Backbonejs, "Object #<Object> has no method apply" when setting model attribute inside a Collections.each

Question

Backbonejs, "Object #<Object> has no method apply" when setting model attribute inside a Collections.each

I made and initialized my model with the "change:status" event like this

Box = Backbone.Model.extend({
    initialize: function() {
      this.on('change:status', this.changed, this);
    },
    changed: function() {
      $('.changed').text('I changed'); // Testing if the 'change:status' is fired
    }
});

My Box collections is setup this way

BoxList = Backbone.Collection.extend({
    model: Box,
    initialize: function() {
       this.on('add', this.addOne, this);
       socket.on('box-status-change', this.boxStatusChanged, this);
    },
    boxStatusChanged: function(box) {
        Boxes.each(function(model) {
          if(model.get('changed') == box.changed) {
            model.set({status: 'changed'});
          }
        });
    },
    addOne: function.... // Some code removed
});

Boxes = new BoxList();

Checking in Chromes web developer tools, the attribute status was set to changed properly but an error Uncaught TypeError: Object #<Object> has no method 'apply' occured. The change:title event of the model was not fired. Is there something I miss when adding the event to the model?

By the way, I'm using the backbone-iosync.js for the Backbone.sync method...

node.js
backbone.js

Answer 1

Backbone uses an internal attribute called changed on models:

http://backbonejs.org/#Model-changed

changed model.changed
The changed property is the internal hash containing all the attributes that have changed since the last "change" event was triggered. Please do not update changed directly. Its state is maintained internally by set and change. A copy of changed can be acquired from changedAttributes.

Rename your callback to something else and that works

Box = Backbone.Model.extend({
    initialize: function() {
      this.on('change:status', this.changedState, this);
    },
    changedState: function() {
      console.log('changed');
    }
});

A Fiddle to reproduce your problem http://jsfiddle.net/NrTPk/ and a modified version http://jsfiddle.net/NrTPk/1/