Sencha Touch and ExtJS

Sencha Touch looks impressive, and ExtJS looks nice.

I am evaluating if I should use ExtJS or SproutCore for an upcoming app. Now that Sencha To开发者_开发技巧uch is in the mix, I wonder if I choose ExtJS, it'd be easier to port/migrate part of the app to mobile world.

Is that true? Would I be able to have the same code base for both ExtJS for desktop browsers and Sencha Touch for mobile devices?

If not how much different would the code base be?

Just came from an EXTJS meetup where one presentation was about Sencha Touch. An app was ported from the former to the latter -- it was claimed that ~40% code could be reused.

That said, it was also pointed out that Sencha Touch has heavy iphone look and feel, so if you want something more platform independent, you might want to consider Sproutcore (and its corresponding mobile framework).

If you have an ExtJs app, creating a touch version will definitely be easier than to use two different frameworks for desktop and mobile. Looking at the API, it seems that it looks and smells like ExtJS API, so your server code(that emits UI JSON) will be mostly the same.