Asynchronous JavaScript and Promises

Asynchronous JavaScript is a programming paradigm that allows code to run in the background without blocking the execution of other code. Asynchronous operations are typically used for tasks that take a long time to complete, such as fetching data from a server or processing large files.

In JavaScript, asynchronous operations are usually implemented using callbacks or promises. Callbacks are functions that are passed as arguments to other functions, and are executed when a task is complete. Promises are objects that represent the eventual completion (or failure) of an asynchronous operation, and can be used to chain together multiple asynchronous tasks.

Promises provide a more flexible and powerful way to handle asynchronous operations in JavaScript. Promises represent a future value that may not be available yet, and can be in one of three states: pending, fulfilled, or rejected. Promises can be chained together using the then() method, which takes a callback function that is executed when the promise is fulfilled, and returns a new promise that can be chained with another then() method.