example with the parse method, for nesting a backbone collection inside a model

collectionandmodel.js

//example data format: 
var data = {
 "1": [ { data: 10 }, { data: 11}, { data: 12}],
 "2": value,
 "3": value2
};
var MyModel = Backbone.Model.extend({
  constructor: function() {
    arguments[1] = arguments[1] || {}; // ensure there's 'options'
    arguments[1].parse = true; // this model should always be parsed on intialization
    Backbone.Model.apply(this, arguments)
  }
  
  initialize: function() {
    this.crazyAssCollection = new Backbone.Collection();
  }
  
  parse: function(data) {
    // because we enforce parse in the constructor, 
    // this will always be called
    // on initialization
    
    // backbone users this on model.fetch() as well
    
    // add with merge makes sure old models are updated
    this.crazyAssCollection.add(data["1"], { merge: true }); 
    delete data["1"];
    return data;
  }
});

new MyModel(data);