How do I mock async functions in Jest?

How do I mock async functions in Jest?

You can use jest.fn() to create a mock function and then use mockResolvedValue or mockRejectedValue for async functions.

Can you show me an example of that?

Sure! Here's a simple example:

const fetchData = async () => {
  const response = await fetch('https://api.example.com/data');
  return response.json();
};

jest.mock('./fetchData');

fetchData.mockResolvedValue({ data: 'some data' });

What if the async function throws an error?

You can use mockRejectedValue to simulate an error. For example:

fetchData.mockRejectedValue(new Error('Failed to fetch'));

Is there a way to reset the mocks after each test?

Yes! You can use jest.clearAllMocks() in the afterEach block to reset the mocks.