Merge branch 'master' into no_dom

src/compiler/binder.ts

@@ -349,17 +349,20 @@ namespace ts {
                 // Otherwise, we'll be merging into a compatible existing symbol (for example when
                 // you have multiple 'vars' with the same name in the same container).  In this case
                 // just add this node into the declarations list of the symbol.
-                symbol = symbolTable[name] || (symbolTable[name] = createSymbol(SymbolFlags.None, name));
+                symbol = symbolTable.get(name);
+                if (!symbol) {
+                    symbolTable.set(name, symbol = createSymbol(SymbolFlags.None, name));
+                }
 
                 if (name && (includes & SymbolFlags.Classifiable)) {
-                    classifiableNames[name] = name;
+                    classifiableNames.set(name, name);
                 }
 
                 if (symbol.flags & excludes) {
                     if (symbol.isReplaceableByMethod) {
                         // Javascript constructor-declared symbols can be discarded in favor of
                         // prototype symbols like methods.
-                        symbol = symbolTable[name] = createSymbol(SymbolFlags.None, name);
+                        symbolTable.set(name, symbol = createSymbol(SymbolFlags.None, name));
                     }
                     else {
                         if (node.name) {
@@ -1570,7 +1573,7 @@ namespace ts {
             const typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
             addDeclarationToSymbol(typeLiteralSymbol, node, SymbolFlags.TypeLiteral);
             typeLiteralSymbol.members = createMap<Symbol>();
-            typeLiteralSymbol.members[symbol.name] = symbol;
+            typeLiteralSymbol.members.set(symbol.name, symbol);
         }
 
         function bindObjectLiteralExpression(node: ObjectLiteralExpression) {
@@ -1601,9 +1604,9 @@ namespace ts {
                         ? ElementKind.Property
                         : ElementKind.Accessor;
 
-                    const existingKind = seen[identifier.text];
+                    const existingKind = seen.get(identifier.text);
                     if (!existingKind) {
-                        seen[identifier.text] = currentKind;
+                        seen.set(identifier.text, currentKind);
                         continue;
                     }
 
@@ -2208,7 +2211,7 @@ namespace ts {
             constructorFunction.parent = classPrototype;
             classPrototype.parent = leftSideOfAssignment;
 
-            const funcSymbol = container.locals[constructorFunction.text];
+            const funcSymbol = container.locals.get(constructorFunction.text);
             if (!funcSymbol || !(funcSymbol.flags & SymbolFlags.Function || isDeclarationOfFunctionExpression(funcSymbol))) {
                 return;
             }
@@ -2239,7 +2242,7 @@ namespace ts {
                 bindAnonymousDeclaration(node, SymbolFlags.Class, bindingName);
                 // Add name of class expression into the map for semantic classifier
                 if (node.name) {
-                    classifiableNames[node.name.text] = node.name.text;
+                    classifiableNames.set(node.name.text, node.name.text);
                 }
             }
 
@@ -2255,14 +2258,14 @@ namespace ts {
             // module might have an exported variable called 'prototype'.  We can't allow that as
             // that would clash with the built-in 'prototype' for the class.
             const prototypeSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Prototype, "prototype");
-            if (symbol.exports[prototypeSymbol.name]) {
+            const symbolExport = symbol.exports.get(prototypeSymbol.name);
+            if (symbolExport) {
                 if (node.name) {
                     node.name.parent = node;
                 }
-                file.bindDiagnostics.push(createDiagnosticForNode(symbol.exports[prototypeSymbol.name].declarations[0],
-                    Diagnostics.Duplicate_identifier_0, prototypeSymbol.name));
+                file.bindDiagnostics.push(createDiagnosticForNode(symbolExport.declarations[0], Diagnostics.Duplicate_identifier_0, prototypeSymbol.name));
             }
-            symbol.exports[prototypeSymbol.name] = prototypeSymbol;
+            symbol.exports.set(prototypeSymbol.name, prototypeSymbol);
             prototypeSymbol.parent = symbol;
         }
 

src/compiler/commandLineParser.ts

@@ -1,4 +1,4 @@
-/// <reference path="sys.ts"/>
+/// <reference path="sys.ts"/>
 /// <reference path="types.ts"/>
 /// <reference path="core.ts"/>
 /// <reference path="diagnosticInformationMap.generated.ts"/>
@@ -65,7 +65,7 @@ namespace ts {
         },
         {
             name: "jsx",
-            type: createMap({
+            type: createMapFromTemplate({
                 "preserve": JsxEmit.Preserve,
                 "react": JsxEmit.React
             }),
@@ -100,7 +100,7 @@ namespace ts {
         {
             name: "module",
             shortName: "m",
-            type: createMap({
+            type: createMapFromTemplate({
                 "none": ModuleKind.None,
                 "commonjs": ModuleKind.CommonJS,
                 "amd": ModuleKind.AMD,
@@ -114,7 +114,7 @@ namespace ts {
         },
         {
             name: "newLine",
-            type: createMap({
+            type: createMapFromTemplate({
                 "crlf": NewLineKind.CarriageReturnLineFeed,
                 "lf": NewLineKind.LineFeed
             }),
@@ -263,7 +263,7 @@ namespace ts {
         {
             name: "target",
             shortName: "t",
-            type: createMap({
+            type: createMapFromTemplate({
                 "es3": ScriptTarget.ES3,
                 "es5": ScriptTarget.ES5,
                 "es6": ScriptTarget.ES2015,
@@ -300,7 +300,7 @@ namespace ts {
         },
         {
             name: "moduleResolution",
-            type: createMap({
+            type: createMapFromTemplate({
                 "node": ModuleResolutionKind.NodeJs,
                 "classic": ModuleResolutionKind.Classic,
             }),
@@ -409,7 +409,7 @@ namespace ts {
             type: "list",
             element: {
                 name: "lib",
-                type: createMap({
+                type: createMapFromTemplate({
                     // JavaScript only
                     "es5": "lib.es5.d.ts",
                     "es6": "lib.es2015.d.ts",
@@ -531,9 +531,9 @@ namespace ts {
         const optionNameMap = createMap<CommandLineOption>();
         const shortOptionNames = createMap<string>();
         forEach(optionDeclarations, option => {
-            optionNameMap[option.name.toLowerCase()] = option;
+            optionNameMap.set(option.name.toLowerCase(), option);
             if (option.shortName) {
-                shortOptionNames[option.shortName] = option.name;
+                shortOptionNames.set(option.shortName, option.name);
             }
         });
 
@@ -543,7 +543,7 @@ namespace ts {
 
     /* @internal */
     export function createCompilerDiagnosticForInvalidCustomType(opt: CommandLineOptionOfCustomType): Diagnostic {
-        const namesOfType = Object.keys(opt.type).map(key => `'${key}'`).join(", ");
+        const namesOfType = arrayFrom(opt.type.keys()).map(key => `'${key}'`).join(", ");
         return createCompilerDiagnostic(Diagnostics.Argument_for_0_option_must_be_Colon_1, `--${opt.name}`, namesOfType);
     }
 
@@ -597,13 +597,13 @@ namespace ts {
                     s = s.slice(s.charCodeAt(1) === CharacterCodes.minus ? 2 : 1).toLowerCase();
 
                     // Try to translate short option names to their full equivalents.
-                    if (s in shortOptionNames) {
-                        s = shortOptionNames[s];
+                    const short = shortOptionNames.get(s);
+                    if (short !== undefined) {
+                        s = short;
                     }
 
-                    if (s in optionNameMap) {
-                        const opt = optionNameMap[s];
-
+                    const opt = optionNameMap.get(s);
+                    if (opt) {
                         if (opt.isTSConfigOnly) {
                             errors.push(createCompilerDiagnostic(Diagnostics.Option_0_can_only_be_specified_in_tsconfig_json_file, opt.name));
                         }
@@ -726,7 +726,7 @@ namespace ts {
      * @param fileNames array of filenames to be generated into tsconfig.json
      */
     /* @internal */
-    export function generateTSConfig(options: CompilerOptions, fileNames: string[]): { compilerOptions: Map<CompilerOptionsValue> } {
+    export function generateTSConfig(options: CompilerOptions, fileNames: string[]): { compilerOptions: MapLike<CompilerOptionsValue> } {
         const compilerOptions = extend(options, defaultInitCompilerOptions);
         const configurations: any = {
             compilerOptions: serializeCompilerOptions(compilerOptions)
@@ -751,18 +751,17 @@ namespace ts {
             }
         }
 
-        function getNameOfCompilerOptionValue(value: CompilerOptionsValue, customTypeMap: MapLike<string | number>): string | undefined {
+        function getNameOfCompilerOptionValue(value: CompilerOptionsValue, customTypeMap: Map<string | number>): string | undefined {
             // There is a typeMap associated with this command-line option so use it to map value back to its name
-            for (const key in customTypeMap) {
-                if (customTypeMap[key] === value) {
+            return forEachEntry(customTypeMap, (mapValue, key) => {
+                if (mapValue === value) {
                     return key;
                 }
-            }
-            return undefined;
+            });
         }
 
-        function serializeCompilerOptions(options: CompilerOptions): Map<CompilerOptionsValue> {
-            const result = createMap<CompilerOptionsValue>();
+        function serializeCompilerOptions(options: CompilerOptions): MapLike<CompilerOptionsValue> {
+            const result: ts.MapLike<CompilerOptionsValue> = {};
             const optionsNameMap = getOptionNameMap().optionNameMap;
 
             for (const name in options) {
@@ -778,7 +777,7 @@ namespace ts {
                             break;
                         default:
                             const value = options[name];
-                            const optionDefinition = optionsNameMap[name.toLowerCase()];
+                            const optionDefinition = optionsNameMap.get(name.toLowerCase());
                             if (optionDefinition) {
                                 const customTypeMap = getCustomTypeMapOfCommandLineOption(optionDefinition);
                                 if (!customTypeMap) {
@@ -1049,8 +1048,8 @@ namespace ts {
         const optionNameMap = arrayToMap(optionDeclarations, opt => opt.name);
 
         for (const id in jsonOptions) {
-            if (id in optionNameMap) {
-                const opt = optionNameMap[id];
+            const opt = optionNameMap.get(id);
+            if (opt) {
                 defaultOptions[opt.name] = convertJsonOption(opt, jsonOptions[id], basePath, errors);
             }
             else {
@@ -1086,8 +1085,9 @@ namespace ts {
 
     function convertJsonOptionOfCustomType(opt: CommandLineOptionOfCustomType, value: string, errors: Diagnostic[]) {
         const key = value.toLowerCase();
-        if (key in opt.type) {
-            return opt.type[key];
+        const val = opt.type.get(key);
+        if (val !== undefined) {
+            return val;
         }
         else {
             errors.push(createCompilerDiagnosticForInvalidCustomType(opt));
@@ -1215,7 +1215,7 @@ namespace ts {
         // file map that marks whether it was a regular wildcard match (with a `*` or `?` token),
         // or a recursive directory. This information is used by filesystem watchers to monitor for
         // new entries in these paths.
-        const wildcardDirectories: Map<WatchDirectoryFlags> = getWildcardDirectories(include, exclude, basePath, host.useCaseSensitiveFileNames);
+        const wildcardDirectories = getWildcardDirectories(include, exclude, basePath, host.useCaseSensitiveFileNames);
 
         // Rather than requery this for each file and filespec, we query the supported extensions
         // once and store it on the expansion context.
@@ -1226,7 +1226,7 @@ namespace ts {
         if (fileNames) {
             for (const fileName of fileNames) {
                 const file = combinePaths(basePath, fileName);
-                literalFileMap[keyMapper(file)] = file;
+                literalFileMap.set(keyMapper(file), file);
             }
         }
 
