From 57a50f4b9d9ef0a48a1639ff179397de1b9f47ed Mon Sep 17 00:00:00 2001
From: Andy <anhans@microsoft.com>
Date: Tue, 6 Feb 2018 10:19:14 -0800
Subject: [PATCH] fixInvalidImportSyntax: Preserve comment (#21684)

---
 .../codefixes/fixInvalidImportSyntax.ts       | 37 +++++++------------
 .../fourslash/codeFixCalledES2015Import11.ts  |  4 +-
 2 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/src/services/codefixes/fixInvalidImportSyntax.ts b/src/services/codefixes/fixInvalidImportSyntax.ts
index f98f1eaea7c..e6f18cf5bd7 100644
--- a/src/services/codefixes/fixInvalidImportSyntax.ts
+++ b/src/services/codefixes/fixInvalidImportSyntax.ts
@@ -26,40 +26,35 @@ namespace ts.codefix {
         const variations: CodeAction[] = [];
 
         // import Bluebird from "bluebird";
-        const replacement = createImportDeclaration(
+        variations.push(createAction(context, sourceFile, node, createImportDeclaration(
             /*decorators*/ undefined,
             /*modifiers*/ undefined,
             createImportClause(namespace.name, /*namedBindings*/ undefined),
             node.moduleSpecifier
-        );
-        const changeTracker = textChanges.ChangeTracker.fromContext(context);
-        changeTracker.replaceNode(sourceFile, node, replacement, { useNonAdjustedEndPosition: true });
-        const changes = changeTracker.getChanges();
-        variations.push({
-            description: formatStringFromArgs(getLocaleSpecificMessage(Diagnostics.Replace_import_with_0), [changes[0].textChanges[0].newText]),
-            changes
-        });
+        )));
 
         if (getEmitModuleKind(opts) === ModuleKind.CommonJS) {
             // import Bluebird = require("bluebird");
-            const replacement = createImportEqualsDeclaration(
+            variations.push(createAction(context, sourceFile, node, createImportEqualsDeclaration(
                 /*decorators*/ undefined,
                 /*modifiers*/ undefined,
                 namespace.name,
                 createExternalModuleReference(node.moduleSpecifier)
-            );
-            const changeTracker = textChanges.ChangeTracker.fromContext(context);
-            changeTracker.replaceNode(sourceFile, node, replacement, { useNonAdjustedEndPosition: true });
-            const changes = changeTracker.getChanges();
-            variations.push({
-                description: formatStringFromArgs(getLocaleSpecificMessage(Diagnostics.Replace_import_with_0), [changes[0].textChanges[0].newText]),
-                changes
-            });
+            )));
         }
 
         return variations;
     }
 
+    function createAction(context: CodeFixContext, sourceFile: SourceFile, node: Node, replacement: Node): CodeAction {
+        // TODO: GH#21246 Should be able to use `replaceNode`, but be sure to preserve comments (see `codeFixCalledES2015Import11.ts`)
+        const changes = textChanges.ChangeTracker.with(context, t => t.replaceRange(sourceFile, { pos: node.getStart(), end: node.end }, replacement));
+        return {
+            description: formatStringFromArgs(getLocaleSpecificMessage(Diagnostics.Replace_import_with_0), [changes[0].textChanges[0].newText]),
+            changes,
+        };
+    }
+
     registerCodeFix({
         errorCodes: [
             Diagnostics.Cannot_invoke_an_expression_whose_type_lacks_a_call_signature_Type_0_has_no_compatible_call_signatures.code,
@@ -85,13 +80,9 @@ namespace ts.codefix {
         if (!isImportCall(relatedImport)) {
             addRange(fixes, getCodeFixesForImportDeclaration(context, relatedImport));
         }
-        const propertyAccess = createPropertyAccess(expr, "default");
-        const changeTracker = textChanges.ChangeTracker.fromContext(context);
-        changeTracker.replaceNode(sourceFile, expr, propertyAccess, {});
-        const changes = changeTracker.getChanges();
         fixes.push({
             description: getLocaleSpecificMessage(Diagnostics.Use_synthetic_default_member),
-            changes
+            changes: textChanges.ChangeTracker.with(context, t => t.replaceNode(sourceFile, expr, createPropertyAccess(expr, "default"), {})),
         });
         return fixes;
     }
diff --git a/tests/cases/fourslash/codeFixCalledES2015Import11.ts b/tests/cases/fourslash/codeFixCalledES2015Import11.ts
index 14b02fa38bc..af0d5c9ed30 100644
--- a/tests/cases/fourslash/codeFixCalledES2015Import11.ts
+++ b/tests/cases/fourslash/codeFixCalledES2015Import11.ts
@@ -6,13 +6,15 @@
 ////export = foo;
 
 // @Filename: index.ts
+////// Comment
 ////import * as foo from "./foo";
 ////[|foo()|];
 
 goTo.file(1);
 verify.codeFix({
     description: `Replace import with 'import foo from "./foo";'.`,
-    newFileContent: `import foo from "./foo";
+    newFileContent: `// Comment
+import foo from "./foo";
 foo();`,
     index: 0,
 });