                fileExists: fileName => fileMap.contains(toPath(fileName)),
                 readFile: (fileName: string): string => {
-                    return fileMap.get(ts.toPath(fileName, currentDirectory, getCanonicalFileName))().getText();
+                    const file = fileMap.get(toPath(fileName));
+                    if (ts.endsWith(fileName, "json")) {
+                        // strip comments
+                        return file.getText();
+                    }
+                    return file.text;
+                },
+                realpath: (fileName: string): ts.Path => {
+                    const path = toPath(fileName);
+                    return (realPathMap.get(path) as ts.Path) || path;
                 },
-                realpath: realPathMap && ((f: string) => {
-                    const path = ts.toPath(f, currentDirectory, getCanonicalFileName);
-                    return realPathMap.get(path) || path;
-                }),
                 directoryExists: dir => {
                     let path = ts.toPath(dir, currentDirectory, getCanonicalFileName);
                     // Strip trailing /, which may exist if the path is a drive root
                     if (path[path.length - 1] === "/") {
                         path = <ts.Path>path.substr(0, path.length - 1);
                     }
-                    return mapHasFileInDirectory(path, fileMap) || mapHasFileInDirectory(path, realPathMap);
+                    return mapHasFileInDirectory(path, fileMap);
                 },
                 getDirectories: d => {
                     const path = ts.toPath(d, currentDirectory, getCanonicalFileName);
@@ -1090,7 +1092,9 @@ namespace Harness {
             { name: "suppressOutputPathCheck", type: "boolean" },
             { name: "noImplicitReferences", type: "boolean" },
             { name: "currentDirectory", type: "string" },
-            { name: "symlink", type: "string" }
+            { name: "symlink", type: "string" },
+            // Emitted js baseline will print full paths for every output file
+            { name: "fullEmitPaths", type: "boolean" }
         ];
 
         let optionsIndex: ts.Map<ts.CommandLineOption>;
@@ -1483,7 +1487,7 @@ namespace Harness {
             }
 
             if (typesError && symbolsError) {
-                throw new Error(typesError.message + ts.sys.newLine + symbolsError.message);
+                throw new Error(typesError.message + Harness.IO.newLine() + symbolsError.message);
             }
 
             if (typesError) {
@@ -1565,7 +1569,7 @@ namespace Harness {
             return file.writeByteOrderMark ? "\u00EF\u00BB\u00BF" : "";
         }
 
-        export function doSourcemapBaseline(baselinePath: string, options: ts.CompilerOptions, result: CompilerResult) {
+        export function doSourcemapBaseline(baselinePath: string, options: ts.CompilerOptions, result: CompilerResult, harnessSettings: Harness.TestCaseParser.CompilerSettings) {
             if (options.inlineSourceMap) {
                 if (result.sourceMaps.length > 0) {
                     throw new Error("No sourcemap files should be generated if inlineSourceMaps was set.");
@@ -1587,10 +1591,8 @@ namespace Harness {
                     }
 
                     let sourceMapCode = "";
-                    for (let i = 0; i < result.sourceMaps.length; i++) {
-                        sourceMapCode += "//// [" + Harness.Path.getFileName(result.sourceMaps[i].fileName) + "]\r\n";
-                        sourceMapCode += getByteOrderMarkText(result.sourceMaps[i]);
-                        sourceMapCode += result.sourceMaps[i].code;
+                    for (const sourceMap of result.sourceMaps) {
+                        sourceMapCode += fileOutput(sourceMap, harnessSettings);
                     }
 
                     return sourceMapCode;
@@ -1611,23 +1613,19 @@ namespace Harness {
                     tsCode += "//// [" + header + "] ////\r\n\r\n";
                 }
                 for (let i = 0; i < tsSources.length; i++) {
-                    tsCode += "//// [" + Harness.Path.getFileName(tsSources[i].unitName) + "]\r\n";
+                    tsCode += "//// [" + ts.getBaseFileName(tsSources[i].unitName) + "]\r\n";
                     tsCode += tsSources[i].content + (i < (tsSources.length - 1) ? "\r\n" : "");
                 }
 