@@ -1249,14 +1249,14 @@ namespace ts {
                 removeWildcardFilesWithLowerPriorityExtension(file, wildcardFileMap, supportedExtensions, keyMapper);
 
                 const key = keyMapper(file);
-                if (!(key in literalFileMap) && !(key in wildcardFileMap)) {
-                    wildcardFileMap[key] = file;
+                if (!literalFileMap.has(key) && !wildcardFileMap.has(key)) {
+                    wildcardFileMap.set(key, file);
                 }
             }
         }
 
-        const literalFiles = reduceProperties(literalFileMap, addFileToOutput, []);
-        const wildcardFiles = reduceProperties(wildcardFileMap, addFileToOutput, []);
+        const literalFiles = arrayFrom(literalFileMap.values());
+        const wildcardFiles = arrayFrom(wildcardFileMap.values());
         wildcardFiles.sort(host.useCaseSensitiveFileNames ? compareStrings : compareStringsCaseInsensitive);
         return {
             fileNames: literalFiles.concat(wildcardFiles),
@@ -1287,7 +1287,7 @@ namespace ts {
     /**
      * Gets directories in a set of include patterns that should be watched for changes.
      */
-    function getWildcardDirectories(include: string[], exclude: string[], path: string, useCaseSensitiveFileNames: boolean): Map<WatchDirectoryFlags> {
+    function getWildcardDirectories(include: string[], exclude: string[], path: string, useCaseSensitiveFileNames: boolean): MapLike<WatchDirectoryFlags> {
         // We watch a directory recursively if it contains a wildcard anywhere in a directory segment
         // of the pattern:
         //
@@ -1302,7 +1302,7 @@ namespace ts {
         //  /a/b/a?z    - Watch /a/b directly to catch any new file matching a?z
         const rawExcludeRegex = getRegularExpressionForWildcard(exclude, path, "exclude");
         const excludeRegex = rawExcludeRegex && new RegExp(rawExcludeRegex, useCaseSensitiveFileNames ? "" : "i");
-        const wildcardDirectories = createMap<WatchDirectoryFlags>();
+        const wildcardDirectories: ts.MapLike<WatchDirectoryFlags> = {};
         if (include !== undefined) {
             const recursiveKeys: string[] = [];
             for (const file of include) {
@@ -1325,13 +1325,13 @@ namespace ts {
             }
 
             // Remove any subpaths under an existing recursively watched directory.
-            for (const key in wildcardDirectories) {
+            for (const key in wildcardDirectories) if (hasProperty(wildcardDirectories, key)) {
                 for (const recursiveKey of recursiveKeys) {
                     if (key !== recursiveKey && containsPath(recursiveKey, key, path, !useCaseSensitiveFileNames)) {
                         delete wildcardDirectories[key];
                     }
                 }
-            }
+            };
         }
 
         return wildcardDirectories;
@@ -1365,7 +1365,7 @@ namespace ts {
         for (let i = ExtensionPriority.Highest; i < adjustedExtensionPriority; i++) {
             const higherPriorityExtension = extensions[i];
             const higherPriorityPath = keyMapper(changeExtension(file, higherPriorityExtension));
-            if (higherPriorityPath in literalFiles || higherPriorityPath in wildcardFiles) {
+            if (literalFiles.has(higherPriorityPath) || wildcardFiles.has(higherPriorityPath)) {
                 return true;
             }
         }
@@ -1387,21 +1387,10 @@ namespace ts {
         for (let i = nextExtensionPriority; i < extensions.length; i++) {
             const lowerPriorityExtension = extensions[i];
             const lowerPriorityPath = keyMapper(changeExtension(file, lowerPriorityExtension));
-            delete wildcardFiles[lowerPriorityPath];
+            wildcardFiles.delete(lowerPriorityPath);
         }
     }
 
-    /**
-     * Adds a file to an array of files.
-     *
-     * @param output The output array.
-     * @param file The file path.
-     */
-    function addFileToOutput(output: string[], file: string) {
-        output.push(file);
-        return output;
-    }
-
     /**
      * Gets a case sensitive key.
      *

src/compiler/core.ts

@@ -23,13 +23,12 @@ namespace ts {
         True = -1
     }
 
-    const createObject = Object.create;
-
     // More efficient to create a collator once and use its `compare` than to call `a.localeCompare(b)` many times.
     export const collator: { compare(a: string, b: string): number } = typeof Intl === "object" && typeof Intl.Collator === "function" ? new Intl.Collator() : undefined;
 
-    export function createMap<T>(template?: MapLike<T>): Map<T> {
-        const map: Map<T> = createObject(null); // tslint:disable-line:no-null-keyword
+    /** Create a MapLike with good performance. */
+    function createDictionaryObject<T>(): MapLike<T> {
+        const map = Object.create(null); // tslint:disable-line:no-null-keyword
 
         // Using 'delete' on an object causes V8 to put the object in dictionary mode.
         // This disables creation of hidden classes, which are expensive when an object is
@@ -37,17 +36,113 @@ namespace ts {
         map["__"] = undefined;
         delete map["__"];
 
+        return map;
+    }
+
+    /** Create a new map. If a template object is provided, the map will copy entries from it. */
+    export function createMap<T>(): Map<T> {
+        return new MapCtr<T>();
+    }
+
+    export function createMapFromTemplate<T>(template?: MapLike<T>): Map<T> {
+        const map: Map<T> = new MapCtr<T>();
+
         // Copies keys/values from template. Note that for..in will not throw if
         // template is undefined, and instead will just exit the loop.
         for (const key in template) if (hasOwnProperty.call(template, key)) {
-            map[key] = template[key];
+            map.set(key, template[key]);
         }
 
         return map;
     }
 
+    // The global Map object. This may not be available, so we must test for it.
+    declare const Map: { new<T>(): Map<T> } | undefined;
+    // Internet Explorer's Map doesn't support iteration, so don't use it.
+    // tslint:disable-next-line:no-in-operator
+    const MapCtr = typeof Map !== "undefined" && "entries" in Map.prototype ? Map : shimMap();
+
+    // Keep the class inside a function so it doesn't get compiled if it's not used.
+    function shimMap(): { new<T>(): Map<T> } {
+
+        class MapIterator<T, U extends (string | T | [string, T])> {
+            private data: MapLike<T>;
+            private keys: string[];
+            private index = 0;
+            private selector: (data: MapLike<T>, key: string) => U;
+            constructor(data: MapLike<T>, selector: (data: MapLike<T>, key: string) => U) {
+                this.data = data;
+                this.selector = selector;
+                this.keys = Object.keys(data);
+            }
+
+            public next(): { value: U, done: false } | { value: never, done: true } {
+                const index = this.index;
+                if (index < this.keys.length) {
+                    this.index++;
+                    return { value: this.selector(this.data, this.keys[index]), done: false };
+                }
+                return { value: undefined as never, done: true }
+            }
+        }
+
+        return class<T> implements Map<T> {
+            private data = createDictionaryObject<T>();
+            public size = 0;
+
+            get(key: string): T {
+                return this.data[key];
+            }
+
+            set(key: string, value: T): this {
+                if (!this.has(key)) {
+                    this.size++;
+                }
+                this.data[key] = value;
+                return this;
+            }
+
+            has(key: string): boolean {
+                // tslint:disable-next-line:no-in-operator
+                return key in this.data;
+            }
+
+            delete(key: string): boolean {
+                if (this.has(key)) {
+                    this.size--;
+                    delete this.data[key];
+                    return true;
+                }
+                return false;
+            }
+
+            clear(): void {
+                this.data = createDictionaryObject<T>();
+                this.size = 0;
+            }
+
+            keys() {
+                return new MapIterator(this.data, (_data, key) => key);
+            }
+
+            values() {
+                return new MapIterator(this.data, (data, key) => data[key]);
+            }
+
+            entries() {
+                return new MapIterator(this.data, (data, key) => [key, data[key]] as [string, T]);
+            }
+
+            forEach(action: (value: T, key: string) => void): void {
+                for (const key in this.data) {
+                    action(this.data[key], key);
+                }
+            }
+        }
+    }
+
     export function createFileMap<T>(keyMapper?: (key: string) => string): FileMap<T> {
-        let files = createMap<T>();
+        const files = createMap<T>();
         return {
             get,
             set,
@@ -59,39 +154,34 @@ namespace ts {
         };
 
         function forEachValueInMap(f: (key: Path, value: T) => void) {
-            for (const key in files) {
-                f(<Path>key, files[key]);
-            }
+            files.forEach((file, key) => {
+                f(<Path>key, file);
+            });
         }
 
         function getKeys() {
-            const keys: Path[] = [];
-            for (const key in files) {
-                keys.push(<Path>key);
-            }
-            return keys;
+            return arrayFrom(files.keys()) as Path[];
         }
 
         // path should already be well-formed so it does not need to be normalized
         function get(path: Path): T {
-            return files[toKey(path)];
+            return files.get(toKey(path));
         }
 
         function set(path: Path, value: T) {
-            files[toKey(path)] = value;
+            files.set(toKey(path), value);
         }
 
         function contains(path: Path) {
-            return toKey(path) in files;
+            return files.has(toKey(path));
         }
 
         function remove(path: Path) {
-            const key = toKey(path);
-            delete files[key];
+            files.delete(toKey(path));
         }
 
         function clear() {
-            files = createMap<T>();
+            files.clear();
         }
 
         function toKey(path: Path): string {
@@ -420,17 +510,16 @@ namespace ts {
         return result;
     }
 
-    export function mapObject<T, U>(object: MapLike<T>, f: (key: string, x: T) => [string, U]): MapLike<U> {
-        let result: MapLike<U>;
-        if (object) {
-            result = {};
-            for (const v of getOwnKeys(object)) {
-                const [key, value]: [string, U] = f(v, object[v]) || [undefined, undefined];
-                if (key !== undefined) {
-                    result[key] = value;
-                }
-            }
+    export function mapEntries<T, U>(map: Map<T>, f: (key: string, value: T) => [string, U]): Map<U> {
+        if (!map) {
+            return undefined;
         }
+
+        const result = createMap<U>();
+        map.forEach((value, key) => {
+            const [newKey, newValue] = f(key, value);
+            result.set(newKey, newValue);
+        });
         return result;
     }
 
@@ -748,9 +837,6 @@ namespace ts {
     /**
      * Indicates whether a map-like contains an own property with the specified key.
      *
-     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
-     *       the 'in' operator.
-     *
      * @param map A map-like.
      * @param key A property key.
      */
@@ -761,9 +847,6 @@ namespace ts {
     /**
      * Gets the value of an owned property in a map-like.
      *
-     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
-     *       an indexer.
-     *
      * @param map A map-like.
      * @param key A property key.
      */
@@ -787,50 +870,48 @@ namespace ts {
         return keys;
     }
 
-    /**
-     * Enumerates the properties of a Map<T>, invoking a callback and returning the first truthy result.
-     *
-     * @param map A map for which properties should be enumerated.
-     * @param callback A callback to invoke for each property.
-     */
-    export function forEachProperty<T, U>(map: Map<T>, callback: (value: T, key: string) => U): U {
-        let result: U;
-        for (const key in map) {
-            if (result = callback(map[key], key)) break;
+    /** Shims `Array.from`. */
+    export function arrayFrom<T>(iterator: Iterator<T>): T[] {
+        const result: T[] = [];
+        for (let { value, done } = iterator.next(); !done; { value, done } = iterator.next()) {
+            result.push(value);
         }
         return result;
     }
 
