The Promised Land: Untangling Async Spaghetti Code

When you want anything done involving I/O in JavaScript, you’re going to have to pony up a callback. When you want several async things done, in order, with proper error-handling, you might write a series of nested callbacks—but therein lies the path to madness. Understanding and refactoring your code becomes exponentially harder with the number of levels of indentation.

Fortunately, there are some simple techniques that can save you from nested callback hell. Among the most exciting of these are Promises.

Promises have been a part of jQuery since 1.5, but they haven’t yet gotten the love they deserve as a simple, elegant alternative to callback arguments. With Promises, you can write smaller callbacks and write more readable, reusable code.

This talk features material from my upcoming book, Async JavaScript.