Front-end web developers face challenges when using common “asynchronous” requests. These requests, such as fetching a URL or reading a file, often lead to complicated code, especially when performing multiple actions in a row. How can we make this easier for developers?

Javascript Promises are a new tool that simplifies asynchronous code, converting a tangle of callbacks and event handlers into simple, straightforward code such as: fetch(url).then(decodeJSON).then(addToPage)...

Promises are used by many new web standards, including Service Worker, the Fetch API, Quota Management, Font Load Events,Web MIDI, and Streams.

We’ve just opened up a online course on Promises, built in collaboration with Udacity. This brief course, which you can finish in about a day, walks you through building an “Exoplanet Explorer” app that reads and displays live data using Promises. You’ll also learn to use the Fetch API and finally kiss XMLHttpRequest goodbye!