     /**
-     * Returns true if a Map<T> has some matching property.
-     *
-     * @param map A map whose properties should be tested.
-     * @param predicate An optional callback used to test each property.
+     * Calls `callback` for each entry in the map, returning the first truthy result.
+     * Use `map.forEach` instead for normal iteration.
      */
-    export function someProperties<T>(map: Map<T>, predicate?: (value: T, key: string) => boolean) {
-        for (const key in map) {
-            if (!predicate || predicate(map[key], key)) return true;
+    export function forEachEntry<T, U>(map: Map<T>, callback: (value: T, key: string) => U | undefined): U | undefined {
+        const iterator = map.entries();
+        for (let { value: pair, done } = iterator.next(); !done; { value: pair, done } = iterator.next()) {
+            const [key, value] = pair;
+            const result = callback(value, key);
+            if (result) {
+                return result;
+            }
         }
-        return false;
+        return undefined;
     }
 
-    /**
-     * Performs a shallow copy of the properties from a source Map<T> to a target MapLike<T>
-     *
-     * @param source A map from which properties should be copied.
-     * @param target A map to which properties should be copied.
-     */
-    export function copyProperties<T>(source: Map<T>, target: MapLike<T>): void {
-        for (const key in source) {
-            target[key] = source[key];
+    /** `forEachEntry` for just keys. */
+    export function forEachKey<T>(map: Map<{}>, callback: (key: string) => T | undefined): T | undefined {
+        const iterator = map.keys();
+        for (let { value: key, done } = iterator.next(); !done; { value: key, done } = iterator.next()) {
+            const result = callback(key);
+            if (result) {
+                return result;
+            }
         }
+        return undefined;
     }
 
-    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;
+    /** Copy entries from `source` to `target`. */
+    export function copyEntries<T>(source: Map<T>, target: Map<T>): void {
+        source.forEach((value, key) => {
+            target.set(key, value);
+        });
     }
 
     export function assign<T1 extends MapLike<{}>, T2, T3>(t: T1, arg1: T2, arg2: T3): T1 & T2 & T3;
@@ -845,24 +926,6 @@ namespace ts {
         return t;
     }
 
-    /**
-     * Reduce the properties of a map.
-     *
-     * NOTE: This is intended for use with Map<T> objects. For MapLike<T> objects, use
-     *       reduceOwnProperties instead as it offers better runtime safety.
-     *
-     * @param map The map 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 reduceProperties<T, U>(map: Map<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
-        let result = initial;
-        for (const key in map) {
-            result = callback(result, map[key], String(key));
-        }
-        return result;
-    }
-
     /**
      * Performs a shallow equality comparison of the contents of two map-likes.
      *
@@ -897,23 +960,14 @@ namespace ts {
     export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue?: (value: T) => U): Map<T | U> {
         const result = createMap<T | U>();
         for (const value of array) {
-            result[makeKey(value)] = makeValue ? makeValue(value) : value;
+            result.set(makeKey(value), makeValue ? makeValue(value) : value);
         }
         return result;
     }
 
-    export function isEmpty<T>(map: Map<T>) {
-        for (const id in map) {
-            if (hasProperty(map, id)) {
-                return false;
-            }
-        }
-        return true;
-    }
-
     export function cloneMap<T>(map: Map<T>) {
         const clone = createMap<T>();
-        copyProperties(map, clone);
+        copyEntries(map, clone);
         return clone;
     }
 
@@ -938,32 +992,43 @@ namespace ts {
         return result;
     }
 
-    /**
-     * Adds the value to an array of values associated with the key, and returns the array.
-     * Creates the array if it does not already exist.
-     */
-    export function multiMapAdd<V>(map: Map<V[]>, key: string | number, value: V): V[] {
-        const values = map[key];
-        if (values) {
-            values.push(value);
-            return values;
-        }
-        else {
-            return map[key] = [value];
-        }
+    export interface MultiMap<T> extends Map<T[]> {
+        /**
+         * Adds the value to an array of values associated with the key, and returns the array.
+         * Creates the array if it does not already exist.
+         */
+        add(key: string, value: T): T[];
+        /**
+         * Removes a value from an array of values associated with the key.
+         * Does not preserve the order of those values.
+         * Does nothing if `key` is not in `map`, or `value` is not in `map[key]`.
+         */
+        remove(key: string, value: T): void;
     }
 
-    /**
-     * Removes a value from an array of values associated with the key.
-     * Does not preserve the order of those values.
-     * Does nothing if `key` is not in `map`, or `value` is not in `map[key]`.
-     */
-    export function multiMapRemove<V>(map: Map<V[]>, key: string, value: V): void {
-        const values = map[key];
+    export function createMultiMap<T>(): MultiMap<T> {
+        const map = createMap<T[]>() as MultiMap<T>;
+        map.add = multiMapAdd;
+        map.remove = multiMapRemove;
+        return map;
+    }
+    function multiMapAdd<T>(this: MultiMap<T>, key: string, value: T) {
+        let values = this.get(key);
+        if (values) {
+            values.push(value);
+        }
+        else {
+            this.set(key, values = [value]);
+        }
+        return values;
+
+    }
+    function multiMapRemove<T>(this: MultiMap<T>, key: string, value: T) {
+        const values = this.get(key);
         if (values) {
             unorderedRemoveItem(values, value);
             if (!values.length) {
-                delete map[key];
+                this.delete(key);
             }
         }
     }
@@ -1066,7 +1131,7 @@ namespace ts {
         return text.replace(/{(\d+)}/g, (_match, index?) => args[+index + baseIndex]);
     }
 
-    export let localizedDiagnosticMessages: Map<string> = undefined;
+    export let localizedDiagnosticMessages: MapLike<string> = undefined;
 
     export function getLocaleSpecificMessage(message: DiagnosticMessage) {
         return localizedDiagnosticMessages && localizedDiagnosticMessages[message.key] || message.message;

src/compiler/declarationEmitter.ts

@@ -156,9 +156,9 @@ namespace ts {
         });
 
         if (usedTypeDirectiveReferences) {
-            for (const directive in usedTypeDirectiveReferences) {
+            forEachKey(usedTypeDirectiveReferences, directive => {
                 referencesOutput += `/// <reference types="${directive}" />${newLine}`;
-            }
+            });
         }
 
         return {
@@ -271,8 +271,8 @@ namespace ts {
                 usedTypeDirectiveReferences = createMap<string>();
             }
             for (const directive of typeReferenceDirectives) {
-                if (!(directive in usedTypeDirectiveReferences)) {
-                    usedTypeDirectiveReferences[directive] = directive;
+                if (!usedTypeDirectiveReferences.has(directive)) {
+                    usedTypeDirectiveReferences.set(directive, directive);
                 }
             }
         }
@@ -390,6 +390,7 @@ namespace ts {
                 case SyntaxKind.StringKeyword:
                 case SyntaxKind.NumberKeyword:
                 case SyntaxKind.BooleanKeyword:
+                case SyntaxKind.ObjectKeyword:
                 case SyntaxKind.SymbolKeyword:
                 case SyntaxKind.VoidKeyword:
                 case SyntaxKind.UndefinedKeyword:
@@ -581,14 +582,14 @@ namespace ts {
         // do not need to keep track of created temp names.
         function getExportDefaultTempVariableName(): string {
             const baseName = "_default";
-            if (!(baseName in currentIdentifiers)) {
+            if (!currentIdentifiers.has(baseName)) {
                 return baseName;
             }
             let count = 0;
             while (true) {
                 count++;
                 const name = baseName + "_" + count;
-                if (!(name in currentIdentifiers)) {
+                if (!currentIdentifiers.has(name)) {
                     return name;
                 }
             }

src/compiler/diagnosticMessages.json

@@ -2015,6 +2015,10 @@
         "category": "Error",
         "code": 2698
     },
+    "Static property '{0}' conflicts with built-in property 'Function.{0}' of constructor function '{1}'.": {
+        "category": "Error",
+        "code": 2699
+    },
     "Rest types may only be created from object types.": {
         "category": "Error",
         "code": 2700

src/compiler/emitter.ts

@@ -2043,11 +2043,11 @@ namespace ts {
                         // 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]) {
+                            if (bundledHelpers.get(helper.name)) {
                                 continue;
                             }
 
-                            bundledHelpers[helper.name] = true;
+                            bundledHelpers.set(helper.name, true);
                         }
                     }
                     else if (isBundle) {
@@ -2508,15 +2508,16 @@ namespace ts {
 
         function isUniqueName(name: string): boolean {
             return !resolver.hasGlobalName(name) &&
-                !hasProperty(currentFileIdentifiers, name) &&
-                !hasProperty(generatedNameSet, name);
+                !currentFileIdentifiers.has(name) &&
+                !generatedNameSet.has(name);
         }
 
         function isUniqueLocalName(name: string, container: Node): boolean {
             for (let node = container; isNodeDescendantOf(node, container); node = node.nextContainer) {
-                if (node.locals && hasProperty(node.locals, name)) {
+                if (node.locals) {
+                    const local = node.locals.get(name);
                     // We conservatively include alias symbols to cover cases where they're emitted as locals
-                    if (node.locals[name].flags & (SymbolFlags.Value | SymbolFlags.ExportValue | SymbolFlags.Alias)) {
+                    if (local && local.flags & (SymbolFlags.Value | SymbolFlags.ExportValue | SymbolFlags.Alias)) {
                         return false;
                     }
                 }
@@ -2565,7 +2566,8 @@ namespace ts {
             while (true) {
                 const generatedName = baseName + i;
                 if (isUniqueName(generatedName)) {
-                    return generatedNameSet[generatedName] = generatedName;
+                    generatedNameSet.set(generatedName, generatedName);
+                    return generatedName;
                 }
                 i++;
             }

src/compiler/factory.ts

@@ -1,4 +1,4 @@
-/// <reference path="core.ts"/>
+/// <reference path="core.ts"/>
 /// <reference path="utilities.ts"/>
 
 /* @internal */
@@ -2646,9 +2646,11 @@ namespace ts {
         return destEmitNode;
     }
 
-    function mergeTokenSourceMapRanges(sourceRanges: Map<TextRange>, destRanges: Map<TextRange>) {
-        if (!destRanges) destRanges = createMap<TextRange>();
-        copyProperties(sourceRanges, destRanges);
+    function mergeTokenSourceMapRanges(sourceRanges: TextRange[], destRanges: TextRange[]) {
+        if (!destRanges) destRanges = [];
+        for (const key in sourceRanges) {
+            destRanges[key] = sourceRanges[key];
+        }
         return destRanges;
     }
 
@@ -2762,7 +2764,7 @@ namespace ts {
      */
     export function setTokenSourceMapRange<T extends Node>(node: T, token: SyntaxKind, range: TextRange) {
         const emitNode = getOrCreateEmitNode(node);
-        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = createMap<TextRange>());
+        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = []);
         tokenSourceMapRanges[token] = range;
         return node;
     }
@@ -2974,10 +2976,8 @@ namespace ts {
      * Here we check if alternative name was provided for a given moduleName and return it if possible.
      */
     function tryRenameExternalModule(moduleName: LiteralExpression, sourceFile: SourceFile) {
-        if (sourceFile.renamedDependencies && hasProperty(sourceFile.renamedDependencies, moduleName.text)) {
-            return createLiteral(sourceFile.renamedDependencies[moduleName.text]);
-        }
-        return undefined;
+        const rename = sourceFile.renamedDependencies && sourceFile.renamedDependencies.get(moduleName.text);
+        return rename && createLiteral(rename);
     }
 
