What is Jest mocking and spying?

Can you explain what Jest mocking and spying is?

Sure! Jest mocking allows you to replace a function with a mock implementation, while spying lets you track calls to a function without changing its behavior.

How do I create a mock function in Jest?

You can create a mock function using jest.fn(). For example, const myMock = jest.fn();.

What’s the difference between a mock and a spy?

A mock function replaces the original function with a new implementation, while a spy wraps the original function to track calls without altering its behavior.

Can I use mocks and spies together?

Yes, you can use them together! You can spy on a function and also mock its implementation if needed.