// **This example introduces two new Model actions (swap and delete), illustrating how such actions can be handled within a Model's View.**
//
// _Working example: [5.html](../5.html)._
//
(function($){
// `Backbone.sync`: Overrides persistence storage with dummy function. This enables use of `Model.destroy()` without raising an error.
Backbone.sync = function(method, model, success, error){
success();
}
var Item = Backbone.Model.extend({
defaults: {
part1: 'hello',
part2: 'world'
}
});
var List = Backbone.Collection.extend({
model: Item
});
var ItemView = Backbone.View.extend({
tagName: 'li', // name of tag to be created
// `ItemView`s now respond to two clickable actions for each `Item`: swap and delete.
events: {
'click span.swap': 'swap',
'click span.delete': 'remove'
},
// `initialize()` now binds model change/removal to the corresponding handlers below.
initialize: function(){
_.bindAll(this, 'render', 'unrender', 'swap', 'remove'); // every function that uses 'this' as the current object should be in here
this.model.bind('change', this.render);
this.model.bind('remove', this.unrender);
},
// `render()` now includes two extra `span`s corresponding to the actions swap and delete.
render: function(){
$(this.el).html(''+this.model.get('part1')+' '+this.model.get('part2')+'[swap][delete]');
return this; // for chainable calls, like .render().el
},
// `unrender()`: Makes Model remove itself from the DOM.
unrender: function(){
$(this.el).remove();
},
// `swap()` will interchange an `Item`'s attributes. When the `.set()` model function is called, the event `change` will be triggered.
swap: function(){
var swapped = {
part1: this.model.get('part2'),
part2: this.model.get('part1')
};
this.model.set(swapped);
},
// `remove()`: We use the method `destroy()` to remove a model from its collection. Normally this would also delete the record from its persistent storage, but we have overridden that (see above).
remove: function(){
this.model.destroy();
}
});
// Because the new features (swap and delete) are intrinsic to each `Item`, there is no need to modify `ListView`.
var ListView = Backbone.View.extend({
el: $('body'), // el attaches to existing element
events: {
'click button#add': 'addItem'
},
initialize: function(){
_.bindAll(this, 'render', 'addItem', 'appendItem'); // 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(){
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: function(){
this.counter++;
var item = new Item();
item.set({
part2: item.get('part2') + this.counter // modify item defaults
});
this.collection.add(item);
},
appendItem: function(item){
var itemView = new ItemView({
model: item
});
$('ul', this.el).append(itemView.render().el);
}
});
var listView = new ListView();
})(jQuery);
//
