Using Promises Instead of Callbacks

Stop using nested callbacks for async function calls in JavaScript!
https://blog.jcoglan.com/2013/03/30/callbacks-are-imperative-promises-are-functional-nodes-biggest-missed-opportunity/

A detailed comparison between various implementations of Promise:
http://complexitymaze.com/2014/03/03/javascript-promises-a-comparison-of-libraries/

Bluebird is albeit the fastest Promise implementation in the market.
https://github.com/petkaantonov/bluebird

JQuery already uses Promise in its async operations, e.g., get, post, ajax, etc.

Scala also has Promise, aka Future:
http://docs.scala-lang.org/overviews/core/futures.html