How do I test asynchronous methods in JavaScript?

How do I test asynchronous methods in JavaScript?

You can use testing frameworks like Jest or Mocha. They provide utilities to handle async code.

Can you show me an example using Jest?

Sure! You can use async/await in your tests. For example:

test('fetches data', async () => {
  const data = await fetchData();
  expect(data).toBeDefined();
});

What if I want to test a promise directly?

You can return the promise from the test function. For example:

test('fetches data', () => {
  return fetchData().then(data => {
    expect(data).toBeDefined();
  });
});

Are there any best practices for testing async methods?

Yes! Always handle errors, use beforeEach for setup, and keep tests isolated to avoid side effects.