     /**
@@ -3277,7 +3277,7 @@ namespace ts {
         externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]; // imports of other external modules
         externalHelpersImportDeclaration: ImportDeclaration | undefined; // import of external helpers
         exportSpecifiers: Map<ExportSpecifier[]>; // export specifiers by name
-        exportedBindings: Map<Identifier[]>; // exported names of local declarations
+        exportedBindings: Identifier[][]; // exported names of local declarations
         exportedNames: Identifier[]; // all exported names local to module
         exportEquals: ExportAssignment | undefined; // an export= declaration if one was present
         hasExportStarsToExportValues: boolean; // whether this module contains export*
@@ -3285,8 +3285,8 @@ namespace ts {
 
     export function collectExternalModuleInfo(sourceFile: SourceFile, resolver: EmitResolver, compilerOptions: CompilerOptions): ExternalModuleInfo {
         const externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[] = [];
-        const exportSpecifiers = createMap<ExportSpecifier[]>();
-        const exportedBindings = createMap<Identifier[]>();
+        const exportSpecifiers = createMultiMap<ExportSpecifier>();
+        const exportedBindings: Identifier[][] = [];
         const uniqueExports = createMap<boolean>();
         let exportedNames: Identifier[];
         let hasExportDefault = false;
@@ -3337,18 +3337,18 @@ namespace ts {
                     else {
                         // export { x, y }
                         for (const specifier of (<ExportDeclaration>node).exportClause.elements) {
-                            if (!uniqueExports[specifier.name.text]) {
+                            if (!uniqueExports.get(specifier.name.text)) {
                                 const name = specifier.propertyName || specifier.name;
-                                multiMapAdd(exportSpecifiers, name.text, specifier);
+                                exportSpecifiers.add(name.text, specifier);
 
                                 const decl = resolver.getReferencedImportDeclaration(name)
                                     || resolver.getReferencedValueDeclaration(name);
 
                                 if (decl) {
-                                    multiMapAdd(exportedBindings, getOriginalNodeId(decl), specifier.name);
+                                    multiMapSparseArrayAdd(exportedBindings, getOriginalNodeId(decl), specifier.name);
                                 }
 
-                                uniqueExports[specifier.name.text] = true;
+                                uniqueExports.set(specifier.name.text, true);
                                 exportedNames = append(exportedNames, specifier.name);
                             }
                         }
@@ -3375,16 +3375,16 @@ namespace ts {
                         if (hasModifier(node, ModifierFlags.Default)) {
                             // export default function() { }
                             if (!hasExportDefault) {
-                                multiMapAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<FunctionDeclaration>node));
+                                multiMapSparseArrayAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<FunctionDeclaration>node));
                                 hasExportDefault = true;
                             }
                         }
                         else {
                             // export function x() { }
                             const name = (<FunctionDeclaration>node).name;
-                            if (!uniqueExports[name.text]) {
-                                multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
-                                uniqueExports[name.text] = true;
+                            if (!uniqueExports.get(name.text)) {
+                                multiMapSparseArrayAdd(exportedBindings, getOriginalNodeId(node), name);
+                                uniqueExports.set(name.text, true);
                                 exportedNames = append(exportedNames, name);
                             }
                         }
@@ -3396,16 +3396,16 @@ namespace ts {
                         if (hasModifier(node, ModifierFlags.Default)) {
                             // export default class { }
                             if (!hasExportDefault) {
-                                multiMapAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<ClassDeclaration>node));
+                                multiMapSparseArrayAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<ClassDeclaration>node));
                                 hasExportDefault = true;
                             }
                         }
                         else {
                             // export class x { }
                             const name = (<ClassDeclaration>node).name;
-                            if (!uniqueExports[name.text]) {
-                                multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
-                                uniqueExports[name.text] = true;
+                            if (!uniqueExports.get(name.text)) {
+                                multiMapSparseArrayAdd(exportedBindings, getOriginalNodeId(node), name);
+                                uniqueExports.set(name.text, true);
                                 exportedNames = append(exportedNames, name);
                             }
                         }
@@ -3426,11 +3426,23 @@ namespace ts {
             }
         }
         else if (!isGeneratedIdentifier(decl.name)) {
-            if (!uniqueExports[decl.name.text]) {
-                uniqueExports[decl.name.text] = true;
+            if (!uniqueExports.get(decl.name.text)) {
+                uniqueExports.set(decl.name.text, true);
                 exportedNames = append(exportedNames, decl.name);
             }
         }
         return exportedNames;
     }
+
+    /** Use a sparse array as a multi-map. */
+    function multiMapSparseArrayAdd<V>(map: V[][], key: number, value: V): V[] {
+        let values = map[key];
+        if (values) {
+            values.push(value);
+        }
+        else {
+            map[key] = values = [value];
+        }
+        return values;
+    }
 }

src/compiler/moduleNameResolver.ts

@@ -336,9 +336,10 @@ namespace ts {
             if (!moduleHasNonRelativeName(nonRelativeModuleName)) {
                 return undefined;
             }
-            let perModuleNameCache = moduleNameToDirectoryMap[nonRelativeModuleName];
+            let perModuleNameCache = moduleNameToDirectoryMap.get(nonRelativeModuleName);
             if (!perModuleNameCache) {
-                moduleNameToDirectoryMap[nonRelativeModuleName] = perModuleNameCache = createPerModuleNameCache();
+                perModuleNameCache = createPerModuleNameCache();
+                moduleNameToDirectoryMap.set(nonRelativeModuleName, perModuleNameCache);
             }
             return perModuleNameCache;
         }
@@ -422,7 +423,7 @@ namespace ts {
         }
         const containingDirectory = getDirectoryPath(containingFile);
         const perFolderCache = cache && cache.getOrCreateCacheForDirectory(containingDirectory);
-        let result = perFolderCache && perFolderCache[moduleName];
+        let result = perFolderCache && perFolderCache.get(moduleName);
 
         if (result) {
             if (traceEnabled) {
@@ -453,7 +454,7 @@ namespace ts {
             }
 
             if (perFolderCache) {
-                perFolderCache[moduleName] = result;
+                perFolderCache.set(moduleName, result);
                 // put result in per-module name cache
                 const perModuleNameCache = cache.getOrCreateCacheForModuleName(moduleName);
                 if (perModuleNameCache) {

src/compiler/parser.ts

@@ -1134,7 +1134,11 @@ namespace ts {
 
         function internIdentifier(text: string): string {
             text = escapeIdentifier(text);
-            return identifiers[text] || (identifiers[text] = text);
+            let identifier = identifiers.get(text);
+            if (identifier === undefined) {
+                identifiers.set(text, identifier = text);
+            }
+            return identifier;
         }
 
         // An identifier that starts with two underscores has an extra underscore character prepended to it to avoid issues

src/compiler/performance.ts

@@ -27,8 +27,8 @@ namespace ts.performance {
      */
     export function mark(markName: string) {
         if (enabled) {
-            marks[markName] = timestamp();
-            counts[markName] = (counts[markName] || 0) + 1;
+            marks.set(markName, timestamp());
+            counts.set(markName, (counts.get(markName) || 0) + 1);
             profilerEvent(markName);
         }
     }
@@ -44,9 +44,9 @@ namespace ts.performance {
      */
     export function measure(measureName: string, startMarkName?: string, endMarkName?: string) {
         if (enabled) {
-            const end = endMarkName && marks[endMarkName] || timestamp();
-            const start = startMarkName && marks[startMarkName] || profilerStart;
-            measures[measureName] = (measures[measureName] || 0) + (end - start);
+            const end = endMarkName && marks.get(endMarkName) || timestamp();
+            const start = startMarkName && marks.get(startMarkName) || profilerStart;
+            measures.set(measureName, (measures.get(measureName) || 0) + (end - start));
         }
     }
 
@@ -56,7 +56,7 @@ namespace ts.performance {
      * @param markName The name of the mark.
      */
     export function getCount(markName: string) {
-        return counts && counts[markName] || 0;
+        return counts && counts.get(markName) || 0;
     }
 
     /**
@@ -65,7 +65,7 @@ namespace ts.performance {
      * @param measureName The name of the measure whose durations should be accumulated.
      */
     export function getDuration(measureName: string) {
-        return measures && measures[measureName] || 0;
+        return measures && measures.get(measureName) || 0;
     }
 
     /**
@@ -74,9 +74,9 @@ namespace ts.performance {
      * @param cb The action to perform for each measure
      */
     export function forEachMeasure(cb: (measureName: string, duration: number) => void) {
-        for (const key in measures) {
-            cb(key, measures[key]);
-        }
+        measures.forEach((measure, key) => {
+            cb(key, measure);
+        });
     }
 
     /** Enables (and resets) performance measurements for the compiler. */

src/compiler/program.ts

@@ -111,11 +111,11 @@ namespace ts {
         }
 
         function directoryExists(directoryPath: string): boolean {
-            if (directoryPath in existingDirectories) {
+            if (existingDirectories.has(directoryPath)) {
                 return true;
             }
             if (sys.directoryExists(directoryPath)) {
-                existingDirectories[directoryPath] = true;
+                existingDirectories.set(directoryPath, true);
                 return true;
             }
             return false;
@@ -139,11 +139,11 @@ namespace ts {
             const hash = sys.createHash(data);
             const mtimeBefore = sys.getModifiedTime(fileName);
 
-            if (mtimeBefore && fileName in outputFingerprints) {
-                const fingerprint = outputFingerprints[fileName];
-
+            if (mtimeBefore) {
+                const fingerprint = outputFingerprints.get(fileName);
                 // If output has not been changed, and the file has no external modification
-                if (fingerprint.byteOrderMark === writeByteOrderMark &&
+                if (fingerprint &&
+                    fingerprint.byteOrderMark === writeByteOrderMark &&
                     fingerprint.hash === hash &&
                     fingerprint.mtime.getTime() === mtimeBefore.getTime()) {
                     return;
@@ -154,11 +154,11 @@ namespace ts {
 
             const mtimeAfter = sys.getModifiedTime(fileName);
 
-            outputFingerprints[fileName] = {
+            outputFingerprints.set(fileName, {
                 hash,
                 byteOrderMark: writeByteOrderMark,
                 mtime: mtimeAfter
-            };
+            });
         }
 
         function writeFile(fileName: string, data: string, writeByteOrderMark: boolean, onError?: (message: string) => void) {
@@ -278,9 +278,13 @@ namespace ts {
         const resolutions: T[] = [];
         const cache = createMap<T>();
         for (const name of names) {
-            const result = name in cache
-                ? cache[name]
-                : cache[name] = loader(name, containingFile);
+            let result: T;
+            if (cache.has(name)) {
+                result = cache.get(name);
+            }
+            else {
+                cache.set(name, result = loader(name, containingFile));
+            }
             resolutions.push(result);
         }
         return resolutions;
@@ -460,7 +464,7 @@ namespace ts {
                 classifiableNames = createMap<string>();
 
                 for (const sourceFile of files) {
-                    copyProperties(sourceFile.classifiableNames, classifiableNames);
+                    copyEntries(sourceFile.classifiableNames, classifiableNames);
                 }
             }
 
@@ -735,7 +739,7 @@ namespace ts {
         }
 
         function isSourceFileFromExternalLibrary(file: SourceFile): boolean {
-            return sourceFilesFoundSearchingNodeModules[file.path];
+            return sourceFilesFoundSearchingNodeModules.get(file.path);
         }
 
         function getDiagnosticsProducingTypeChecker() {
@@ -1298,20 +1302,20 @@ namespace ts {
 
