we are evaluating the use of SenchaTouch 2 and ExtJS for a web application project. The project will have a desktop version (maybe ExtJS) and a touch version (maybe SenchaTouch).

A big part of logic have to be implemented in JS. GUI and platform independent logic: client/server communication, plugins to access our services (e.g. Authentication) or data handling etc.

So the question is: Is there a shared part, we can use for both plattforms? It seems, that a lot is equal, similiar or different. E.g. the class system seems to be equal, the store system is different. But the important point is, that the overlap is not defined. We do not want to build our software on our speculations .

ExtCore stucks at version 3 and is not part of ExtJS 4 and SenchaTouch 2. We found ext-core.js and ext-foundation.js in ExtJS 4. But both files are not available in SenchaTouch 2, as far as we see. Is this correct?

The current solutions for our requirements:
- Implementing the logic twice (with ExtJS and SenchaTouch)
- Use plain JS
- Use another Framework for shared functionality.

Are these the only valid solutions or is there an official and reliable way to implement things for both Sencha Frameworks?

Best regards