How can I use advanced assertions in Jest?

How can I use advanced assertions in Jest?

You can use advanced assertions in Jest by utilizing matchers like toEqual, toBe, and custom matchers for more complex scenarios.

Can you give me an example of a custom matcher?

Sure! You can create a custom matcher like this: expect.extend({ toBeEven(received) { const pass = received % 2 === 0; return { pass, message: () => Expected ${received} to be even }; } });.

How do I test asynchronous code with Jest?

You can test asynchronous code using async/await or by returning a promise. Just make sure to use await with your assertions.

What about testing error handling?

For error handling, you can use expect().rejects.toThrow() for promises or expect().toThrow() for synchronous functions.