Mojito uses callbacks for its asynchronous methods (for example in mojito.models.getData() and MojitProxy.invoke()).
I know YUI is developing Y.Promise and Y.Deferred at the moment (following the Promises/A spec). Could you consider doing the same for future releases? I know it involves rewriting a lot of code, but it makes mojito-projects structured in a much better way.
I would really appreciate. I find myself working with deep nested callbacks (mojito.models.getData() which make a call to MySQL multiple times) of their own. The code gets complicated this way. Promises would help.