                 // If the file was previously found via a node_modules search, but is now being processed as a root file,
                 // then everything it sucks in may also be marked incorrectly, and needs to be checked again.
-                if (file && sourceFilesFoundSearchingNodeModules[file.path] && currentNodeModulesDepth == 0) {
-                    sourceFilesFoundSearchingNodeModules[file.path] = false;
+                if (file && sourceFilesFoundSearchingNodeModules.get(file.path) && currentNodeModulesDepth == 0) {
+                    sourceFilesFoundSearchingNodeModules.set(file.path, false);
                     if (!options.noResolve) {
                         processReferencedFiles(file, isDefaultLib);
                         processTypeReferenceDirectives(file);
                     }
 
-                    modulesWithElidedImports[file.path] = false;
+                    modulesWithElidedImports.set(file.path, false);
                     processImportedModules(file);
                 }
                 // See if we need to reprocess the imports due to prior skipped imports
-                else if (file && modulesWithElidedImports[file.path]) {
+                else if (file && modulesWithElidedImports.get(file.path)) {
                     if (currentNodeModulesDepth < maxNodeModuleJsDepth) {
-                        modulesWithElidedImports[file.path] = false;
+                        modulesWithElidedImports.set(file.path, false);
                         processImportedModules(file);
                     }
                 }
@@ -1332,7 +1336,7 @@ namespace ts {
 
             filesByName.set(path, file);
             if (file) {
-                sourceFilesFoundSearchingNodeModules[path] = (currentNodeModulesDepth > 0);
+                sourceFilesFoundSearchingNodeModules.set(path, currentNodeModulesDepth > 0);
                 file.path = path;
 
                 if (host.useCaseSensitiveFileNames()) {
@@ -1393,7 +1397,7 @@ namespace ts {
             refFile?: SourceFile, refPos?: number, refEnd?: number): void {
 
             // If we already found this library as a primary reference - nothing to do
-            const previousResolution = resolvedTypeReferenceDirectives[typeReferenceDirective];
+            const previousResolution = resolvedTypeReferenceDirectives.get(typeReferenceDirective);
             if (previousResolution && previousResolution.primary) {
                 return;
             }
@@ -1433,7 +1437,7 @@ namespace ts {
             }
 
             if (saveResolution) {
-                resolvedTypeReferenceDirectives[typeReferenceDirective] = resolvedTypeReferenceDirective;
+                resolvedTypeReferenceDirectives.set(typeReferenceDirective, resolvedTypeReferenceDirective);
             }
         }
 
@@ -1486,7 +1490,7 @@ namespace ts {
                     const shouldAddFile = resolvedFileName && !getResolutionDiagnostic(options, resolution) && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
-                        modulesWithElidedImports[file.path] = true;
+                        modulesWithElidedImports.set(file.path, true);
                     }
                     else if (shouldAddFile) {
                         const path = toPath(resolvedFileName, currentDirectory, getCanonicalFileName);

src/compiler/scanner.ts

@@ -56,7 +56,7 @@ namespace ts {
         tryScan<T>(callback: () => T): T;
     }
 
-    const textToToken = createMap({
+    const textToToken = createMapFromTemplate({
         "abstract": SyntaxKind.AbstractKeyword,
         "any": SyntaxKind.AnyKeyword,
         "as": SyntaxKind.AsKeyword,
@@ -276,9 +276,9 @@ namespace ts {
 
     function makeReverseMap(source: Map<number>): string[] {
         const result: string[] = [];
-        for (const name in source) {
-            result[source[name]] = name;
-        }
+        source.forEach((value, name) => {
+            result[value] = name;
+        });
         return result;
     }
 
@@ -290,7 +290,7 @@ namespace ts {
 
     /* @internal */
     export function stringToToken(s: string): SyntaxKind {
-        return textToToken[s];
+        return textToToken.get(s);
     }
 
     /* @internal */
@@ -364,8 +364,6 @@ namespace ts {
         return computeLineAndCharacterOfPosition(getLineStarts(sourceFile), position);
     }
 
-    const hasOwnProperty = Object.prototype.hasOwnProperty;
-
     export function isWhiteSpace(ch: number): boolean {
         return isWhiteSpaceSingleLine(ch) || isLineBreak(ch);
     }
@@ -734,11 +732,11 @@ namespace ts {
         return comments;
     }
 
-    export function getLeadingCommentRanges(text: string, pos: number): CommentRange[] {
+    export function getLeadingCommentRanges(text: string, pos: number): CommentRange[] | undefined {
         return reduceEachLeadingCommentRange(text, pos, appendCommentRange, undefined, undefined);
     }
 
-    export function getTrailingCommentRanges(text: string, pos: number): CommentRange[] {
+    export function getTrailingCommentRanges(text: string, pos: number): CommentRange[] | undefined {
         return reduceEachTrailingCommentRange(text, pos, appendCommentRange, undefined, undefined);
     }
 
@@ -1184,8 +1182,11 @@ namespace ts {
             const len = tokenValue.length;
             if (len >= 2 && len <= 11) {
                 const ch = tokenValue.charCodeAt(0);
-                if (ch >= CharacterCodes.a && ch <= CharacterCodes.z && hasOwnProperty.call(textToToken, tokenValue)) {
-                    return token = textToToken[tokenValue];
+                if (ch >= CharacterCodes.a && ch <= CharacterCodes.z) {
+                    token = textToToken.get(tokenValue);
+                    if (token !== undefined) {
+                        return token;
+                    }
                 }
             }
             return token = SyntaxKind.Identifier;

src/compiler/sys.ts

@@ -1,4 +1,4 @@
-/// <reference path="core.ts"/>
+/// <reference path="core.ts"/>
 
 declare function setTimeout(handler: (...args: any[]) => void, timeout: number): any;
 declare function clearTimeout(handle: any): void;
@@ -246,23 +246,23 @@ namespace ts {
             function createWatchedFileSet() {
                 const dirWatchers = createMap<DirectoryWatcher>();
                 // One file can have multiple watchers
-                const fileWatcherCallbacks = createMap<FileWatcherCallback[]>();
+                const fileWatcherCallbacks = createMultiMap<FileWatcherCallback>();
                 return { addFile, removeFile };
 
                 function reduceDirWatcherRefCountForFile(fileName: string) {
                     const dirName = getDirectoryPath(fileName);
-                    const watcher = dirWatchers[dirName];
+                    const watcher = dirWatchers.get(dirName);
                     if (watcher) {
                         watcher.referenceCount -= 1;
                         if (watcher.referenceCount <= 0) {
                             watcher.close();
-                            delete dirWatchers[dirName];
+                            dirWatchers.delete(dirName);
                         }
                     }
                 }
 
                 function addDirWatcher(dirPath: string): void {
-                    let watcher = dirWatchers[dirPath];
+                    let watcher = dirWatchers.get(dirPath);
                     if (watcher) {
                         watcher.referenceCount += 1;
                         return;
@@ -273,12 +273,12 @@ namespace ts {
                         (eventName: string, relativeFileName: string) => fileEventHandler(eventName, relativeFileName, dirPath)
                     );
                     watcher.referenceCount = 1;
-                    dirWatchers[dirPath] = watcher;
+                    dirWatchers.set(dirPath, watcher);
                     return;
                 }
 
                 function addFileWatcherCallback(filePath: string, callback: FileWatcherCallback): void {
-                    multiMapAdd(fileWatcherCallbacks, filePath, callback);
+                    fileWatcherCallbacks.add(filePath, callback);
                 }
 
                 function addFile(fileName: string, callback: FileWatcherCallback): WatchedFile {
@@ -294,7 +294,7 @@ namespace ts {
                 }
 
                 function removeFileWatcherCallback(filePath: string, callback: FileWatcherCallback) {
-                    multiMapRemove(fileWatcherCallbacks, filePath, callback);
+                    fileWatcherCallbacks.remove(filePath, callback);
                 }
 
                 function fileEventHandler(eventName: string, relativeFileName: string, baseDirPath: string) {
@@ -303,9 +303,12 @@ namespace ts {
                         ? undefined
                         : ts.getNormalizedAbsolutePath(relativeFileName, baseDirPath);
                     // Some applications save a working file via rename operations
-                    if ((eventName === "change" || eventName === "rename") && fileWatcherCallbacks[fileName]) {
-                        for (const fileCallback of fileWatcherCallbacks[fileName]) {
-                            fileCallback(fileName);
+                    if ((eventName === "change" || eventName === "rename")) {
+                        const callbacks = fileWatcherCallbacks.get(fileName);
+                        if (callbacks) {
+                            for (const fileCallback of callbacks) {
+                                fileCallback(fileName);
+                            }
                         }
                     }
                 }

src/compiler/transformer.ts

@@ -1,4 +1,4 @@
-/// <reference path="visitor.ts" />
+/// <reference path="visitor.ts" />
 /// <reference path="transformers/ts.ts" />
 /// <reference path="transformers/jsx.ts" />
 /// <reference path="transformers/esnext.ts" />
@@ -13,14 +13,16 @@
 
 /* @internal */
 namespace ts {
-    const moduleTransformerMap = createMap<Transformer>({
-        [ModuleKind.ES2015]: transformES2015Module,
-        [ModuleKind.System]: transformSystemModule,
-        [ModuleKind.AMD]: transformModule,
-        [ModuleKind.CommonJS]: transformModule,
-        [ModuleKind.UMD]: transformModule,
-        [ModuleKind.None]: transformModule,
-    });
+    function getModuleTransformer(moduleKind: ModuleKind): Transformer {
+        switch (moduleKind) {
+            case ModuleKind.ES2015:
+                return transformES2015Module;
+            case ModuleKind.System:
+                return transformSystemModule;
+            default:
+                return transformModule;
+        }
+    }
 
     const enum SyntaxKindFeatureFlags {
         Substitution = 1 << 0,
@@ -56,7 +58,7 @@ namespace ts {
             transformers.push(transformGenerators);
         }
 
-        transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
+        transformers.push(getModuleTransformer(moduleKind));
 
         // The ES5 transformer is last so that it can substitute expressions like `exports.default`
         // for ES3.

src/compiler/transformers/es2015.ts

@@ -599,7 +599,7 @@ namespace ts {
                 //   - break/continue is non-labeled and located in non-converted loop/switch statement
                 const jump = node.kind === SyntaxKind.BreakStatement ? Jump.Break : Jump.Continue;
                 const canUseBreakOrContinue =
-                    (node.label && convertedLoopState.labels && convertedLoopState.labels[node.label.text]) ||
+                    (node.label && convertedLoopState.labels && convertedLoopState.labels.get(node.label.text)) ||
                     (!node.label && (convertedLoopState.allowedNonLabeledJumps & jump));
 
                 if (!canUseBreakOrContinue) {
@@ -2135,11 +2135,11 @@ namespace ts {
         }
 
         function recordLabel(node: LabeledStatement) {
-            convertedLoopState.labels[node.label.text] = node.label.text;
+            convertedLoopState.labels.set(node.label.text, node.label.text);
         }
 
         function resetLabel(node: LabeledStatement) {
-            convertedLoopState.labels[node.label.text] = undefined;
+            convertedLoopState.labels.set(node.label.text, undefined);
         }
 
         function visitLabeledStatement(node: LabeledStatement): VisitResult<Statement> {
@@ -2798,13 +2798,13 @@ namespace ts {
                 if (!state.labeledNonLocalBreaks) {
                     state.labeledNonLocalBreaks = createMap<string>();
                 }
-                state.labeledNonLocalBreaks[labelText] = labelMarker;
+                state.labeledNonLocalBreaks.set(labelText, labelMarker);
             }
             else {
                 if (!state.labeledNonLocalContinues) {
                     state.labeledNonLocalContinues = createMap<string>();
                 }
-                state.labeledNonLocalContinues[labelText] = labelMarker;
+                state.labeledNonLocalContinues.set(labelText, labelMarker);
             }
         }
 
