Collection

constructor / initializenew Backbone.Collection([models], [options])
When creating a Collection, you may choose to pass in the initial array of models. The collection's comparator may be included as an option. Passing false as the comparator option will prevent sorting. If you define an initialize function, it will be invoked when the collection is created. There are a couple of options that, if provided, are attached to the collection directly: model and comparator.
Pass null for models to create an empty Collection with options.

var tabs = new TabSet([tab1, tab2, tab3]);
var spaces = new Backbone.Collection(null, {
  model: Space
});