                 let jsCode = "";
-                for (let i = 0; i < result.files.length; i++) {
-                    jsCode += "//// [" + Harness.Path.getFileName(result.files[i].fileName) + "]\r\n";
-                    jsCode += getByteOrderMarkText(result.files[i]);
-                    jsCode += result.files[i].code;
+                for (const file of result.files) {
+                    jsCode += fileOutput(file, harnessSettings);
                 }
 
                 if (result.declFilesCode.length > 0) {
                     jsCode += "\r\n\r\n";
-                    for (let i = 0; i < result.declFilesCode.length; i++) {
-                        jsCode += "//// [" + Harness.Path.getFileName(result.declFilesCode[i].fileName) + "]\r\n";
-                        jsCode += getByteOrderMarkText(result.declFilesCode[i]);
-                        jsCode += result.declFilesCode[i].code;
+                    for (const declFile of result.declFilesCode) {
+                        jsCode += fileOutput(declFile, harnessSettings);
                     }
                 }
 
@@ -1652,6 +1650,11 @@ namespace Harness {
             });
         }
 
+        function fileOutput(file: GeneratedFile, harnessSettings: Harness.TestCaseParser.CompilerSettings): string {
+            const fileName = harnessSettings["fullEmitPaths"] ? file.fileName : ts.getBaseFileName(file.fileName);
+            return "//// [" + fileName + "]\r\n" + getByteOrderMarkText(file) + file.code;
+        }
+
         export function collateOutputs(outputFiles: Harness.Compiler.GeneratedFile[]): string {
             // Collect, test, and sort the fileNames
             outputFiles.sort((a, b) => ts.compareStrings(cleanName(a.fileName), cleanName(b.fileName)));
@@ -1768,7 +1771,7 @@ namespace Harness {
         }
 
         // Regex for parsing options in the format "@Alpha: Value of any sort"
-        const optionRegex = /^[\/]{2}\s*@(\w+)\s*:\s*(\S*)/gm;  // multiple matches on multiple lines
+        const optionRegex = /^[\/]{2}\s*@(\w+)\s*:\s*([^\r\n]*)/gm;  // multiple matches on multiple lines
 
         function extractCompilerSettings(content: string): CompilerSettings {
             const opts: CompilerSettings = {};
@@ -1777,7 +1780,7 @@ namespace Harness {
             /* tslint:disable:no-null-keyword */
             while ((match = optionRegex.exec(content)) !== null) {
             /* tslint:enable:no-null-keyword */
-                opts[match[1]] = match[2];
+                opts[match[1]] = match[2].trim();
             }
 
             return opts;
@@ -1805,7 +1808,7 @@ namespace Harness {
                     // Comment line, check for global/file @options and record them
                     optionRegex.lastIndex = 0;
                     const metaDataName = testMetaData[1].toLowerCase();
-                    currentFileOptions[testMetaData[1]] = testMetaData[2];
+                    currentFileOptions[testMetaData[1]] = testMetaData[2].trim();
                     if (metaDataName !== "filename") {
                         continue;
                     }
@@ -1825,12 +1828,12 @@ namespace Harness {
                         // Reset local data
                         currentFileContent = undefined;
                         currentFileOptions = {};
-                        currentFileName = testMetaData[2];
+                        currentFileName = testMetaData[2].trim();
                         refs = [];
                     }
                     else {
                         // First metadata marker in the file
-                        currentFileName = testMetaData[2];
+                        currentFileName = testMetaData[2].trim();
                     }
                 }
                 else {
@@ -1848,7 +1851,7 @@ namespace Harness {
             }
 
             // normalize the fileName for the single file case
-            currentFileName = testUnitData.length > 0 || currentFileName ? currentFileName : Path.getFileName(fileName);
+            currentFileName = testUnitData.length > 0 || currentFileName ? currentFileName : ts.getBaseFileName(fileName);
 
