Björn Rixman bjrn

This article has been given a more permanent home on my blog. Also, since it was first written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.

You're Missing the Point of Promises

Promises are a software abstraction that makes working with asynchronous operations much more pleasant. In the most basic definition, your code will move from continuation-passing style:

getTweetsFor("domenic", function (err, results) {
 // the rest of your code goes here.

tl;dr

If you must nest functions in a way that requires access to multiple this', alias outer this to something meaningful - describe the value it's holding. Treat this as the invisible first argument.

In general though, avoiding the situation (nested functions and frivolous use of this) will frequently produce clearer results.

Naming `this` in nested functions

I was accidentally included in a discussion on how to best name this in nested functions in JavaScript. +1's were given to this suggestion of using _this.

Giving style advice on naming nested this without a meaningful context isn't too helpful in my opinion. Examples below have been altered to have at least some context, although a completely contrived and stupid one.

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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