Backbone sample environment

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.1.7/underscore-min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/backbone.js/0.5.3/backbone-min.js"></script>

JavaScript

window.Server = Backbone.Model.extend();

window.ServerList = Backbone.Collection.extend({

    model: Server,

    cpuTotal: function(){
        return this.reduce(function(memo, value) { return memo + value.get("cpu") }, 0);
    }

});


var collection = new window.ServerList();
collection.add(new window.Server({teste: "teste", cpu: 5}));
collection.add(new window.Server({teste: "teste1", cpu: 6}));
collection.add(new window.Server({teste: "teste2", cpu: 17}));

alert(collection.cpuTotal())