             // EOF, push whatever remains
             const newTestFile2 = {
@@ -2012,7 +2015,7 @@ namespace Harness {
 
     export function isDefaultLibraryFile(filePath: string): boolean {
         // We need to make sure that the filePath is prefixed with "lib." not just containing "lib." and end with ".d.ts"
-        const fileName = Path.getFileName(filePath);
+        const fileName = ts.getBaseFileName(ts.normalizeSlashes(filePath));
         return ts.startsWith(fileName, "lib.") && ts.endsWith(fileName, ".d.ts");
     }
 

src/harness/runner.ts

@@ -61,6 +61,10 @@ function createRunner(kind: TestRunnerKind): RunnerBase {
     }
 }
 
+if (Harness.IO.tryEnableSourceMapsForHost && /^development$/i.test(Harness.IO.getEnvironmentVariable("NODE_ENV"))) {
+    Harness.IO.tryEnableSourceMapsForHost();
+}
+
 // users can define tests to run in mytest.config that will override cmd line args, otherwise use cmd line args (test.config), otherwise no options
 
 const mytestconfigFileName = "mytest.config";

src/harness/runnerbase.ts

@@ -32,7 +32,7 @@ abstract class RunnerBase {
     /** Replaces instances of full paths with fileNames only */
     static removeFullPaths(path: string) {
         // If its a full path (starts with "C:" or "/") replace with just the filename
-        let fixedPath = /^(\w:|\/)/.test(path) ? Harness.Path.getFileName(path) : path;
+        let fixedPath = /^(\w:|\/)/.test(path) ? ts.getBaseFileName(path) : path;
 
         // when running in the browser the 'full path' is the host name, shows up in error baselines
         const localHost = /http:\/localhost:\d+/g;

src/harness/rwcRunner.ts

@@ -199,7 +199,7 @@ namespace RWC {
                     }
                     // Do not include the library in the baselines to avoid noise
                     const baselineFiles = inputFiles.concat(otherFiles).filter(f => !Harness.isDefaultLibraryFile(f.unitName));
-                    const errors = compilerResult.errors.filter(e => !Harness.isDefaultLibraryFile(e.file.fileName));
+                    const errors = compilerResult.errors.filter(e => e.file && !Harness.isDefaultLibraryFile(e.file.fileName));
                     return Harness.Compiler.getErrorBaseline(baselineFiles, errors);
                 }, baselineOpts);
             });

src/harness/tsconfig.json

@@ -29,6 +29,7 @@
         "../compiler/visitor.ts",
         "../compiler/transformers/ts.ts",
         "../compiler/transformers/jsx.ts",
+        "../compiler/transformers/esnext.ts",
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
         "../compiler/transformers/es2015.ts",
@@ -107,7 +108,7 @@
         "./unittests/commandLineParsing.ts",
         "./unittests/configurationExtension.ts",
         "./unittests/convertCompilerOptionsFromJson.ts",
-        "./unittests/convertTypingOptionsFromJson.ts",
+        "./unittests/convertTypeAcquisitionFromJson.ts",
         "./unittests/tsserverProjectSystem.ts",
         "./unittests/matchFiles.ts",
         "./unittests/initializeTSConfig.ts",

src/harness/unittests/commandLineParsing.ts

@@ -60,7 +60,7 @@ namespace ts {
             assertParseResult(["--lib", "es5,invalidOption", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
@@ -165,7 +165,7 @@ namespace ts {
                         start: undefined,
                         length: undefined,
                     }, {
-                            messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017'",
+                            messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017', 'esnext'",
                             category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                             code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
@@ -263,7 +263,7 @@ namespace ts {
             assertParseResult(["--lib", "es5,", "es7", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
@@ -283,7 +283,7 @@ namespace ts {
             assertParseResult(["--lib", "es5, ", "es7", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 

src/harness/unittests/compileOnSave.ts

@@ -467,6 +467,36 @@ namespace ts.projectSystem {
     });
 
