Backbone vs ExtJS

A lightweight view class is provided but there is no default templating method implemented. Because views are minimal it allows for much more freedom to implement views however you would like, and because of this freedom it's possible to write views to more uniquely adapt to a problem.

User interactions are done within an events object that allows these interactions to be segregated from the rest of the view code which makes the behavioral aspect of the view easier to read and manage.

Backbone can be combined with any library of your choosing, giving you the ultimate flexibility in creating customized solutions for unique projects. Even the only two backbone requirements, jQuery and underscore can be replaced with equivalent libraries like zepto or lo-dash.

Backbone has existed longer than most frameworks, and has a large following of users and projects using it as a framework.

Backbone collections and models are extended by underscore.js method allowing you to call underscore methods directly on the Backbone objects.

Backbone provides Model and Collection classes that provide strong analogs to restful resources. These strong analogs allow you to interface more naturally with the API, and makes it easier to write custom behaviors for more complicated API interactions.

Collections provide a variety of powerful manipulation methods that are integrated from the underscore library, that allow you to manipulate, sort, and filter collection data easily.

Because all the state is managed by Models and Controllers, and they are extendable objects, you can isolate all the state logic onto those objects allowing the rest of the application to not worry about it. The app is simplified to just taking in input to modify the Models and Controllers, and updating the views to reflect them, but none of the state needs to be a concern outside of the Model and Controller classes.

There is no “magic” happening below the surface: the source code is clear, readable and well commented. Backbone is also “lightweight” in the sense that it doesn’t require a ton of buy-in to use. It can be easily integrated into an existing page, and you can choose to only use certain components of the library (Views without Models or Collections, for example). While there are many frameworks that seem to be faster to get started with, Backbone’s lack of surprises, clear documentation, speed & flexibility make it a good fit for all types of apps.

Because Backbone is so simple, and the different components are very well isolated, it is very easy to extend the functionality of Backbone. If you're writing your own extended code it's easy to keep it separated out, and share with the community.

The community also has many plugins already available, which you can pick and choose to use to fit your programming style.

All Backbone classes extend an events class that allows for listening and triggering functionality. Because all classes implement events by default it is easier to provide asynchronous communication between objects, and it allows better abstraction of interaction so the event emitting object does not need to know the structure or existence of the receiving object.

Huge amount of widgets available, also easy to build custom widgets by extending the available components.

If you buy a license you can get professional support and premium forums. Support has short contact times and solutions are of great value.

ExtJS' documentation is very detailed and helpful. All concepts and parts of the framework are thoroughly explained.

Plugins are available for JetBrains, Eclipse and Visual Studio.

By using the packages and custom components, code can be reused very simply.

Anyone with basic JavaScript knowledge can start using this framework.

Forum support is available.

Eg: Sencha Architect.

Sencha Cmd, Sencha Inspector and some IDE plugins etc., are the tools which helps developers to speed up their development.