forked from jashkenas/backbone
/
index.html
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index.html
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<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="content-type" content="text/html;charset=UTF-8" />
<meta http-equiv="X-UA-Compatible" content="chrome=1">
<title>Backbone.js</title>
<style>
body {
font-size: 14px;
line-height: 22px;
font-family: Helvetica Neue, Helvetica, Arial;
background: #f4f4f4 url(docs/images/background.png);
}
.interface {
font-family: "Lucida Grande", "Lucida Sans Unicode", Helvetica, Arial, sans-serif !important;
}
div#sidebar {
background: #fff;
position: fixed;
top: 0; left: 0; bottom: 0;
width: 200px;
overflow-y: auto;
overflow-x: hidden;
padding: 15px 0 30px 30px;
border-right: 1px solid #ddd;
box-shadow: 0 0 20px #ccc; -webkit-box-shadow: 0 0 20px #ccc; -moz-box-shadow: 0 0 20px #ccc;
}
a.toc_title, a.toc_title:visited {
display: block;
color: black;
font-weight: bold;
margin-top: 15px;
}
div.toc_title:hover {
text-decoration: underline;
}
#sidebar .version {
font-size: 10px;
font-weight: normal;
}
ul.toc_section {
font-size: 11px;
line-height: 14px;
margin: 5px 0 0 0;
padding-left: 0px;
list-style-type: none;
font-family: Lucida Grande;
}
.toc_section li {
cursor: pointer;
margin: 0 0 3px 0;
}
.toc_section li a {
color: black;
}
div.container {
position: relative;
width: 550px;
margin: 40px 0 50px 260px;
}
div.run {
position: absolute;
right: 15px;
width: 26px; height: 18px;
background: url('docs/images/arrows.png') no-repeat -26px 0;
}
div.run:active {
background-position: -51px 0;
}
p, div.container ul {
margin: 20px 0;
width: 550px;
}
p.warning {
font-size: 12px;
line-height: 18px;
font-style: italic;
}
div.container ul {
list-style: circle;
font-size: 12px;
padding-left: 15px;
}
a, a:visited {
color: #444;
text-decoration: none;
}
a:active, a:hover {
color: #000;
text-decoration: underline;
}
a img {
border: 0;
}
h1, h2, h3, h4, h5, h6 {
padding-top: 20px;
}
h2 {
font-size: 20px;
}
b.header {
font-size: 16px;
line-height: 30px;
}
span.alias {
font-size: 14px;
font-style: italic;
margin-left: 20px;
}
table {
margin: 15px 0 0; padding: 0;
}
tr, td {
margin: 0; padding: 0;
}
td {
padding: 0px 15px 5px 0;
}
code, pre, tt {
font-family: Monaco, Consolas, "Lucida Console", monospace;
font-size: 12px;
line-height: 18px;
font-style: normal;
}
tt {
padding: 0px 3px;
background: #fff;
border: 1px solid #ddd;
zoom: 1;
}
code {
margin-left: 20px;
}
pre {
font-size: 12px;
padding: 2px 0 2px 15px;
border: 4px solid #bbb; border-top: 0; border-bottom: 0;
margin: 0px 0 30px;
}
</style>
</head>
<body>
<div id="sidebar" class="interface">
<a class="toc_title" href="#">
Backbone.js <span class="version">(0.3.1)</span>
</a>
<a class="toc_title" href="#Introduction">
Introduction
</a>
<a class="toc_title" href="#Events">
Events
</a>
<ul class="toc_section">
<li>– <a href="#Events-bind">bind</a></li>
<li>– <a href="#Events-unbind">unbind</a></li>
<li>– <a href="#Events-trigger">trigger</a></li>
</ul>
<a class="toc_title" href="#Model">
Model
</a>
<ul class="toc_section">
<li>– <a href="#Model-extend">extend</a></li>
<li>– <a href="#Model-constructor">constructor / initialize</a></li>
<li>– <a href="#Model-get">get</a></li>
<li>– <a href="#Model-set">set</a></li>
<li>– <a href="#Model-unset">unset</a></li>
<li>– <a href="#Model-clear">clear</a></li>
<li>– <a href="#Model-id">id</a></li>
<li>– <a href="#Model-cid">cid</a></li>
<li>– <a href="#Model-attributes">attributes</a></li>
<li>- <a href="#Model-toJSON">toJSON</a></li>
<li>– <a href="#Model-fetch">fetch</a></li>
