Mocking moment() and moment().format using jest

Question

I\'m unable to mock moment() or moment().format functions. I have states where, currentDateMoment and currentDateFormatted ar

Answer 1

To Mock Moment().format(),startOf() , isValid() or isAfter() etc. Can refer below example.

jest.mock('moment', () => {
    
    const momentParams = {
        format: jest.fn(() => '10/04/2020'),
        startOf: jest.fn().mockReturnThis(),
        isAfter: jest.fn().mockReturnValue(true),
        isValid: jest.fn().mockReturnValue(true)
    };

   const fn = jest.fn(newMoment => {
        momentParams.format = jest.fn(() => newMoment);
        return momentParams;
   });

   return fn;
});

And last you can write a test case like this. eg.

 test('should returned mocked value for isAfter()', async () => {
    jest.spyOn(moment(), 'isAfter').mockReturnValue(false);
    const response = moment().isAfter();
    expect(response).toBe(false)
})