Fix helpers emit for .cjs files in ESM module mode

Author: andrewbranch

src/compiler/factory/utilities.ts

@@ -700,9 +700,10 @@ export function createExternalHelpersImportDeclarationIfNeeded(nodeFactory: Node
         const impliedModuleKind = getImpliedNodeFormatForEmitWorker(sourceFile, compilerOptions);
         const helpers = getImportedHelpers(sourceFile);
         if (
-            (moduleKind >= ModuleKind.ES2015 && moduleKind <= ModuleKind.ESNext) ||
-            impliedModuleKind === ModuleKind.ESNext ||
-            impliedModuleKind === undefined && moduleKind === ModuleKind.Preserve
+            impliedModuleKind !== ModuleKind.CommonJS &&
+            ((moduleKind >= ModuleKind.ES2015 && moduleKind <= ModuleKind.ESNext) ||
+                impliedModuleKind === ModuleKind.ESNext ||
+                impliedModuleKind === undefined && moduleKind === ModuleKind.Preserve)
         ) {
             // When we emit as an ES module, generate an `import` declaration that uses named imports for helpers.
             // If we cannot determine the implied module kind under `module: preserve` we assume ESM.

src/compiler/moduleSpecifiers.ts

@@ -513,7 +513,7 @@ function computeModuleSpecifiers(
             info,
             compilerOptions,
             host,
-            options.overrideImportMode || importingSourceFile.impliedNodeFormat,
+            options.overrideImportMode,
             preferences,
             /*pathsOnly*/ modulePath.isRedirect || !!specifier,
         );

tests/baselines/reference/ctsFileInEsnextHelpers.errors.txt

@@ -0,0 +1,9 @@
+notmodule.cts(1,23): error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
+
+
+==== notmodule.cts (1 errors) ====
+    export async function foo() {
+                          ~~~
+!!! error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
+      await 0;
+    }

tests/baselines/reference/ctsFileInEsnextHelpers.js

@@ -0,0 +1,24 @@
+//// [tests/cases/compiler/ctsFileInEsnextHelpers.ts] ////
+
+//// [notmodule.cts]
+export async function foo() {
+  await 0;
+}
+
+//// [notmodule.cjs]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.foo = foo;
+var tslib_1 = require("tslib");
+function foo() {
+    return tslib_1.__awaiter(this, void 0, void 0, function () {
+        return tslib_1.__generator(this, function (_a) {
+            switch (_a.label) {
+                case 0: return [4 /*yield*/, 0];
+                case 1:
+                    _a.sent();
+                    return [2 /*return*/];
+            }
+        });
+    });
+}

tests/baselines/reference/ctsFileInEsnextHelpers.symbols

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/ctsFileInEsnextHelpers.ts] ////
+
+=== notmodule.cts ===
+export async function foo() {
+>foo : Symbol(foo, Decl(notmodule.cts, 0, 0))
+
+  await 0;
+}

tests/baselines/reference/ctsFileInEsnextHelpers.types

@@ -0,0 +1,13 @@
+//// [tests/cases/compiler/ctsFileInEsnextHelpers.ts] ////
+
+=== notmodule.cts ===
+export async function foo() {
+>foo : () => Promise<void>
+>    : ^^^^^^^^^^^^^^^^^^^
+
+  await 0;
+>await 0 : 0
+>        : ^
+>0 : 0
+>  : ^
+}

tests/cases/compiler/ctsFileInEsnextHelpers.ts

@@ -0,0 +1,8 @@
+// @module: es2015
+// @importHelpers: true
+// @noTypesAndSymbols: true
+
+// @Filename: notmodule.cts
+export async function foo() {
+  await 0;
+}