feat: added an option to disable ts-node

CHANGELOG.md

@@ -11,6 +11,7 @@
 - `[jest-config]` [**BREAKING**] Update `testMatch` and `testRegex` default option for supporting `mjs`, `cjs`, `mts`, and `cts` ([#14584](https://github.com/jestjs/jest/pull/14584))
 - `[jest-config]` Loads config file from provided path in `package.json` ([#14044](https://github.com/facebook/jest/pull/14044))
 - `[jest-config]` Allow loading `jest.config.cts` files ([#14070](https://github.com/facebook/jest/pull/14070))
+- `[jest-config]` Added an option to disable `ts-node` typechecking ([#15161](https://github.com/jestjs/jest/pull/15161))
 - `[@jest/core]` Group together open handles with the same stack trace ([#13417](https://github.com/jestjs/jest/pull/13417), & [#14789](https://github.com/jestjs/jest/pull/14789))
 - `[@jest/core]` Add `perfStats` to surface test setup overhead ([#14622](https://github.com/jestjs/jest/pull/14622))
 - `[@jest/core]` [**BREAKING**] Changed `--filter` to accept an object with shape `{ filtered: Array<string> }` to match [documentation](https://jestjs.io/docs/cli#--filterfile) ([#13319](https://github.com/jestjs/jest/pull/13319))

docs/Configuration.md

@@ -59,6 +59,8 @@ export default async (): Promise<Config> => {
 
 To read TypeScript configuration files Jest requires [`ts-node`](https://npmjs.com/package/ts-node). Make sure it is installed in your project.
 
+To read configuration files without typechecking, You can set `JEST_CONFIG_TRANSPILE_ONLY` environment variable to `true` (case insensitive).
+
 :::
 
 The configuration also can be stored in a JSON file as a plain object:

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

@@ -76,12 +76,42 @@
 test('it does type check the config', () => {
   writeFiles(DIR, {
     '__tests__/a-giraffe.js': "test('giraffe', () => expect(1).toBe(1));",
-    'jest.config.ts': 'export default { testTimeout: "10000" }',
+    'jest.config.ts': `
+      import {Config} from 'jest';
+      const config: Config = { testTimeout: "10000" };
+      export default config;
+    `,
     'package.json': '{}',
   });
 
   const {stderr, exitCode} = runJest(DIR, ['-w=1', '--ci=false']);
-  expect(stderr).toMatch('must be of type');
+  expect(stderr).toMatch(
+    "TS2322: Type 'string' is not assignable to type 'number'.",
+  );
+  expect(stderr).not.toMatch('Option "testTimeout" must be of type:');
+  expect(exitCode).toBe(1);
+});
+
+test('it can ignore type errors the config', () => {
+  writeFiles(DIR, {
+    '__tests__/a-giraffe.js': "test('giraffe', () => expect(1).toBe(1));",
+    'jest.config.ts': `
+      import {Config} from 'jest';
+      const config: Config = { testTimeout: "10000" };
+      export default config;
+    `,
+    'package.json': '{}',
+  });
+
+  const {stderr, exitCode} = runJest(DIR, ['-w=1', '--ci=false'], {
+    env: {
+      JEST_CONFIG_TRANSPILE_ONLY: 'true',
+    },
+  });
+  expect(stderr).not.toMatch(
+    "TS2322: Type 'string' is not assignable to type 'number'.",
+  );
+  expect(stderr).toMatch('Option "testTimeout" must be of type:');
   expect(exitCode).toBe(1);
 });
 

packages/jest-config/src/readConfigFileAndSetRootDir.ts

@@ -6,6 +6,7 @@
  */
 
 import * as path from 'path';
+import {isNativeError} from 'util/types';
 import * as fs from 'graceful-fs';
 import parseJson = require('parse-json');
 import stripJsonComments = require('strip-json-comments');
@@ -124,9 +125,14 @@ async function registerTsNode(): Promise<Service> {
       moduleTypes: {
         '**': 'cjs',
       },
+      transpileOnly:
+        process.env.JEST_CONFIG_TRANSPILE_ONLY?.toLowerCase() === 'true',
     });
-  } catch (error: any) {
-    if (error.code === 'ERR_MODULE_NOT_FOUND') {
+  } catch (error) {
+    if (
+      isNativeError(error) &&
+      (error as NodeJS.ErrnoException).code === 'ERR_MODULE_NOT_FOUND'
+    ) {
       throw new Error(
         `Jest: 'ts-node' is required for the TypeScript configuration files. Make sure it is installed\nError: ${error.message}`,
       );