JavaScript

Callback

Definition

A function passed as an argument to another function, to be executed later. Callbacks are the foundation of asynchronous JavaScript and are used extensively in event handling and array methods.

Code Example

Javascript

Tip: Modify the code above and click “Run” to see the results

Learn More

Fundamentals tutorials Async tutorials

Related Terms

Promise

An object representing the eventual completion or failure of an asynchronous operation. A Promise is in one of three states: pending, fulfilled, or rejected. Promises can be chained with .then() and .catch().

Async/Await

Syntactic sugar built on top of Promises that makes asynchronous code look and behave like synchronous code. async functions always return a Promise, and await pauses execution until a Promise resolves.

Higher-Order Function

A function that either takes one or more functions as arguments, returns a function, or both. Common examples include map, filter, reduce, and forEach.