What is promise chaining in JavaScript?

What is promise chaining in JavaScript?

Promise chaining is a technique in JavaScript that allows you to execute asynchronous operations in sequence. Instead of nesting callbacks, you can return a promise from a .then() method, which can be followed by another .then().

Can you give me an example of promise chaining?

Sure! Here's a simple example:

fetch('https://api.example.com/data')
  .then(response => response.json())
  .then(data => {
    console.log(data);
    return fetch('https://api.example.com/other-data');
  })
  .then(otherData => console.log(otherData));

In this example, the second fetch only happens after the first one is completed.

What happens if one of the promises fails?

If a promise in the chain fails, the control will jump to the nearest .catch() method. You can handle errors gracefully this way.

How can I handle multiple promises at once?

You can use Promise.all() to handle multiple promises concurrently. It takes an array of promises and resolves when all of them are fulfilled.