observable_object_proxy.js

Ember.ObservableObjectProxy = Ember.Object.extend({
  init: function() {
    this._super();
    Ember.defineProperty(this, 'properties');
    this.set('properties', {});
  },

  unknownProperty: function(property) {
    return this.get('properties.'+property);
  },

  setUnknownProperty: function(property, value) {
    this.set('properties.'+property, value);
    this.notifyPropertyChange('@each');
  }
}