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Promises are one of the most important concepts in modern JavaScript development. As we build increasingly complex web applications with lots of asynchronous operations, promises provide an elegant way to handle asynchronous code without callback hell.
In this article, we’ll cover the basics of promises in JavaScript. We’ll learn:
- What promises are and why they’re useful
- How to create, resolve, and handle promises
- Chaining promises for sequential async logic
- Common promise methods like
.then(),.catch(),.finally() - Using async/await syntactic sugar with promises
By the end, you’ll have a solid grasp on leveraging promises to write cleaner async JavaScript code.
What is a Promise?
A promise represents an asynchronous operation that hasn’t completed yet, but is expected to in the future. It essentially allows you to associate handlers to the eventual success or failure of this operation.
Promises can have three possible states:
- Pending - Initial state, neither fulfilled nor rejected
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