// **This example illustrates how to use a Collection of Models to store data, and how to tie changes in those to a View.**
//
// _Working example: [3.html](../3.html)._
// _[Go to Example 4](4.html)_
//
(function($){
// **Item class**: The atomic part of our Model. A model is basically a Javascript object, i.e. key-value pairs, with some helper functions to handle event triggering, persistence, etc.
var Item = Backbone.Model.extend({
defaults: {
part1: 'hello',
part2: 'world'
}
});
// **List class**: A collection of `Item`s. Basically an array of Model objects with some helper functions.
var List = Backbone.Collection.extend({
model: Item
});
var ListView = Backbone.View.extend({
el: $('body'),
events: {
'click button#add': 'addItem'
},
// `initialize()` now instantiates a Collection, and binds its `add` event to own method `appendItem`. (Recall that Backbone doesn't offer a separate Controller for bindings...).
initialize: function(){
_.bindAll(this, 'render', 'addItem', 'appendItem'); // remember: every function that uses 'this' as the current object should be in here
this.collection = new List();
this.collection.bind('add', this.appendItem); // collection event binder
this.counter = 0;
this.render();
},
render: function(){
// Save reference to `this` so it can be accessed from within the scope of the callback below
var self = this;
$(this.el).append("");
$(this.el).append("
");
_(this.collection.models).each(function(item){ // in case collection is not empty
self.appendItem(item);
}, this);
},
// `addItem()` now deals solely with models/collections. View updates are delegated to the `add` event listener `appendItem()` below.
addItem: function(){
this.counter++;
var item = new Item();
item.set({
part2: item.get('part2') + this.counter // modify item defaults
});
this.collection.add(item); // add item to collection; view is updated via event 'add'
},
// `appendItem()` is triggered by the collection event `add`, and handles the visual update.
appendItem: function(item){
$('ul', this.el).append("
"+item.get('part1')+" "+item.get('part2')+"
");
}
});
var listView = new ListView();
})(jQuery);
//