<li>– <a href="#Model-save">save</a></li>
<li>– <a href="#Model-destroy">destroy</a></li>
<li>– <a href="#Model-validate">validate</a></li>
<li>– <a href="#Model-url">url</a></li>
<li>– <a href="#Model-parse">parse</a></li>
<li>– <a href="#Model-clone">clone</a></li>
<li>– <a href="#Model-isNew">isNew</a></li>
<li>– <a href="#Model-change">change</a></li>
<li>– <a href="#Model-hasChanged">hasChanged</a></li>
<li>– <a href="#Model-changedAttributes">changedAttributes</a></li>
<li>– <a href="#Model-previous">previous</a></li>
<li>– <a href="#Model-previousAttributes">previousAttributes</a></li>
</ul>
<a class="toc_title" href="#Collection">
Collection
</a>
<ul class="toc_section">
<li>– <a href="#Collection-extend">extend</a></li>
<li>– <a href="#Collection-model">model</a></li>
<li>– <a href="#Collection-constructor">constructor / initialize</a></li>
<li>– <a href="#Collection-models">models</a></li>
<li>– <a href="#Collection-toJSON">toJSON</a></li>
<li>– <a href="#Collection-Underscore-Methods"><b>Underscore Methods (25)</b></a></li>
<li>– <a href="#Collection-add">add</a></li>
<li>– <a href="#Collection-remove">remove</a></li>
<li>– <a href="#Collection-get">get</a></li>
<li>– <a href="#Collection-getByCid">getByCid</a></li>
<li>– <a href="#Collection-at">at</a></li>
<li>– <a href="#Collection-length">length</a></li>
<li>– <a href="#Collection-comparator">comparator</a></li>
<li>– <a href="#Collection-sort">sort</a></li>
<li>– <a href="#Collection-pluck">pluck</a></li>
<li>– <a href="#Collection-url">url</a></li>
<li>– <a href="#Collection-parse">parse</a></li>
<li>– <a href="#Collection-fetch">fetch</a></li>
<li>– <a href="#Collection-refresh">refresh</a></li>
<li>– <a href="#Collection-create">create</a></li>
</ul>
<a class="toc_title" href="#Controller">
Controller
</a>
<ul class="toc_section">
<li>– <a href="#Controller-extend">extend</a></li>
<li>– <a href="#Controller-routes">routes</a></li>
<li>– <a href="#Controller-constructor">constructor / initialize</a></li>
<li>– <a href="#Controller-route">route</a></li>
<li>– <a href="#Controller-saveLocation">saveLocation</a></li>
</ul>
<a class="toc_title" href="#History">
History
</a>
<ul class="toc_section">
<li>– <a href="#History-start">start</a></li>
<li>– <a href="#History-saveLocation">saveLocation</a></li>
</ul>
<a class="toc_title" href="#Sync">
Sync
</a>
<ul class="toc_section">
<li>– <a href="#Sync">Backbone.sync</a></li>
<li>– <a href="#Sync-emulateHTTP">Backbone.emulateHTTP</a></li>
<li>– <a href="#Sync-emulateJSON">Backbone.emulateJSON</a></li>
</ul>
<a class="toc_title" href="#View">
View
</a>
<ul class="toc_section">
<li>– <a href="#View-extend">extend</a></li>
<li>– <a href="#View-constructor">constructor / initialize</a></li>
<li>– <a href="#View-el">el</a></li>
<li>– <a href="#View-jQuery">$ (jQuery)</a></li>
<li>– <a href="#View-render">render</a></li>
<li>– <a href="#View-remove">remove</a></li>
<li>– <a href="#View-make">make</a></li>
<li>– <a href="#View-delegateEvents">delegateEvents</a></li>
</ul>
<a class="toc_title" href="#examples">
Examples
</a>
<a class="toc_title" href="#changelog">
Change Log
</a>
</div>
<div class="container">
<p>
<img style="width: 385px; height: 126px;" src="docs/images/backbone.png" alt="Backbone.js" />
</p>
<p>
<a href="http://github.com/documentcloud/backbone/">Backbone</a>
supplies structure to JavaScript-heavy applications by providing <b>models</b> with
key-value binding and custom events, <b>collections</b> with a rich API of enumerable functions,
<b>views</b> with declarative event handling, and connects it all to your
existing application over a RESTful JSON interface.
