creationix

function shallowCopy(old) {
 var props = {};
 Object.getOwnPropertyNames(old).forEach(function (name) {
   props[name] = Object.getOwnPropertyDescriptor(old, name);
 });
 return Object.create(Object.getPrototypeOf(old), props);
}

// A very hard and dangerous to copy object
var obj = {

domenic

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written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.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.