Re : Listen for change on model List aliased to controls options object

For the control to listen to events using the "{property} change" syntax, property must be defined on this.options before the controller's init() gets called.

One way to ensure it's in the right place before init() is to set it inside setup():

1. can.Control.extend({
2.       setup: function($el, options) {
3.             options.stateParams = options.data.stateParams;
4.             options.foo = options.foo || defaultValueFromSomewhere;
   
5.             // etc. Whatever logic you need to fill in options.yourProperty
6. 
   
7.             // make sure to call the parent's setup(), or bad things will happen
   
8.             return this._super.apply(this, arguments);
   
9.       },
10.       // etc
11. 
    
12.       // Then, so long as stateParams and foo are observable:
    
13.       '{stateParams} change': function() { ... },
14.       '{foo} change': function() { ... }
15. });
    

Edit: Oops -- apparently the parent's setup() is responsible for setting up the event bindings for "{property} change" callbacks, not init() as I thought above. This is mentioned at the bottom of the docs for setup().