Using Jest with ES Modules (Without Babel)

index.js

export default () => ({});

index.spec.js

import { fileURLToPath } from 'url';
import lib from '../';

// The `__dirname` psuedo-global is not available when using es-modules.
// The following can be used as a replacement.
const dirname = fileURLToPath(new URL('./', import.meta.url));

describe('lib', () => {
  it('is a function', () => {
    expect(lib).toBeFunction();
  });
});

jest.config.cjs

module.exports = {
  setupFilesAfterEnv: ['jest-extended'],
  transform: {} // <-- Important because it instructs Jest not to perform any transformations on code
};

package.json

{
  "name": "jest-with-es-modules",
  "type": "module",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "NODE_OPTIONS=--experimental-vm-modules jest --watchAll --verbose"
  },
  "devDependencies": {
    "jest": "^27.4.5",
    "jest-extended": "^1.2.0"
  }
}