     describe("EmitFile test", () => {
+        it("should respect line endings", () => {
+            test("\n");
+            test("\r\n");
+
+            function test(newLine: string) {
+                const lines = ["var x = 1;", "var y = 2;"];
+                const path = "/a/app";
+                const f = {
+                    path: path + ".ts",
+                    content: lines.join(newLine)
+                };
+                const host = createServerHost([f], { newLine });
+                const session = createSession(host);
+                session.executeCommand(<server.protocol.OpenRequest>{
+                    seq: 1,
+                    type: "request",
+                    command: "open",
+                    arguments: { file: f.path }
+                });
+                session.executeCommand(<server.protocol.CompileOnSaveEmitFileRequest>{
+                    seq: 2,
+                    type: "request",
+                    command: "compileOnSaveEmitFile",
+                    arguments: { file: f.path }
+                });
+                const emitOutput = host.readFile(path + ".js");
+                assert.equal(emitOutput, f.content + newLine, "content of emit output should be identical with the input + newline");
+            }
+        })
+
         it("should emit specified file", () => {
             const file1 = {
                 path: "/a/b/f1.ts",
@@ -480,7 +510,7 @@ namespace ts.projectSystem {
                 path: "/a/b/tsconfig.json",
                 content: `{}`
             };
-            const host = createServerHost([file1, file2, configFile, libFile]);
+            const host = createServerHost([file1, file2, configFile, libFile], { newLine: "\r\n" });
             const typingsInstaller = createTestTypingsInstaller(host);
             const session = new server.Session(host, nullCancellationToken, /*useSingleInferredProject*/ false, typingsInstaller, Utils.byteLength, process.hrtime, nullLogger, /*canUseEvents*/ false);
 
@@ -492,5 +522,45 @@ namespace ts.projectSystem {
             assert.isTrue(host.fileExists(expectedEmittedFileName));
             assert.equal(host.readFile(expectedEmittedFileName), `"use strict";\r\nfunction Foo() { return 10; }\r\nexports.Foo = Foo;\r\n`);
         });
+
+        it("shoud not emit js files in external projects", () => {
+            const file1 = {
+                path: "/a/b/file1.ts",
+                content: "consonle.log('file1');"
+            };
+            // file2 has errors. The emitting should not be blocked.
+            const file2 = {
+                path: "/a/b/file2.js",
+                content: "console.log'file2');"
+            };
+            const file3 = {
+                path: "/a/b/file3.js",
+                content: "console.log('file3');"
+            };
+            const externalProjectName = "externalproject";
+            const host = createServerHost([file1, file2, file3, libFile]);
+            const session = createSession(host);
+            const projectService = session.getProjectService();
+
+            projectService.openExternalProject({
+                rootFiles: toExternalFiles([file1.path, file2.path]),
+                options: {
+                    allowJs: true,
+                    outFile: "dist.js",
+                    compileOnSave: true
+                },
+                projectFileName: externalProjectName
+            });
+
+            const emitRequest = makeSessionRequest<server.protocol.CompileOnSaveEmitFileRequestArgs>(CommandNames.CompileOnSaveEmitFile, { file: file1.path });
+            session.executeCommand(emitRequest);
+
+            const expectedOutFileName = "/a/b/dist.js";
+            assert.isTrue(host.fileExists(expectedOutFileName));
+            const outFileContent = host.readFile(expectedOutFileName);
+            assert.isTrue(outFileContent.indexOf(file1.content) !== -1);
+            assert.isTrue(outFileContent.indexOf(file2.content) === -1);
+            assert.isTrue(outFileContent.indexOf(file3.content) === -1);
+        });
     });
 }

src/harness/unittests/configurationExtension.ts

@@ -179,7 +179,7 @@ namespace ts {
                 testFailure("can error when 'extends' is neither relative nor rooted.", "extends2.json", [{
                     code: 18001,
                     category: DiagnosticCategory.Error,
-                    messageText: `The path in an 'extends' options must be relative or rooted.`
+                    messageText: `A path in an 'extends' option must be relative or rooted, but 'configs/base' is not.`
                 }]);
             });
         });

src/harness/unittests/convertCompilerOptionsFromJson.ts

@@ -176,7 +176,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017'",
+                        messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017', 'esnext'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -233,7 +233,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -264,7 +264,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -295,7 +295,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -326,7 +326,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]

