Update: jQuery 3.0 has fixed the problems outlined below. It is truly Promises/A+ compliant. Yes, jQuery promises have serious and inherent problems. That said, since the article was written jQuery made significant efforts to be more Promises/Aplus complaint and they now have a .then method that chains. So even in jQuery returnsPromise().then(a).then(b) for promise returning … Read more
Let’s start with the general rule for using promises: Every function that does something asynchronous must return a promise Which functions are these in your case? It’s getPrayerInCat, the forEach callback, and Prayer.find. Hm, Prayer.find doesn’t return a promise, and it’s a library function so we cannot modify it. Rule 2 comes into play: Create … Read more
Resolve promises one after another (i.e. in sequence)?
Promises are not callbacks. A promise represents the future result of an asynchronous operation. Of course, writing them the way you do, you get little benefit. But if you write them the way they are meant to be used, you can write asynchronous code in a way that resembles synchronous code and is much more … Read more
The deferred antipattern (now explicit-construction anti-pattern) coined by Esailija is a common anti-pattern people who are new to promises make, I’ve made it myself when I first used promises. The problem with the above code is that is fails to utilize the fact that promises chain. Promises can chain with .then and you can return … Read more