tslib: "TypeError: Cannot redefine property:" Bug Appears To Have Returned

Bug Report

Version 1.13.0 fixed the bug referenced here:
microsoft/tslib#102

But, in moving to either 2.0.0 or 2.1.0 - the bug is happening again.

🔎 Search Terms

tslib
TypeError: Cannot redefine property:

🕗 Version & Regression Information

This is fixed in 1.13.0 - but broke again in both version 2.0.0 and 2.1.0

• This prevents us from using tsconfig aliased paths in conjuncture with jest spyOn(..). We can work around this by providing the relative paths instead of the paths as determined by the tsconfig - but this is against our code policy.
• This changed between versions 1.13.0 and 2.0.0

💻 Code

internal/business functions/directories scrubbed from the following code snippet - but in case this makes it more clear

import * as Utils from '@some-platform/core/libs/utils/support';

describe( 'test tslib compatibility with aliased imports', () => {

	it( 'jest spyOn', async () => {

		// test that we don't get the following error (tslib 2.0 and 2.1 will cause this):
		// TypeError: Cannot redefine property: foobar
		// at Function.defineProperty (<anonymous>)
		const foobarSpy = jest.spyOn( Utils, 'foobar' );

		const imported = await Utils.foobar( );

		expect( foobarSpy ).toHaveBeenCalled();
	} );
} );

🙁 Actual behavior

We're forced to use relative paths when we use jest spyOn type functionality - instead of the aliased paths from tsconfig.

🙂 Expected behavior

We shouldn't have to update our paths to be relative paths.

[victorigualada]

I'm having the same issue when mocking node's path library return value:

import * as path from 'path';

describe('test path', () => {
  it('should mock path.resolve', () => {
    const pathSpy = jest.spyOn(path, 'resolve').mockReturnValue('/');
    path.resolve('my/unexisting/path');
    expect(pathSpy).toHaveBeenCalledWith('my/unexisting/path');
  });
});

Will throw: TypeError: Cannot redefine property: resolve

Changing the way that Typescript imports the module:

import path from 'path'

instead of

import * as path from 'path'

With this change the test passes but a jest error is thrown, not related to this issue:

Test suite failed to run

    Cannot find module 'jest-util'
    Require stack:
    - /test-project/node_modules/jest-runtime/build/index.js
    - /test-project/node_modules/@jest/core/build/cli/index.js
    - /test-project/node_modules/@jest/core/build/jest.js
    - /test-project/node_modules/jest-cli/build/cli/index.js
    - /test-project/node_modules/jest-cli/bin/jest.js
    - /test-project/node_modules/jest/bin/jest.js

      at _jestUtil (node_modules/jest-runtime/build/index.js:164:16)

So consider importing just what you need (named imports) instead of importing all (*) from a module.