Posts Tagged ‘observer pattern’

JavaScript Architecture: Backbone.js Events


Updated Aug 11, 2012 to reflect current library versions.

Backbone.js is an MVC framework for JavaScript applications (although some legitimately argue it’s not technically MVC). Its purpose is to provide structure to your application so it can be modular, decoupled, and scalable. If you’re not sure why you may need an application framework, please read JavaScript Architecture: The Basics first. Backbone is not a dom manipulation utility, templating engine, or UI component library.

Backbone.js files and documentation can be found here or you can get involved with the source and community at GitHub. At the time of this writing, the unminified, documented code is only about 1,200 lines long so don’t be afraid to dig in and walk through the code itself. Heck, there’s even an annotated version.


At the heart of every RIA is the observer pattern (otherwise known as the publisher/subscriber pattern). The observer pattern is a design pattern that allows an object to be notified when another object has something to say, or in other words, has an event which it wishes to broadcast.

DOM elements (links, buttons, containers, etc.) already have the observer pattern natively baked in which is why you can watch for when a button is clicked without using libraries like Backbone or jQuery. However, there are times where we want our own JavaScript objects to trigger/dispatch events and we would normally have to write the implementation of this pattern ourselves. That’s where Backbone comes in. Backbone has this code for you in Backbone.Events. Continue reading »