Fix for the jest.config.ts compiler to not interfere with tsconfig.json files

CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Fixes
 
 - `[expect]` Fix `objectContaining` to work recursively into sub-objects ([#10508](https://github.com/facebook/jest/pull/10508))
+- `[jest-config]` Fix for the `jest.config.ts` compiler to not interfere with `tsconfig.json` files
 - `[jest-message-util]` Update to work properly with Node 15 ([#10660](https://github.com/facebook/jest/pull/10660))
 - `[jest-mock]` Allow to mock methods in getters (TypeScript 3.9 export) ([#10156](https://github.com/facebook/jest/pull/10156))
 

e2e/__tests__/jest.config.js.test.ts

@@ -10,7 +10,7 @@ import {wrap} from 'jest-snapshot-serializer-raw';
 import runJest from '../runJest';
 import {cleanup, extractSummary, writeFiles} from '../Utils';
 
-const DIR = path.resolve(__dirname, '../jest.config.js');
+const DIR = path.resolve(__dirname, '../jest-config-js');
 
 beforeEach(() => cleanup(DIR));
 afterAll(() => cleanup(DIR));

e2e/__tests__/jest.config.ts.test.ts

@@ -10,7 +10,7 @@ import {wrap} from 'jest-snapshot-serializer-raw';
 import runJest from '../runJest';
 import {cleanup, extractSummary, writeFiles} from '../Utils';
 
-const DIR = path.resolve(__dirname, '../jest.config.ts');
+const DIR = path.resolve(__dirname, '../jest-config-ts');
 
 beforeEach(() => cleanup(DIR));
 afterAll(() => cleanup(DIR));
@@ -29,6 +29,21 @@ test('works with jest.config.ts', () => {
   expect(wrap(summary)).toMatchSnapshot();
 });
 
+test('works with tsconfig.json', () => {
+  writeFiles(DIR, {
+    '__tests__/a-giraffe.js': `test('giraffe', () => expect(1).toBe(1));`,
+    'jest.config.ts': `export default {testEnvironment: 'jest-environment-node', testRegex: '.*-giraffe.js'};`,
+    'package.json': '{}',
+    'tsconfig.json': '{ "compilerOptions": { "module": "esnext" } }',
+  });
+
+  const {stderr, exitCode} = runJest(DIR, ['-w=1', '--ci=false']);
+  const {rest, summary} = extractSummary(stderr);
+  expect(exitCode).toBe(0);
+  expect(wrap(rest)).toMatchSnapshot();
+  expect(wrap(summary)).toMatchSnapshot();
+});
+
 test('traverses directory tree up until it finds jest.config', () => {
   writeFiles(DIR, {
     '__tests__/a-giraffe.js': `

packages/jest-config/src/readConfigFileAndSetRootDir.ts

@@ -107,7 +107,11 @@ const loadTSConfigFile = async (
 
   // Register TypeScript compiler instance
   try {
-    registerer = require('ts-node').register();
+    registerer = require('ts-node').register({
+      compilerOptions: {
+        module: 'CommonJS',
+      },
+    });
   } catch (e) {
     if (e.code === 'MODULE_NOT_FOUND') {
       throw new Error(