fix: also respect compilerOptions.moduleResolution for ending preferences

Author: JoshuaKGoldberg

src/compiler/utilities.ts

@@ -9139,7 +9139,9 @@ export function usesExtensionsOnImports({ imports }: SourceFile, hasExtension: (
 
 /** @internal */
 export function getModuleSpecifierEndingPreference(preference: UserPreferences["importModuleSpecifierEnding"], resolutionMode: ResolutionMode, compilerOptions: CompilerOptions, sourceFile: SourceFile): ModuleSpecifierEnding {
-    if (preference === "js" || resolutionMode === ModuleKind.ESNext) {
+    if (preference === "js" ||
+        resolutionMode === ModuleKind.ESNext ||
+        [ModuleResolutionKind.Node16, ModuleResolutionKind.NodeNext].includes(compilerOptions.moduleResolution!)) {
         // Extensions are explicitly requested or required. Now choose between .js and .ts.
         if (!shouldAllowImportingTsExtension(compilerOptions)) {
             return ModuleSpecifierEnding.JsExtension;

tests/cases/fourslash/moveToNewFile_importFileExtensionsNonTypeModule.ts

@@ -0,0 +1,67 @@
+/// <reference path="fourslash.ts"/>
+
+// @Filename: /tsconfig.json
+////{
+////  "compilerOptions": {
+////    "moduleResolution": "Node16",
+////  }
+////}
+
+// @Filename: /src/main.ts
+////[|export function someLibFn(): string {
+////     return main();
+////}|]
+////
+////function main(): string {
+////    return "hello world!";
+////}
+////console.log(someLibFn());
+
+// @Filename: /other.ts
+////import { someLibFn } from "./src/main.js";
+////
+////function someOtherFn(): string {
+////    return someLibFn();
+////}
+
+// @Filename: /act/action.ts
+////import { someLibFn } from "../src/main.js";
+////
+////function doAction(): string {
+////    return someLibFn();
+////}
+
+
+verify.moveToNewFile({
+    newFileContents: {
+      "/src/main.ts": 
+`import { someLibFn } from "./someLibFn.js";
+
+export function main(): string {
+    return "hello world!";
+}
+console.log(someLibFn());`,
+
+      "/src/someLibFn.ts": 
+`import { main } from "./main.js";
+
+export function someLibFn(): string {
+    return main();
+}
+`,
+
+    "/other.ts": 
+`import { someLibFn } from "./src/someLibFn.js";
+
+function someOtherFn(): string {
+    return someLibFn();
+}`,
+
+  "/act/action.ts": 
+`import { someLibFn } from "../src/someLibFn.js";
+
+function doAction(): string {
+    return someLibFn();
+}`,
+    }
+});