src/harness/unittests/convertTypeAcquisitionFromJson.ts

@@ -2,12 +2,13 @@
 /// <reference path="..\..\compiler\commandLineParser.ts" />
 
 namespace ts {
-    describe("convertTypingOptionsFromJson", () => {
-        function assertTypingOptions(json: any, configFileName: string, expectedResult: { typingOptions: TypingOptions, errors: Diagnostic[] }) {
-            const { options: actualTypingOptions, errors: actualErrors } = convertTypingOptionsFromJson(json["typingOptions"], "/apath/", configFileName);
-            const parsedTypingOptions = JSON.stringify(actualTypingOptions);
-            const expectedTypingOptions = JSON.stringify(expectedResult.typingOptions);
-            assert.equal(parsedTypingOptions, expectedTypingOptions);
+    describe("convertTypeAcquisitionFromJson", () => {
+        function assertTypeAcquisition(json: any, configFileName: string, expectedResult: { typeAcquisition: TypeAcquisition, errors: Diagnostic[] }) {
+            const jsonOptions = json["typeAcquisition"] || json["typingOptions"];
+            const { options: actualTypeAcquisition, errors: actualErrors } = convertTypeAcquisitionFromJson(jsonOptions, "/apath/", configFileName);
+            const parsedTypeAcquisition = JSON.stringify(actualTypeAcquisition);
+            const expectedTypeAcquisition = JSON.stringify(expectedResult.typeAcquisition);
+            assert.equal(parsedTypeAcquisition, expectedTypeAcquisition);
 
             const expectedErrors = expectedResult.errors;
             assert.isTrue(expectedResult.errors.length === actualErrors.length, `Expected error: ${JSON.stringify(expectedResult.errors)}. Actual error: ${JSON.stringify(actualErrors)}.`);
@@ -20,8 +21,8 @@ namespace ts {
         }
 
         // tsconfig.json
-        it("Convert correctly format tsconfig.json to typing-options ", () => {
-            assertTypingOptions(
+        it("Convert deprecated typingOptions.enableAutoDiscovery format tsconfig.json to typeAcquisition ", () => {
+            assertTypeAcquisition(
                 {
                     "typingOptions":
                     {
@@ -32,9 +33,9 @@ namespace ts {
                 },
                 "tsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: true,
+                        enable: true,
                         include: ["0.d.ts", "1.d.ts"],
                         exclude: ["0.js", "1.js"]
                     },
@@ -42,25 +43,47 @@ namespace ts {
             });
         });
 
-        it("Convert incorrect format tsconfig.json to typing-options ", () => {
-            assertTypingOptions(
+        it("Convert correctly format tsconfig.json to typeAcquisition ", () => {
+            assertTypeAcquisition(
                 {
-                    "typingOptions":
+                    "typeAcquisition":
+                    {
+                        "enable": true,
+                        "include": ["0.d.ts", "1.d.ts"],
+                        "exclude": ["0.js", "1.js"]
+                    }
+                },
+                "tsconfig.json",
+                {
+                    typeAcquisition:
+                    {
+                        enable: true,
+                        include: ["0.d.ts", "1.d.ts"],
+                        exclude: ["0.js", "1.js"]
+                    },
+                    errors: <Diagnostic[]>[]
+            });
+        });
+
+        it("Convert incorrect format tsconfig.json to typeAcquisition ", () => {
+            assertTypeAcquisition(
+                {
+                    "typeAcquisition":
                     {
                         "enableAutoDiscovy": true,
                     }
                 }, "tsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: false,
+                        enable: false,
                         include: [],
                         exclude: []
                     },
                     errors: [
                         {
-                            category: Diagnostics.Unknown_typing_option_0.category,
-                            code: Diagnostics.Unknown_typing_option_0.code,
+                            category: Diagnostics.Unknown_type_acquisition_option_0.category,
+                            code: Diagnostics.Unknown_type_acquisition_option_0.code,
                             file: undefined,
                             start: 0,
                             length: 0,
@@ -70,12 +93,12 @@ namespace ts {
                 });
         });
 
