The first two patterns we looked at in this series were Node.js callbacks and the Async module. While effective, those patterns are not the only ways of writing asynchronous code. Patterns built around concepts such as “deferreds” and “promises” were first introduced to the JavaScript community via third-party libraries like Q and Bluebird. Over time a native implementation of promises was added to ECMAScript, then implemented in V8, and later integrated into Node.js.

Promises are important to learn because many modules use them in their APIs. Also, they are integral to async functions, which I’ll cover in the next part of the series. This post will cover the basics of promises and demonstrate how they can be used to construct asynchronous applications.

Leave a Reply

Your email address will not be published. Required fields are marked *