Don’t assume importing some JSON means you want everything imported with .js extensions (#34961)

Author: andrewbranch

src/compiler/moduleSpecifiers.ts

@@ -30,7 +30,7 @@ namespace ts.moduleSpecifiers {
     function getPreferencesForUpdate(compilerOptions: CompilerOptions, oldImportSpecifier: string): Preferences {
         return {
             relativePreference: isExternalModuleNameRelative(oldImportSpecifier) ? RelativePreference.Relative : RelativePreference.NonRelative,
-            ending: hasJSOrJsonFileExtension(oldImportSpecifier) ?
+            ending: hasJSFileExtension(oldImportSpecifier) ?
                 Ending.JsExtension :
                 getEmitModuleResolutionKind(compilerOptions) !== ModuleResolutionKind.NodeJs || endsWith(oldImportSpecifier, "index") ? Ending.Index : Ending.Minimal,
         };
@@ -163,7 +163,7 @@ namespace ts.moduleSpecifiers {
     }
 
     function usesJsExtensionOnImports({ imports }: SourceFile): boolean {
-        return firstDefined(imports, ({ text }) => pathIsRelative(text) ? hasJSOrJsonFileExtension(text) : undefined) || false;
+        return firstDefined(imports, ({ text }) => pathIsRelative(text) ? hasJSFileExtension(text) : undefined) || false;
     }
 
     function numberOfDirectorySeparators(str: string) {

src/compiler/utilities.ts

@@ -8131,10 +8131,6 @@ namespace ts {
         return some(supportedJSExtensions, extension => fileExtensionIs(fileName, extension));
     }
 
-    export function hasJSOrJsonFileExtension(fileName: string): boolean {
-        return supportedJSAndJsonExtensions.some(ext => fileExtensionIs(fileName, ext));
-    }
-
     export function hasTSFileExtension(fileName: string): boolean {
         return some(supportedTSExtensions, extension => fileExtensionIs(fileName, extension));
     }

tests/cases/fourslash/importNameCodeFix_withJson.ts

@@ -0,0 +1,15 @@
+/// <reference path="fourslash.ts" />
+
+// @Filename: /a.ts
+////export const a = 'a';
+
+// @Filename: /b.ts
+////import "./anything.json";
+////
+////a/**/
+
+goTo.file("/b.ts");
+verify.importFixAtPosition([`import "./anything.json";
+import { a } from "./a";
+
+a`]);