Introduction:
JavaScript Promises are a powerful and essential feature in modern web development, providing a streamlined way to handle asynchronous operations. Introduced in ECMAScript 6 (ES6), promises simplify the management of asynchronous code, making it more readable and maintainable.
Promise:
Promise is an object representing the eventual completion or failure of an asynchronous operation and its resulting value. It has three states: pending, fulfilled, and rejected. A promise starts in the pending state and transitions to either fulfilled or rejected once the operation is completed.
Creating a Promise:
To create a promise, use the Promise constructor, which takes a function as its argument. This function, known as the executor, takes two parameters: resolve and reject. resolve is a function that, when called, transitions the promise to the fulfilled state, while reject transitions it to the rejected state.
const myPromise = new Promise((resolve, reject) => {
// Asynchronous operation
})
Chaining Promises:
Promises can be chained using the .then() method, which is called when the promise is fulfilled. This enables a sequence of asynchronous operations to be executed in a clear and readable manner.