How can I mock async data in my application?

How can I mock async data in my application?

You can use libraries like Jest or Sinon to create mock functions that simulate async data responses.

Can you show me an example using Jest?

Sure! You can use jest.fn() to create a mock function and return a promise. Here's a simple example: const fetchData = jest.fn(() => Promise.resolve('data'));.

What if I want to simulate an error?

You can modify the mock to return a rejected promise like this: const fetchData = jest.fn(() => Promise.reject(new Error('Error fetching data')));.

Thanks! Is there a way to test the loading state?

Yes! You can set up your component to show a loading state while the async function is called, and then update it based on the promise resolution.