-        it("Convert default tsconfig.json to typing-options ", () => {
-            assertTypingOptions({}, "tsconfig.json",
+        it("Convert default tsconfig.json to typeAcquisition ", () => {
+            assertTypeAcquisition({}, "tsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: false,
+                        enable: false,
                         include: [],
                         exclude: []
                     },
@@ -83,18 +106,18 @@ namespace ts {
                 });
         });
 
-        it("Convert tsconfig.json with only enableAutoDiscovery property to typing-options ", () => {
-            assertTypingOptions(
+        it("Convert tsconfig.json with only enable property to typeAcquisition ", () => {
+            assertTypeAcquisition(
                 {
-                    "typingOptions":
+                    "typeAcquisition":
                     {
-                        "enableAutoDiscovery": true
+                        "enable": true
                     }
                 }, "tsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: true,
+                        enable: true,
                         include: [],
                         exclude: []
                     },
@@ -103,20 +126,20 @@ namespace ts {
         });
 
         // jsconfig.json
-        it("Convert jsconfig.json to typing-options ", () => {
-            assertTypingOptions(
+        it("Convert jsconfig.json to typeAcquisition ", () => {
+            assertTypeAcquisition(
                 {
-                    "typingOptions":
+                    "typeAcquisition":
                     {
-                        "enableAutoDiscovery": false,
+                        "enable": false,
                         "include": ["0.d.ts"],
                         "exclude": ["0.js"]
                     }
                 }, "jsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: false,
+                        enable: false,
                         include: ["0.d.ts"],
                         exclude: ["0.js"]
                     },
@@ -124,12 +147,12 @@ namespace ts {
                 });
         });
 
-        it("Convert default jsconfig.json to typing-options ", () => {
-            assertTypingOptions({ }, "jsconfig.json",
+        it("Convert default jsconfig.json to typeAcquisition ", () => {
+            assertTypeAcquisition({ }, "jsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: true,
+                        enable: true,
                         include: [],
                         exclude: []
                     },
@@ -137,25 +160,25 @@ namespace ts {
                 });
         });
 
-        it("Convert incorrect format jsconfig.json to typing-options ", () => {
-            assertTypingOptions(
+        it("Convert incorrect format jsconfig.json to typeAcquisition ", () => {
+            assertTypeAcquisition(
                 {
-                    "typingOptions":
+                    "typeAcquisition":
                     {
                         "enableAutoDiscovy": true,
                     }
                 }, "jsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: true,
+                        enable: true,
                         include: [],
                         exclude: []
                     },
                     errors: [
                         {
                             category: Diagnostics.Unknown_compiler_option_0.category,
-                            code: Diagnostics.Unknown_typing_option_0.code,
+                            code: Diagnostics.Unknown_type_acquisition_option_0.code,
                             file: undefined,
                             start: 0,
                             length: 0,
@@ -165,18 +188,18 @@ namespace ts {
                 });
         });
 
-        it("Convert jsconfig.json with only enableAutoDiscovery property to typing-options ", () => {
-            assertTypingOptions(
+        it("Convert jsconfig.json with only enable property to typeAcquisition ", () => {
+            assertTypeAcquisition(
                 {
-                    "typingOptions":
+                    "typeAcquisition":
                     {
-                        "enableAutoDiscovery": false
+                        "enable": false
                     }
                 }, "jsconfig.json",
                 {
-                    typingOptions:
+                    typeAcquisition:
                     {
-                        enableAutoDiscovery: false,
+                        enable: false,
                         include: [],
                         exclude: []
                     },

src/harness/unittests/incrementalParser.ts

@@ -28,7 +28,7 @@ namespace ts {
         const diagnostics2 = file2.parseDiagnostics;
 
         assert.equal(diagnostics1.length, diagnostics2.length, "diagnostics1.length !== diagnostics2.length");
-        for (let i = 0, n = diagnostics1.length; i < n; i++) {
+        for (let i = 0; i < diagnostics1.length; i++) {
             const d1 = diagnostics1[i];
             const d2 = diagnostics2[i];