@@ -2812,13 +2812,12 @@ namespace ts {
             if (!table) {
                 return;
             }
-            for (const labelText in table) {
-                const labelMarker = table[labelText];
+            table.forEach((labelMarker, labelText) => {
                 const statements: Statement[] = [];
                 // if there are no outer converted loop or outer label in question is located inside outer converted loop
                 // then emit labeled break\continue
                 // otherwise propagate pair 'label -> marker' to outer converted loop and emit 'return labelMarker' so outer loop can later decide what to do
-                if (!outerLoop || (outerLoop.labels && outerLoop.labels[labelText])) {
+                if (!outerLoop || (outerLoop.labels && outerLoop.labels.get(labelText))) {
                     const label = createIdentifier(labelText);
                     statements.push(isBreak ? createBreak(label) : createContinue(label));
                 }
@@ -2827,7 +2826,7 @@ namespace ts {
                     statements.push(createReturn(loopResultName));
                 }
                 caseClauses.push(createCaseClause(createLiteral(labelMarker), statements));
-            }
+            });
         }
 
         function processLoopVariableDeclaration(decl: VariableDeclaration | BindingElement, loopParameters: ParameterDeclaration[], loopOutParameters: LoopOutParameter[]) {

src/compiler/transformers/generators.ts

@@ -1,4 +1,4 @@
-/// <reference path="../factory.ts" />
+/// <reference path="../factory.ts" />
 /// <reference path="../visitor.ts" />
 
 // Transforms generator functions into a compatible ES5 representation with similar runtime
@@ -217,13 +217,15 @@ namespace ts {
         Endfinally = 7,
     }
 
-    const instructionNames = createMap<string>({
-        [Instruction.Return]: "return",
-        [Instruction.Break]: "break",
-        [Instruction.Yield]: "yield",
-        [Instruction.YieldStar]: "yield*",
-        [Instruction.Endfinally]: "endfinally",
-    });
+    function getInstructionName(instruction: Instruction): string {
+        switch (instruction) {
+            case Instruction.Return: return "return";
+            case Instruction.Break: return "break";
+            case Instruction.Yield: return "yield";
+            case Instruction.YieldStar: return "yield*";
+            case Instruction.Endfinally: return "endfinally";
+        }
+    }
 
     export function transformGenerators(context: TransformationContext) {
         const {
@@ -241,7 +243,7 @@ namespace ts {
 
         let currentSourceFile: SourceFile;
         let renamedCatchVariables: Map<boolean>;
-        let renamedCatchVariableDeclarations: Map<Identifier>;
+        let renamedCatchVariableDeclarations: Identifier[];
 
         let inGeneratorFunctionBody: boolean;
         let inStatementContainingYield: boolean;
@@ -1923,12 +1925,12 @@ namespace ts {
         }
 
         function substituteExpressionIdentifier(node: Identifier) {
-            if (renamedCatchVariables && hasProperty(renamedCatchVariables, node.text)) {
+            if (renamedCatchVariables && renamedCatchVariables.has(node.text)) {
                 const original = getOriginalNode(node);
                 if (isIdentifier(original) && original.parent) {
                     const declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        const name = getProperty(renamedCatchVariableDeclarations, String(getOriginalNodeId(declaration)));
+                        const name = renamedCatchVariableDeclarations[getOriginalNodeId(declaration)];
                         if (name) {
                             const clone = getMutableClone(name);
                             setSourceMapRange(clone, node);
@@ -2094,11 +2096,11 @@ namespace ts {
 
             if (!renamedCatchVariables) {
                 renamedCatchVariables = createMap<boolean>();
-                renamedCatchVariableDeclarations = createMap<Identifier>();
+                renamedCatchVariableDeclarations = [];
                 context.enableSubstitution(SyntaxKind.Identifier);
             }
 
-            renamedCatchVariables[text] = true;
+            renamedCatchVariables.set(text, true);
             renamedCatchVariableDeclarations[getOriginalNodeId(variable)] = name;
 
             const exception = <ExceptionBlock>peekBlock();
@@ -2403,7 +2405,7 @@ namespace ts {
          */
         function createInstruction(instruction: Instruction): NumericLiteral {
             const literal = createLiteral(instruction);
-            literal.trailingComment = instructionNames[instruction];
+            literal.trailingComment = getInstructionName(instruction);
             return literal;
         }
 

src/compiler/transformers/jsx.ts

@@ -238,7 +238,7 @@ namespace ts {
                     return String.fromCharCode(parseInt(hex, 16));
                 }
                 else {
-                    const ch = entities[word];
+                    const ch = entities.get(word);
                     // If this is not a valid entity, then just use `match` (replace it with itself, i.e. don't replace)
                     return ch ? String.fromCharCode(ch) : match;
                 }
@@ -286,7 +286,7 @@ namespace ts {
         }
     }
 
-    const entities = createMap<number>({
+    const entities = createMapFromTemplate<number>({
         "quot": 0x0022,
         "amp": 0x0026,
         "apos": 0x0027,

src/compiler/transformers/module/module.ts

@@ -1,4 +1,4 @@
-/// <reference path="../../factory.ts" />
+/// <reference path="../../factory.ts" />
 /// <reference path="../../visitor.ts" />
 
 /*@internal*/
@@ -10,12 +10,13 @@ namespace ts {
             importAliasNames: ParameterDeclaration[];
         }
 
-        const transformModuleDelegates = createMap<(node: SourceFile) => SourceFile>({
-            [ModuleKind.None]: transformCommonJSModule,
-            [ModuleKind.CommonJS]: transformCommonJSModule,
-            [ModuleKind.AMD]: transformAMDModule,
-            [ModuleKind.UMD]: transformUMDModule,
-        });
+        function getTransformModuleDelegate(moduleKind: ModuleKind): (node: SourceFile) => SourceFile {
+            switch (moduleKind) {
+                case ModuleKind.AMD: return transformAMDModule;
+                case ModuleKind.UMD: return transformUMDModule;
+                default: return transformCommonJSModule;
+            }
+        }
 
         const {
             startLexicalEnvironment,
@@ -38,12 +39,12 @@ namespace ts {
         context.enableSubstitution(SyntaxKind.ShorthandPropertyAssignment); // Substitutes shorthand property assignments for imported/exported symbols.
         context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
 
-        const moduleInfoMap = createMap<ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
-        const deferredExports = createMap<Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
+        const moduleInfoMap: ExternalModuleInfo[] = []; // The ExternalModuleInfo for each file.
+        const deferredExports: Statement[][] = []; // Exports to defer until an EndOfDeclarationMarker is found.
 
         let currentSourceFile: SourceFile; // The current file.
         let currentModuleInfo: ExternalModuleInfo; // The ExternalModuleInfo for the current file.
-        let noSubstitution: Map<boolean>; // Set of nodes for which substitution rules should be ignored.
+        let noSubstitution: boolean[]; // Set of nodes for which substitution rules should be ignored.
 
         return transformSourceFile;
 
@@ -60,10 +61,11 @@ namespace ts {
             }
 
             currentSourceFile = node;
-            currentModuleInfo = moduleInfoMap[getOriginalNodeId(node)] = collectExternalModuleInfo(node, resolver, compilerOptions);
+            currentModuleInfo = collectExternalModuleInfo(node, resolver, compilerOptions);
+            moduleInfoMap[getOriginalNodeId(node)] = currentModuleInfo;
 
             // Perform the transformation.
-            const transformModule = transformModuleDelegates[moduleKind] || transformModuleDelegates[ModuleKind.None];
+            const transformModule = getTransformModuleDelegate(moduleKind);
             const updated = transformModule(node);
 
             currentSourceFile = undefined;
@@ -1083,7 +1085,7 @@ namespace ts {
          */
         function appendExportsOfDeclaration(statements: Statement[] | undefined, decl: Declaration): Statement[] | undefined {
             const name = getDeclarationName(decl);
-            const exportSpecifiers = currentModuleInfo.exportSpecifiers[name.text];
+            const exportSpecifiers = currentModuleInfo.exportSpecifiers.get(name.text);
             if (exportSpecifiers) {
                 for (const exportSpecifier of exportSpecifiers) {
                     statements = appendExportStatement(statements, exportSpecifier.name, name, /*location*/ exportSpecifier.name);
@@ -1107,7 +1109,7 @@ namespace ts {
         function appendExportStatement(statements: Statement[] | undefined, exportName: Identifier, expression: Expression, location?: TextRange, allowComments?: boolean): Statement[] | undefined {
             if (exportName.text === "default") {
                 const sourceFile = getOriginalNode(currentSourceFile, isSourceFile);
-                if (sourceFile && !sourceFile.symbol.exports["___esModule"]) {
+                if (sourceFile && !sourceFile.symbol.exports.get("___esModule")) {
                     if (languageVersion === ScriptTarget.ES3) {
                         statements = append(statements,
                             createStatement(
@@ -1213,7 +1215,7 @@ namespace ts {
             if (node.kind === SyntaxKind.SourceFile) {
                 currentSourceFile = <SourceFile>node;
                 currentModuleInfo = moduleInfoMap[getOriginalNodeId(currentSourceFile)];
-                noSubstitution = createMap<boolean>();
+                noSubstitution = [];
 
                 previousOnEmitNode(emitContext, node, emitCallback);
 

src/compiler/transformers/module/system.ts

@@ -1,4 +1,4 @@
-/// <reference path="../../factory.ts" />
+/// <reference path="../../factory.ts" />
 /// <reference path="../../visitor.ts" />
 
 /*@internal*/
@@ -28,10 +28,10 @@ namespace ts {
         context.enableSubstitution(SyntaxKind.PostfixUnaryExpression); // Substitutes updates to exported symbols.
         context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
 
-        const moduleInfoMap = createMap<ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
-        const deferredExports = createMap<Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
-        const exportFunctionsMap = createMap<Identifier>(); // The export function associated with a source file.
-        const noSubstitutionMap = createMap<Map<boolean>>(); // Set of nodes for which substitution rules should be ignored for each file.
+        const moduleInfoMap: ExternalModuleInfo[] = []; // The ExternalModuleInfo for each file.
+        const deferredExports: Statement[][] = []; // Exports to defer until an EndOfDeclarationMarker is found.
+        const exportFunctionsMap: Identifier[] = []; // The export function associated with a source file.
+        const noSubstitutionMap: boolean[][] = []; // Set of nodes for which substitution rules should be ignored for each file.
 
         let currentSourceFile: SourceFile; // The current file.
         let moduleInfo: ExternalModuleInfo; // ExternalModuleInfo for the current file.
@@ -39,7 +39,7 @@ namespace ts {
         let contextObject: Identifier; // The context object for the current file.
         let hoistedStatements: Statement[];
         let enclosingBlockScopedContainer: Node;
-        let noSubstitution: Map<boolean>; // Set of nodes for which substitution rules should be ignored.
+        let noSubstitution: boolean[]; // Set of nodes for which substitution rules should be ignored.
 
         return transformSourceFile;
 
@@ -77,7 +77,8 @@ namespace ts {
 
             // Make sure that the name of the 'exports' function does not conflict with
             // existing identifiers.
-            exportFunction = exportFunctionsMap[id] = createUniqueName("exports");
+            exportFunction = createUniqueName("exports");
+            exportFunctionsMap[id] = exportFunction;
             contextObject = createUniqueName("context");
 
             // Add the body of the module.
@@ -148,13 +149,13 @@ namespace ts {
                 const externalImport = externalImports[i];
                 const externalModuleName = getExternalModuleNameLiteral(externalImport, currentSourceFile, host, resolver, compilerOptions);
                 const text = externalModuleName.text;
-                if (hasProperty(groupIndices, text)) {
+                const groupIndex = groupIndices.get(text);
+                if (groupIndex !== undefined) {
                     // deduplicate/group entries in dependency list by the dependency name
-                    const groupIndex = groupIndices[text];
                     dependencyGroups[groupIndex].externalImports.push(externalImport);
                 }
                 else {
-                    groupIndices[text] = dependencyGroups.length;
+                    groupIndices.set(text, dependencyGroups.length);
                     dependencyGroups.push({
                         name: externalModuleName,
                         externalImports: [externalImport]
@@ -306,7 +307,7 @@ namespace ts {
             // this set is used to filter names brought by star expors.
 
