var contactA = new Backbone.Model({firstName: 'Luke'});
var contactB = new Backbone.Model({firstName: 'John'});
var contactC = new Backbone.Model({firstName: 'Bill'});
var contacts = new Backbone.Collection([contactA,contactB,contactC]);
//below logs ["Luke", "John", "Bill"], not order is same as order added to collection
console.log(contacts.pluck('firstName'));