fix(ts-config): pass moduleTypes to enforce CJS for TS config file

CHANGELOG.md

@@ -17,8 +17,9 @@
 
 - `[expect]` Move typings of `.not`, `.rejects` and `.resolves` modifiers outside of `Matchers` interface ([#12346](https://github.com/facebook/jest/pull/12346))
 - `[expect]` Expose `AsymmetricMatchers` and `RawMatcherFn` interfaces ([#12363](https://github.com/facebook/jest/pull/12363))
-- `[jest-environment-jsdom]` Make `jsdom` accessible to extending environments again ([#12232](https://github.com/facebook/jest/pull/12232))
 - `[jest-config]` Correctly detect CI environment and update snapshots accordingly ([#12378](https://github.com/facebook/jest/pull/12378))
+- `[jest-config]` Pass `moduleTypes` to `ts-node` to enforce CJS when transpiling ([#12397](https://github.com/facebook/jest/pull/12397))
+- `[jest-environment-jsdom]` Make `jsdom` accessible to extending environments again ([#12232](https://github.com/facebook/jest/pull/12232))
 - `[jest-jasmine2, jest-types]` [**BREAKING**] Move all `jasmine` specific types from `@jest/types` to its own package ([#12125](https://github.com/facebook/jest/pull/12125))
 
 ### Chore & Maintenance

e2e/__tests__/esmConfigFile.test.ts

@@ -5,6 +5,9 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import {resolve} from 'path';
+import execa = require('execa');
+import {existsSync} from 'graceful-fs';
 import {onNodeVersions} from '@jest/test-utils';
 import {getConfig} from '../runJest';
 
@@ -44,4 +47,34 @@ onNodeVersions('>=12.17.0', () => {
       name: 'Config from js file',
     });
   });
+
+  describe('typescript', () => {
+    beforeAll(async () => {
+      // the typescript config test needs `@jest/types` to be built
+      const cwd = resolve(__dirname, '../../');
+      const typesPackageDirectory = 'packages/jest-types';
+
+      const indexDTsFile = resolve(
+        cwd,
+        typesPackageDirectory,
+        'build/index.d.ts',
+      );
+
+      if (!existsSync(indexDTsFile)) {
+        await execa('tsc', ['-b', typesPackageDirectory], {cwd});
+      }
+    }, 60_000);
+
+    test('reads config from ts file when package.json#type=module', () => {
+      const {configs} = getConfig('esm-config/ts', [], {
+        skipPkgJsonCheck: true,
+      });
+
+      expect(configs).toHaveLength(1);
+      expect(configs[0].displayName).toEqual({
+        color: 'white',
+        name: 'Config from ts file',
+      });
+    });
+  });
 });

e2e/esm-config/ts/__tests__/test.js

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+test('dummy test', () => {
+  expect(1).toBe(1);
+});

e2e/esm-config/ts/jest.config.ts

@@ -0,0 +1,15 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import type {Config} from '@jest/types';
+
+const config: Config.InitialOptions = {
+  displayName: 'Config from ts file',
+  testEnvironment: 'node',
+};
+
+export default () => config;

e2e/esm-config/ts/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

e2e/runJest.ts

@@ -266,13 +266,18 @@ export function getConfig(
   configs: Array<Config.ProjectConfig>;
   version: string;
 } {
-  const {exitCode, stdout} = runJest(
+  const {exitCode, stdout, stderr} = runJest(
     dir,
     args.concat('--show-config'),
     options,
   );
 
-  expect(exitCode).toBe(0);
+  try {
+    expect(exitCode).toBe(0);
+  } catch (error) {
+    console.error('Exit code is not 0', {stderr, stdout});
+    throw error;
+  }
 
   return JSON.parse(stdout);
 }

packages/jest-config/src/readConfigFileAndSetRootDir.ts

@@ -84,21 +84,7 @@ const loadTSConfigFile = async (
   configPath: Config.Path,
 ): Promise<Config.InitialOptions> => {
   // Register TypeScript compiler instance
-  try {
-    registerer ||= require('ts-node').register({
-      compilerOptions: {
-        module: 'CommonJS',
-      },
-    });
-  } catch (e: any) {
-    if (e.code === 'MODULE_NOT_FOUND') {
-      throw new Error(
-        `Jest: 'ts-node' is required for the TypeScript configuration files. Make sure it is installed\nError: ${e.message}`,
-      );
-    }
-
-    throw e;
-  }
+  await registerTsNode();
 
   registerer.enabled(true);
 
@@ -113,3 +99,30 @@ const loadTSConfigFile = async (
 
   return configObject;
 };
+
+async function registerTsNode(): Promise<Service> {
+  if (registerer) {
+    return registerer;
+  }
+
+  try {
+    const tsNode = await import('ts-node');
+    registerer = tsNode.register({
+      compilerOptions: {
+        module: 'CommonJS',
+      },
+      moduleTypes: {
+        '**': 'cjs',
+      },
+    });
+    return registerer;
+  } catch (e: any) {
+    if (e.code === 'ERR_MODULE_NOT_FOUND') {
+      throw new Error(
+        `Jest: 'ts-node' is required for the TypeScript configuration files. Make sure it is installed\nError: ${e.message}`,
+      );
+    }
+
+    throw e;
+  }
+}