Backbone multimodel proof of concept

multiModelExample.js

    // make sure underscore.js & backbone.js included above
    
    $ = {ajax: function(){
        console.log('BAM!');
        console.dir(arguments);
    }}
    
    var BaseModel = Backbone.Model.extend({
        url: 'whatever',
        save: function(attributes, options){
            console.log('Im saved');
            Backbone.Model.prototype.save.call(this, attributes || this.attributes, options);
        },
        diff: function(){
            
        }
    });
    
    var BaseCollection = Backbone.Collection.extend({
        save: function(){
            _.each(this.models, function(m){
                m.save();
            });
        }
    });
    
    
    var ModelA = BaseModel.extend({});
    var ModelB = BaseModel.extend({});
    var ModelC = BaseModel.extend({});
        
    var MultiModel = BaseModel.extend({
        modelsMap: {},
        set: function(attributes, options){
            var that = this;
            _.each(attributes, function(v,k){
                attributes[k] = k in that.modelsMap ? new that.modelsMap[k](v) : v; // TODO: smart setter
            });
            
            BaseModel.prototype.set.call(this, attributes, options);
        },
        toJSON: function(){
            var result = _.clone(this.attributes);
            _.each(result, function(v,k){
                v['toJSON'] ? result[k] = v.toJSON() : '';
            });
            return result;
        },
        save: function(attributes, options){
            console.log('multi model save:');
            attributes = attributes || this.attributes;
            
            var newAttr = _.clone(attributes);
            
            _.each(attributes, function(v,k){
                if(v['save']) {
                    v.save.call(v);
                    delete newAttr[k];
                }
            });
            
            if(JSON.stringify(newAttr) != '{}') {
                BaseModel.prototype.save.call(this, newAttr, options);
            }
        }
    });
    
    var MyMultiModel = MultiModel.extend({
        modelsMap: {
            a: ModelA,
            b: ModelB,
            c: MultiModel.extend({
                modelsMap: {
                    types: ModelC
                }
            }),
            d: BaseCollection.extend({
                model: ModelC
            })
        },
        url: 'myltiModel'
    });
        
    var MyCollection = BaseCollection.extend({
        model: MyMultiModel,
        url: 'myCollection'
    });
    
    var c = new MyCollection;
    c.add({
        a: {a:1, b:2, c:3},
        b: {key: 'value'},
        c: {types: {t1:11, t2:22, t3:33}},
        d: [ {a:1}, {b:2}, {c:3} ],
        ops: 'blabla'
    });
     
    c.save(); // THERE IS A BUG: MyMultiModel don't save {ops: 'blabla'} itself :(
     
    //console.log( c.at(0).get('c').get('types').get('t1') );
    console.log( '\n---- c.toJSON(): -----' );
    console.dir( c.toJSON() );