getting console.error during testing in jest of javascript code example

Example: how to spy on console.error jest

beforeAll(() => {
    // Create a spy on console (console.log in this case) and provide some mocked implementation
    // In mocking global objects it's usually better than simple `jest.fn()`
    // because you can `unmock` it in clean way doing `mockRestore` 
    jest.spyOn(console, 'log').mockImplementation(() => {});
  });
afterAll(() => {
    // Restore mock after all tests are done, so it won't affect other test suites
    console.log.mockRestore();
  });
afterEach(() => {
    // Clear mock (all calls etc) after each test. 
    // It's needed when you're using console somewhere in the tests so you have clean mock each time
    console.log.mockClear();
  });