Jest mocking reference error

Question

I\'m trying to use the following mock:

const mockLogger = jest.fn();

jest.mock(\"./myLoggerFactory\", () => (type) => mockLogger);

but m

Answer 1

I want to improve last answer with an example of code working:

import { getCookie, setCookie } from '../../utilities/cookies';

jest.mock('../../utilities/cookies', () => ({
  getCookie: jest.fn(),
  setCookie: jest.fn(),
}));
// Describe(''...)
it('should do something', () => {
    const instance = shallow(<SomeComponent />).instance();

    getCookie.mockReturnValue('showMoreInfoTooltip');
    instance.callSomeFunc();

    expect(getCookie).toHaveBeenCalled();
});

Answer 2

The problem is that jest.mock are hoisted to at the begin of the file on run time so const mockLogger = jest.fn(); is run afterwards.

To get it work you have to mock first, then import the module and set the real implementation of the spy:

//mock the module with the spy
jest.mock("./myLoggerFactory", jest.fn());
// import the mocked module
import logger from "./myLoggerFactory"

const mockLogger = jest.fn();
//that the real implementation of the mocked module
logger.mockImplementation(() => (type) => mockLogger)