             // local names set should only be added if we have anything exported
-            if (!moduleInfo.exportedNames && isEmpty(moduleInfo.exportSpecifiers)) {
+            if (!moduleInfo.exportedNames && moduleInfo.exportSpecifiers.size === 0) {
                 // no exported declarations (export var ...) or export specifiers (export {x})
                 // check if we have any non star export declarations.
                 let hasExportDeclarationWithExportClause = false;
@@ -1081,7 +1082,7 @@ namespace ts {
             }
 
             const name = getDeclarationName(decl);
-            const exportSpecifiers = moduleInfo.exportSpecifiers[name.text];
+            const exportSpecifiers = moduleInfo.exportSpecifiers.get(name.text);
             if (exportSpecifiers) {
                 for (const exportSpecifier of exportSpecifiers) {
                     if (exportSpecifier.name.text !== excludeName) {
@@ -1770,7 +1771,7 @@ namespace ts {
          * @param node The node which should not be substituted.
          */
         function preventSubstitution<T extends Node>(node: T): T {
-            if (noSubstitution === undefined) noSubstitution = createMap<boolean>();
+            if (noSubstitution === undefined) noSubstitution = [];
             noSubstitution[getNodeId(node)] = true;
             return node;
         }

src/compiler/transformers/ts.ts

@@ -1,4 +1,4 @@
-/// <reference path="../factory.ts" />
+/// <reference path="../factory.ts" />
 /// <reference path="../visitor.ts" />
 /// <reference path="./destructuring.ts" />
 
@@ -60,7 +60,7 @@ namespace ts {
          * A map that keeps track of aliases created for classes with decorators to avoid issues
          * with the double-binding behavior of classes.
          */
-        let classAliases: Map<Identifier>;
+        let classAliases: Identifier[];
 
         /**
          * Keeps track of whether  we are within any containing namespaces when performing
@@ -2538,8 +2538,8 @@ namespace ts {
                     currentScopeFirstDeclarationsOfName = createMap<Node>();
                 }
 
-                if (!(name in currentScopeFirstDeclarationsOfName)) {
-                    currentScopeFirstDeclarationsOfName[name] = node;
+                if (!currentScopeFirstDeclarationsOfName.has(name)) {
+                    currentScopeFirstDeclarationsOfName.set(name, node);
                 }
             }
         }
@@ -2552,7 +2552,7 @@ namespace ts {
             if (currentScopeFirstDeclarationsOfName) {
                 const name = node.symbol && node.symbol.name;
                 if (name) {
-                    return currentScopeFirstDeclarationsOfName[name] === node;
+                    return currentScopeFirstDeclarationsOfName.get(name) === node;
                 }
             }
 
@@ -3125,7 +3125,7 @@ namespace ts {
                 context.enableSubstitution(SyntaxKind.Identifier);
 
                 // Keep track of class aliases.
-                classAliases = createMap<Identifier>();
+                classAliases = [];
             }
         }
 

src/compiler/tsc.ts

@@ -1,4 +1,4 @@
-/// <reference path="program.ts"/>
+/// <reference path="program.ts"/>
 /// <reference path="commandLineParser.ts"/>
 
 namespace ts {
@@ -67,11 +67,13 @@ namespace ts {
     const gutterSeparator = " ";
     const resetEscapeSequence = "\u001b[0m";
     const ellipsis = "...";
-    const categoryFormatMap = createMap<string>({
-        [DiagnosticCategory.Warning]: yellowForegroundEscapeSequence,
-        [DiagnosticCategory.Error]: redForegroundEscapeSequence,
-        [DiagnosticCategory.Message]: blueForegroundEscapeSequence,
-    });
+    function getCategoryFormat(category: DiagnosticCategory): string {
+        switch (category) {
+            case DiagnosticCategory.Warning: return yellowForegroundEscapeSequence;
+            case DiagnosticCategory.Error: return redForegroundEscapeSequence;
+            case DiagnosticCategory.Message: return blueForegroundEscapeSequence;
+        }
+    }
 
     function formatAndReset(text: string, formatStyle: string) {
         return formatStyle + text + resetEscapeSequence;
@@ -139,7 +141,7 @@ namespace ts {
             output += `${ relativeFileName }(${ firstLine + 1 },${ firstLineChar + 1 }): `;
         }
 
-        const categoryColor = categoryFormatMap[diagnostic.category];
+        const categoryColor = getCategoryFormat(diagnostic.category);
         const category = DiagnosticCategory[diagnostic.category].toLowerCase();
         output += `${ formatAndReset(category, categoryColor) } TS${ diagnostic.code }: ${ flattenDiagnosticMessageText(diagnostic.messageText, sys.newLine) }`;
         output += sys.newLine + sys.newLine;
@@ -155,7 +157,7 @@ namespace ts {
             output += `${ diagnostic.file.fileName }(${ loc.line + 1 },${ loc.character + 1 }): `;
         }
 
-        output += `${ flattenDiagnosticMessageText(diagnostic.messageText, sys.newLine) }${ sys.newLine }`;
+        output += `${ flattenDiagnosticMessageText(diagnostic.messageText, sys.newLine) }${ sys.newLine + sys.newLine + sys.newLine }`;
 
         sys.write(output);
     }
@@ -378,9 +380,11 @@ namespace ts {
         }
 
         function cachedFileExists(fileName: string): boolean {
-            return fileName in cachedExistingFiles
-                ? cachedExistingFiles[fileName]
-                : cachedExistingFiles[fileName] = hostFileExists(fileName);
+            let fileExists = cachedExistingFiles.get(fileName);
+            if (fileExists === undefined) {
+                cachedExistingFiles.set(fileName, fileExists = hostFileExists(fileName));
+            }
+            return fileExists;
         }
 
         function getSourceFile(fileName: string, languageVersion: ScriptTarget, onError?: (message: string) => void) {
@@ -674,13 +678,9 @@ namespace ts {
 
             if (option.name === "lib") {
                 description = getDiagnosticText(option.description);
-                const options: string[] = [];
                 const element = (<CommandLineOptionOfListType>option).element;
                 const typeMap = <Map<number | string>>element.type;
-                for (const key in typeMap) {
-                    options.push(`'${key}'`);
-                }
-                optionsDescriptionMap[description] = options;
+                optionsDescriptionMap.set(description, arrayFrom(typeMap.keys()).map(key => `'${key}'`));
             }
             else {
                 description = getDiagnosticText(option.description);
@@ -702,7 +702,7 @@ namespace ts {
         for (let i = 0; i < usageColumn.length; i++) {
             const usage = usageColumn[i];
             const description = descriptionColumn[i];
-            const kindsList = optionsDescriptionMap[description];
+            const kindsList = optionsDescriptionMap.get(description);
             output.push(usage + makePadding(marginLength - usage.length + 2) + description + sys.newLine);
 
             if (kindsList) {

src/compiler/tsconfig.json

@@ -3,8 +3,7 @@
     "compilerOptions": {
         "removeComments": true,
         "outFile": "../../built/local/tsc.js",
-        "declaration": true,
-        "types": [ ]
+        "declaration": true
     },
     "files": [
         "core.ts",

src/compiler/types.ts

@@ -1,11 +1,30 @@
-namespace ts {
-
+namespace ts {
+    /**
+     * Type of objects whose values are all of the same type.
+     * The `in` and `for-in` operators can *not* be safely used,
+     * since `Object.prototype` may be modified by outside code.
+     */
     export interface MapLike<T> {
         [index: string]: T;
     }
 
-    export interface Map<T> extends MapLike<T> {
-        __mapBrand: any;
+    /** ES6 Map interface. */
+    export interface Map<T> {
+        get(key: string): T;
+        has(key: string): boolean;
+        set(key: string, value: T): this;
+        delete(key: string): boolean;
+        clear(): void;
+        forEach(action: (value: T, key: string) => void): void;
+        readonly size: number;
+        keys(): Iterator<string>;
+        values(): Iterator<T>;
+        entries(): Iterator<[string, T]>;
+    }
+
+    /** ES6 Iterator type. */
+    export interface Iterator<T> {
+        next(): { value: T, done: false } | { value: never, done: true };
     }
 
     // branded string type used to store absolute, normalized and canonicalized paths
@@ -2341,6 +2360,11 @@ namespace ts {
         getIndexTypeOfType(type: Type, kind: IndexKind): Type;
         getBaseTypes(type: InterfaceType): ObjectType[];
         getReturnTypeOfSignature(signature: Signature): Type;
+        /**
+         * Gets the type of a parameter at a given position in a signature.
+         * Returns `any` if the index is not valid.
+         */
+        /* @internal */ getParameterType(signature: Signature, parameterIndex: number): Type;
         getNonNullableType(type: Type): Type;
 
         getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[];
@@ -2370,6 +2394,8 @@ namespace ts {
         isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName, propertyName: string): boolean;
         getAliasedSymbol(symbol: Symbol): Symbol;
         getExportsOfModule(moduleSymbol: Symbol): Symbol[];
+        /** Unlike `getExportsOfModule`, this includes properties of an `export =` value. */
+        /* @internal */ getExportsAndPropertiesOfModule(moduleSymbol: Symbol): Symbol[];
 
         getJsxElementAttributesType(elementNode: JsxOpeningLikeElement): Type;
         getJsxIntrinsicTagNames(): Symbol[];
@@ -2847,7 +2873,7 @@ namespace ts {
 
     // Enum types (TypeFlags.Enum)
     export interface EnumType extends Type {
-        memberTypes: Map<EnumLiteralType>;
+        memberTypes: EnumLiteralType[];
     }
 
     // Enum types (TypeFlags.EnumLiteral)
@@ -3682,7 +3708,7 @@ namespace ts {
         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
+        tokenSourceMapRanges?: 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

src/compiler/utilities.ts

@@ -1,4 +1,4 @@
-/// <reference path="sys.ts" />
+/// <reference path="sys.ts" />
 
