mockESModule workaround for JEST 29.x

mock-esmodule.js

import * as path from 'path';
import * as url from 'url';

function forEachDeep(obj, cb, options = { depth: 6 }) {
  (function walk(value, property = undefined, parent = null, objPath = []) {
    return value && typeof value === 'object' && objPath.length <= options.depth
      ? Object.entries(value).forEach(([key, val]) =>
          walk(val, key, value, [...objPath, key])
        )
      : cb([property, value], parent, objPath);
  })(obj);
}

const NOOP = x => x;
export default async function mockESModule(
  moduleSpecifier,
  importMeta,
  factory = NOOP
) {
  let modulePath = moduleSpecifier;

  if (moduleSpecifier.startsWith('.')) {
    const metaPath = url.fileURLToPath(new URL('./', importMeta.url));
    modulePath = path.join(metaPath, moduleSpecifier);
  }

  const { jest } = importMeta;
  const module = await import(modulePath);

  const moduleCopy = { ...module };
  forEachDeep(moduleCopy, ([prop, value], obj) => {
    if (typeof value === 'function') {
      obj[prop] = jest.fn(value);
      // re-adding stinky dynamic custom properties which jest.fn() may has removed
      Object.assign(obj[prop], value);
    }
  });

  const moduleMock = factory(moduleCopy);
  jest.unstable_mockModule(moduleSpecifier, () => moduleMock);

  return moduleMock;
}

my-module.js

import someMagic from './some-magic.js';

export default function(){
  return someMagic() ? 'magic' : 'no magic';
}

my-module.spec.js

import { describe, it, jest } from '@jest/globals';
import mockESModule from './mock-esmodule.js';

// this will mock all functions exported from some-magic.js
const mockMagic = (await mockESModule('./some-magic.js', import.meta)).default;
// use import() in order to apply mocked version of dependencies
const myModule = (await import('./my-module.js')).default;

describe('modulename', () => {
  it('invokes the thing', () => {
    const result = myModule();
    expect(result).toBe('magic');
  });
  it('throws if magic is falsy', () => {
    mockMagic.mockImplementationOnce(() => false);
    expect(myModule).toBe('no magic');
    expect(mockMagic).toHaveBeenCalled();
  })
})

some-magic.js

export default function someMagic(){ return true }

Key components:
Mock via jest.unstable_mockModule() before import() - you have to use dynamic import() over static import
https://github.com/facebook/jest/blob/main/docs/ECMAScriptModules.md#module-mocking-in-esm

jest.unstable_mockModule('your-dependency', () => ({ default: jest.fn(() => true) }));
const moduleToBeTested = (await import('my-module-to-be-tested.js')).default;

Thanks for sharing, @booya2nd, this is very helpful! Would you be able to specify the license of this code?