Async is a utility module which provides straight-forward, powerful functions for working with asynchronous JavaScript. Although originally designed for use with Node.js and installable via npm install --save async, it can also be used directly in the browser.
For Documentation, visit http://caolan.github.io/async/
For Async v1.5.x documentation, go HERE