 /* @internal */
 namespace ts {
@@ -70,11 +70,11 @@ namespace ts {
     }
 
     export function hasResolvedModule(sourceFile: SourceFile, moduleNameText: string): boolean {
-        return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules[moduleNameText]);
+        return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules.get(moduleNameText));
     }
 
     export function getResolvedModule(sourceFile: SourceFile, moduleNameText: string): ResolvedModuleFull {
-        return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules[moduleNameText] : undefined;
+        return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules.get(moduleNameText) : undefined;
     }
 
     export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModuleFull): void {
@@ -82,7 +82,7 @@ namespace ts {
             sourceFile.resolvedModules = createMap<ResolvedModuleFull>();
         }
 
-        sourceFile.resolvedModules[moduleNameText] = resolvedModule;
+        sourceFile.resolvedModules.set(moduleNameText, resolvedModule);
     }
 
     export function setResolvedTypeReferenceDirective(sourceFile: SourceFile, typeReferenceDirectiveName: string, resolvedTypeReferenceDirective: ResolvedTypeReferenceDirective): void {
@@ -90,7 +90,7 @@ namespace ts {
             sourceFile.resolvedTypeReferenceDirectiveNames = createMap<ResolvedTypeReferenceDirective>();
         }
 
-        sourceFile.resolvedTypeReferenceDirectiveNames[typeReferenceDirectiveName] = resolvedTypeReferenceDirective;
+        sourceFile.resolvedTypeReferenceDirectiveNames.set(typeReferenceDirectiveName, resolvedTypeReferenceDirective);
     }
 
     /* @internal */
@@ -112,7 +112,7 @@ namespace ts {
         }
         for (let i = 0; i < names.length; i++) {
             const newResolution = newResolutions[i];
-            const oldResolution = oldResolutions && oldResolutions[names[i]];
+            const oldResolution = oldResolutions && oldResolutions.get(names[i]);
             const changed =
                 oldResolution
                     ? !newResolution || !comparer(oldResolution, newResolution)
@@ -2285,22 +2285,16 @@ namespace ts {
         }
 
         function reattachFileDiagnostics(newFile: SourceFile): void {
-            if (!hasProperty(fileDiagnostics, newFile.fileName)) {
-                return;
-            }
-
-            for (const diagnostic of fileDiagnostics[newFile.fileName]) {
-                diagnostic.file = newFile;
-            }
+            forEach(fileDiagnostics.get(newFile.fileName), diagnostic => diagnostic.file = newFile);
         }
 
         function add(diagnostic: Diagnostic): void {
             let diagnostics: Diagnostic[];
             if (diagnostic.file) {
-                diagnostics = fileDiagnostics[diagnostic.file.fileName];
+                diagnostics = fileDiagnostics.get(diagnostic.file.fileName);
                 if (!diagnostics) {
                     diagnostics = [];
-                    fileDiagnostics[diagnostic.file.fileName] = diagnostics;
+                    fileDiagnostics.set(diagnostic.file.fileName, diagnostics);
                 }
             }
             else {
@@ -2320,7 +2314,7 @@ namespace ts {
         function getDiagnostics(fileName?: string): Diagnostic[] {
             sortAndDeduplicate();
             if (fileName) {
-                return fileDiagnostics[fileName] || [];
+                return fileDiagnostics.get(fileName) || [];
             }
 
             const allDiagnostics: Diagnostic[] = [];
@@ -2330,9 +2324,9 @@ namespace ts {
 
             forEach(nonFileDiagnostics, pushDiagnostic);
 
-            for (const key in fileDiagnostics) {
-                forEach(fileDiagnostics[key], pushDiagnostic);
-            }
+            fileDiagnostics.forEach(diagnostics => {
+                forEach(diagnostics, pushDiagnostic);
+            });
 
             return sortAndDeduplicateDiagnostics(allDiagnostics);
         }
@@ -2345,9 +2339,9 @@ namespace ts {
             diagnosticsModified = false;
             nonFileDiagnostics = sortAndDeduplicateDiagnostics(nonFileDiagnostics);
 
-            for (const key in fileDiagnostics) {
-                fileDiagnostics[key] = sortAndDeduplicateDiagnostics(fileDiagnostics[key]);
-            }
+            fileDiagnostics.forEach((diagnostics, key) => {
+                fileDiagnostics.set(key, sortAndDeduplicateDiagnostics(diagnostics));
+            });
         }
     }
 
@@ -2357,7 +2351,7 @@ namespace ts {
     // the map below must be updated. Note that this regexp *does not* include the 'delete' character.
     // There is no reason for this other than that JSON.stringify does not handle it either.
     const escapedCharsRegExp = /[\\\"\u0000-\u001f\t\v\f\b\r\n\u2028\u2029\u0085]/g;
-    const escapedCharsMap = createMap({
+    const escapedCharsMap = createMapFromTemplate({
         "\0": "\\0",
         "\t": "\\t",
         "\v": "\\v",
@@ -2383,7 +2377,7 @@ namespace ts {
     }
 
     function getReplacement(c: string) {
-        return escapedCharsMap[c] || get16BitUnicodeEscapeSequence(c.charCodeAt(0));
+        return escapedCharsMap.get(c) || get16BitUnicodeEscapeSequence(c.charCodeAt(0));
     }
 
     export function isIntrinsicJsxName(name: string) {
@@ -3383,18 +3377,21 @@ namespace ts {
         return false;
     }
 
-    const syntaxKindCache = createMap<string>();
+    const syntaxKindCache: string[] = [];
 
     export function formatSyntaxKind(kind: SyntaxKind): string {
         const syntaxKindEnum = (<any>ts).SyntaxKind;
         if (syntaxKindEnum) {
-            if (syntaxKindCache[kind]) {
-                return syntaxKindCache[kind];
+            const cached = syntaxKindCache[kind];
+            if (cached !== undefined) {
+                return cached;
             }
 
             for (const name in syntaxKindEnum) {
                 if (syntaxKindEnum[name] === kind) {
-                    return syntaxKindCache[kind] = kind.toString() + " (" + name + ")";
+                    const result = `${kind} (${name})`;
+                    syntaxKindCache[kind] = result;
+                    return result;
                 }
             }
         }

src/compiler/visitor.ts

@@ -1,4 +1,4 @@
-/// <reference path="checker.ts" />
+/// <reference path="checker.ts" />
 /// <reference path="factory.ts" />
 /// <reference path="utilities.ts" />
 
@@ -46,54 +46,56 @@ namespace ts {
      *       supplant the existing `forEachChild` implementation if performance is not
      *       significantly impacted.
      */
-    const nodeEdgeTraversalMap = createMap<NodeTraversalPath>({
-        [SyntaxKind.QualifiedName]: [
-            { name: "left", test: isEntityName },
-            { name: "right", test: isIdentifier }
-        ],
-        [SyntaxKind.Decorator]: [
-            { name: "expression", test: isLeftHandSideExpression }
-        ],
-        [SyntaxKind.TypeAssertionExpression]: [
-            { name: "type", test: isTypeNode },
-            { name: "expression", test: isUnaryExpression }
-        ],
-        [SyntaxKind.AsExpression]: [
-            { name: "expression", test: isExpression },
-            { name: "type", test: isTypeNode }
-        ],
-        [SyntaxKind.NonNullExpression]: [
-            { name: "expression", test: isLeftHandSideExpression }
-        ],
-        [SyntaxKind.EnumDeclaration]: [
-            { name: "decorators", test: isDecorator },
-            { name: "modifiers", test: isModifier },
-            { name: "name", test: isIdentifier },
-            { name: "members", test: isEnumMember }
-        ],
-        [SyntaxKind.ModuleDeclaration]: [
-            { name: "decorators", test: isDecorator },
-            { name: "modifiers", test: isModifier },
-            { name: "name", test: isModuleName },
-            { name: "body", test: isModuleBody }
-        ],
-        [SyntaxKind.ModuleBlock]: [
-            { name: "statements", test: isStatement }
-        ],
-        [SyntaxKind.ImportEqualsDeclaration]: [
-            { name: "decorators", test: isDecorator },
-            { name: "modifiers", test: isModifier },
-            { name: "name", test: isIdentifier },
-            { name: "moduleReference", test: isModuleReference }
-        ],
-        [SyntaxKind.ExternalModuleReference]: [
-            { name: "expression", test: isExpression, optional: true }
-        ],
-        [SyntaxKind.EnumMember]: [
-            { name: "name", test: isPropertyName },
-            { name: "initializer", test: isExpression, optional: true, parenthesize: parenthesizeExpressionForList }
-        ]
-    });
+    function getNodeEdgeTraversal(kind: SyntaxKind): NodeTraversalPath {
+        switch (kind) {
+            case SyntaxKind.QualifiedName: return [
+                { name: "left", test: isEntityName },
+                { name: "right", test: isIdentifier }
+            ];
+            case SyntaxKind.Decorator: return [
+                { name: "expression", test: isLeftHandSideExpression }
+            ];
+            case SyntaxKind.TypeAssertionExpression: return [
+                { name: "type", test: isTypeNode },
+                { name: "expression", test: isUnaryExpression }
+            ];
+            case SyntaxKind.AsExpression: return [
+                { name: "expression", test: isExpression },
+                { name: "type", test: isTypeNode }
+            ];
+            case SyntaxKind.NonNullExpression: return [
+                { name: "expression", test: isLeftHandSideExpression }
+            ];
+            case SyntaxKind.EnumDeclaration: return [
+                { name: "decorators", test: isDecorator },
+                { name: "modifiers", test: isModifier },
+                { name: "name", test: isIdentifier },
+                { name: "members", test: isEnumMember }
+            ];
+            case SyntaxKind.ModuleDeclaration: return [
+                { name: "decorators", test: isDecorator },
+                { name: "modifiers", test: isModifier },
+                { name: "name", test: isModuleName },
+                { name: "body", test: isModuleBody }
+            ];
+            case SyntaxKind.ModuleBlock: return [
+                { name: "statements", test: isStatement }
+            ];
+            case SyntaxKind.ImportEqualsDeclaration: return [
+                { name: "decorators", test: isDecorator },
+                { name: "modifiers", test: isModifier },
+                { name: "name", test: isIdentifier },
+                { name: "moduleReference", test: isModuleReference }
+            ];
+            case SyntaxKind.ExternalModuleReference: return [
+                { name: "expression", test: isExpression, optional: true }
+            ];
+            case SyntaxKind.EnumMember: return [
+                { name: "name", test: isPropertyName },
+                { name: "initializer", test: isExpression, optional: true, parenthesize: parenthesizeExpressionForList }
+            ];
+        }
+    }
 
     function reduceNode<T>(node: Node, f: (memo: T, node: Node) => T, initial: T) {
         return node ? f(initial, node) : initial;
@@ -530,7 +532,7 @@ namespace ts {
                 break;
 
             default:
-                const edgeTraversalPath = nodeEdgeTraversalMap[kind];
+                const edgeTraversalPath = getNodeEdgeTraversal(kind);
                 if (edgeTraversalPath) {
                     for (const edge of edgeTraversalPath) {
                         const value = (<MapLike<any>>node)[edge.name];
@@ -1188,10 +1190,10 @@ namespace ts {
 
             default:
                 let updated: Node & MapLike<any>;
-                const edgeTraversalPath = nodeEdgeTraversalMap[kind];
+                const edgeTraversalPath = getNodeEdgeTraversal(kind);
                 if (edgeTraversalPath) {
                     for (const edge of edgeTraversalPath) {
-                        const value = <Node | NodeArray<Node>>(<Node & Map<any>>node)[edge.name];
+                        const value = <Node | NodeArray<Node>>(<Node & MapLike<any>>node)[edge.name];
                         if (value !== undefined) {
                             const visited = isArray(value)
                                 ? visitNodes(value, visitor, edge.test, 0, value.length, edge.parenthesize, node)