Asynchronous JavaScript

In this module we take a look at asynchronous JavaScript, why it is important, and how it can be used to effectively handle potential blocking operations such as fetching resources from a server.

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Prerequisites

Asynchronous JavaScript is a fairly advanced topic, and you are advised to work through JavaScript first steps and JavaScript building blocks modules before attempting this.

Note: If you are working on a computer/tablet/other device where you don't have the ability to create your own files, you can try out (most of) the code examples in an online coding program such as JSBin or Glitch.

Guides

Introducing asynchronous JavaScript

In this article we'll see what synchronous and asynchronous programming are, why we often need to use asynchronous techniques, how asynchronous functions have historically been implemented in JavaScript, and what their problems are.

How to use promises

Here we'll introduce promises and show how to use promise-based APIs. We'll also introduce the async and await keywords.

Implementing a promise-based API

This article outlines how to implement your own promise-based API.

Introducing workers

Workers enable you to run certain tasks in a separate thread, to keep your main code responsive. In this article we'll rewrite a long-running synchronous function to use a worker.

Assessments

Sequencing animations

The assessment asks you to use promises to play a set of animations in a particular sequence.

See also