I built http://plunker.no.de/edit using Backbone.js and really have enjoyed the process. The addition of the sync event has really helped me out.

That being said, I think the most important abstraction that I introduced in this project and not in others was inspired by moviepilot.com's Chaplin project: https://github.com/moviepilot/chaplin

The revelation was to have a central mediator pub/sub mechanism. I used that central mechanism to allow different parts of the ui to declare intents. Each intent has a target that can handle that intent and (if appropriate) emit a corresponding event. The idea is that there is a single handler of each 'intent' and can be many handlers of 'event's. This is because each UI component doesn't necessarily know of the final receiver of the intent events. Keeps things nicely decoupled (so far at least!).

For example: https://github.com/ggoodman/stsh/blob/master/assets/js/views...

The Sidebar contains a list of filenames in the current 'plunk'. When the user clicks on a filename, an 'intent:activate' event is fired. When the user double-clicks an 'intent:rename' event is fired. Only once those changes have been handled and refired as 'event:activate' or 'event:rename' are they reflected in the UI.