Jest Mock Any Property on Window Utility - with automatic cleanup

README.md

Jest Mock Any Property on Window Utility - with automatic cleanup.

mock-window-property.js

export default const mockWindowProperty = (property, value) => {
  const { [property]: originalProperty } = window;
  delete window[property];
  beforeAll(() => {
    Object.defineProperty(window, property, {
      configurable: true,
      writable: true,
      value,
    });
  });
  afterAll(() => {
    window[property] = originalProperty;
  });
};

test.js

import mockWindowProperty from './mock-window-property'

describe('my test', () => {
  mockWindowProperty('localStorage', {
    setItem: jest.fn(),
    getItem: jest.fn(),
    removeItem: jest.fn(),
  });
  it('works as expected', () => {
   window.localStorage.setItem('abc');
   expect(window.localStorage.setItem).toHaveBeenCalledWith('abc');
  });
});