Edit in JSFiddle

var ContactModel = Backbone.Model.extend();

var contactData = [
    {firstName: 'John',lastName: 'Doe',phone: '1-111-1111'}, 
    {firstName: 'Jane',lastName: 'Doe',phone: '2-222-2222'},
    {firstName: 'Cody',lastName: 'Lindley',phone: '3-333-3333'}
];

var contacts = new Backbone.Collection(contactData,{
    model:ContactModel,
    comparator: 'firstName' //keep models sorted by firstName
});
    
console.log( //logs Cody Jane John, note this is not the order they were added
    contacts.models[0].get('firstName'),
    contacts.models[1].get('firstName'),
    contacts.models[2].get('firstName')
);