The dangers of using ExtJS on a big project with RoR?

Question

We are developing a considerably big application using Ruby on Rails framework (CRM system) and are considering to rewrite it to use ExtJS so that Rails would just do the data handling, while ExtJS would do all the browser heavylifting in a desktop-like manner.

Anyone has some experience and hints about what would be the best approach? Is ExtJS mature enough to be used in relatively big (and complex) applications? And what about the Rails part - what would be the best approach here?

EDIT:

Just to make it clear. I would prefer to do it in such a way that all the javascript client side application code is loaded at once (at the start up of the application, optimally as one compressed js file) and then just use ajax to send data to and from Rails app. Also, it would be nice to have ERB available for dynamic generation of the Ext apliccation elements.

Answer 1

I currently have an extremely large, desktop style app written in ExtJS. It used to run on top of Perl's Catalyst MVC framework, but once the entire View layer was converted to an ExtJS based desktop I started migrating to Ruby on Rails models and controllers. It is equally as fast, if not faster, and easier to maintain and has a much smaller code base.

• Make sure that you set your active record config to not include the root name of the model in the json, so that Ext's JsonStore has no problem reading the records. There is an option on ActiveRecord BASE called include_root_in_json you have to set to false.

• Make sure that you properly define your Application classes in Ext and maximize code re-use and you are going to want some sort of method to clean up unused nodes in the DOM. Javascript performance can be a real pain unless you are using the latest versions of Safari or Firefox 3.1.

• You probably will want some sort of caching method for data on the server to be served to your application in JSON format at the time the page is loaded. This will cut down on the number of round trips via Ajax.

• Definitely make use of Ext's WindowManager and StoreManager objects, or roll your own from Ext.util.MixedCollection

• Develop your code in separate, managable files, then have a build process which combines them into a single file, and then run YUI's compressor or Dean Edwards Packer on it to compress / obfuscate the file. Serve all JS and CSS in their own single files, including the Ext supplied ones.