title: Backbone.js: how to unbind from events, on model remove
body: <p>in backbone we have an app that uses an event Aggregator, located on the <code>window.App.Events</code>
  now, in many views, we bind to that aggregator, and i manually wrote a destroy function on a view, which handles unbinding from that event aggregator and then removing the view. (instead of directly removing the view).</p>
  
  <p>now, there were certain models where we needed this functionality as well, but i can't figure out how to tackle it.</p>
  
  <p>certain models need to bind to certain events, but maybe i'm mistaken but if we delete a model from a collection it stays in memory due to these bindings to the event aggregator which are still in place. </p>
  
  <p>there isn't really a remove function on a model, like a view has.
  so how would i tacke this?</p>
  
  <p><strong>EDIT</strong>
  on request, some code example.</p>
  
  <pre><code>App = {
      Events: _.extend({}, Backbone.Events)
  };
  
  var User = Backbone.Model.extend({
  
      initialize: function(){
          _.bindAll(this, 'hide');
          App.Events.bind('burglar-enters-the-building', this.hide);
      },
  
      hide: function(burglarName){
          this.set({'isHidden': true});
          console.warn("%s is hiding... because %s entered the house", this.get('name'), burglarName);
      }
  
  });
  
  var Users = Backbone.Collection.extend({
  
      model: User
  
  });
  
  var House = Backbone.Model.extend({
  
      initialize: function(){
          this.set({'inhabitants': new Users()});
      },
  
      evacuate: function(){
          this.get('inhabitants').reset();
      }
  
  });
  
  
  
  $(function(){
  
      var myHouse = new House({});
  
      myHouse.get('inhabitants').reset([{id: 1, name: 'John'}, {id: 1, name: 'Jane'}]);
  
      console.log('currently living in the house: ', myHouse.get('inhabitants').toJSON());
  
      App.Events.trigger('burglar-enters-the-building', 'burglar1');
  
      myHouse.evacuate();
  
      console.log('currently living in the house: ', myHouse.get('inhabitants').toJSON());
  
      App.Events.trigger('burglar-enters-the-building', 'burglar2');
  
  });​
  </code></pre>
  
  <p>view this code in action on jsFiddle (output in the console): <a href="http://jsfiddle.net/saelfaer/szvFY/1/">http://jsfiddle.net/saelfaer/szvFY/1/</a></p>
  
  <p>as you can see, i don't bind to the events on the model, but to an event aggregator.
  unbinding events from the model itself, is not necessary because if it's removed nobody will ever trigger an event on it again. but the eventAggregator is always in place, for the ease of passing events through the entire app.</p>
  
  <p>the code example shows, that even when they are removed from the collection, they don't live in the house anymore, but still execute the hide command when a burglar enters the house.</p>