I am developing an \"art gallery\" app.
Feel free to pull down the source on github and play around with it.
Plunker with full
One of the least documented feature of Angular is its Directive Controllers ( though it is on the front page of www.angularjs.org - Tabs ).
Here is a modified plunker that makes use of this mechanism.
http://plnkr.co/edit/NmV3m6DZFSpIkQOAjRRE
People do use Directive Controllers but it has been used ( and abused ) for things it probably was not meant for.
In the plunker above I have only modified the directives.js file. Directive controllers are a mechanism for communication between directives. Sometimes , it is not sufficient / easy to do everything in one directive. In this case, you have already created two directives but the right way to make them interact is through a directive controller.
I was not able to figure out when you wanted to prepend and when you wanted to append. I have only implemented "append" currently.
Also on a side note : If resources doesnt already implement promises, you can implement them yourself. It isnt really hard to do that. I noticed you are using a callback mechanism (which I wouldnt recommend ). You have already put in promises there but still you are using callbacks which I was not able to understand why.
Does this provide a proper solution to your problem ?
For documentation see http://docs.angularjs.org/guide/directive > Directive Definition Object > controller.