</p>
<p>
The project is <a href="http://github.com/documentcloud/backbone/">hosted on GitHub</a>,
and the <a href="docs/backbone.html">annotated source code</a> is available,
as well as an online <a href="test/test.html">test suite</a>, and
<a href="examples/todos/index.html">example application</a>.
</p>
<p>
You can report bugs and discuss features on the
<a href="http://github.com/documentcloud/backbone/issues">issues page</a>,
on Freenode in the <tt>#documentcloud</tt> channel,
or send tweets to <a href="http://twitter.com/documentcloud">@documentcloud</a>.
</p>
<p>
<i>
Backbone is an open-source component of
<a href="http://documentcloud.org/">DocumentCloud</a>.
</i>
</p>
<h2 id="downloads">
Downloads & Dependencies
<span style="padding-left: 7px; font-size:11px; font-weight: normal;" class="interface">(Right-click, and use "Save As")</span>
</h2>
<table>
<tr>
<td><a href="backbone.js">Development Version (0.3.1)</a></td>
<td><i>33kb, Uncompressed with Comments</i></td>
</tr>
<tr>
<td><a href="backbone-min.js">Production Version (0.3.1)</a></td>
<td><i>3.7kb, Packed and Gzipped</i></td>
</tr>
</table>
<p>
Backbone's only hard dependency is
<a href="http://documentcloud.github.com/underscore/">Underscore.js</a>.
For RESTful persistence, and DOM manipulation with
<a href="#View">Backbone.View</a>,
it's highly recommended to include <a href="http://jquery.com">jQuery</a>,
and <a href="http://www.json.org/json2.js">json2.js</a>
(both of which you may already have on the page).
</p>
<h2 id="Introduction">Introduction</h2>
<p>
When working on a web application that involves a lot of JavaScript, one
of the first things you learn is to stop tying your data to the DOM. It's all
too easy to create JavaScript applications that end up as tangled piles of
jQuery selectors and callbacks, all trying frantically to keep data in
sync between the HTML UI, your JavaScript logic, and the database on your
server. For rich client-side applications, a more structured approach
is helpful.
</p>
<p>
With Backbone, you represent your data as
<a href="#Model">Models</a>, which can be created, validated, destroyed,
and saved to the server. Whenever a UI action causes an attribute of
a model to change, the model triggers a <i>"change"</i> event; all
the <a href="#View">Views</a> that display the model's data are notified of the
event, causing them to re-render. You don't have to write the glue
code that looks into the DOM to find an element with a specific <i>id</i>,
and update the HTML manually
— when the model changes, the views simply update themselves.
</p>
<p>
<i>How is this different than
<a href="http://www.sproutcore.com/">SproutCore</a> or
<a href="http://cappuccino.org/">Cappuccino</a>?
</i>
</p>
<p>
This question is frequently asked, and all three projects apply general
<a href="http://en.wikipedia.org/wiki/Model–View–Controller">Model-View-Controller</a>
principles to JavaScript applications. However, there isn't much basis
for comparison. SproutCore and Cappuccino provide rich UI widgets, vast
core libraries, and determine the structure of your HTML for you.
Both frameworks measure in the hundreds of kilobytes when packed and
gzipped, and megabytes of JavaScript, CSS, and images when loaded in the browser
— there's a lot of room underneath for libraries of a more moderate scope.
Backbone is a <i>2 kilobyte</i> include that provides
just the core concepts of models, events, collections, views, and persistence.
</p>
<p>
Many of the examples that follow are runnable. Click the <i>play</i> button
to execute them.
</p>
<h2 id="Events">Backbone.Events</h2>
<p>
<b>Events</b> is a module that can be mixed in to any object, giving the
object the ability to bind and trigger custom named events. Events do not
have to be declared before they are bound, and may take passed arguments.
For example:
</p>
<pre class="runnable">
var object = {};
_.extend(object, Backbone.Events);
object.bind("alert", function(msg) {
alert("Triggered " + msg);
});
object.trigger("alert", "an event");
</pre>
<p id="Events-bind">
<b class="header">bind</b><code>object.bind(event, callback)</code>
<br />
Bind a <b>callback</b> function to an object. The callback will be invoked
whenever the <b>event</b> (specified by an arbitrary string identifier) is fired.
If you have a large number of different events on a page, the convention is to use colons to
namespace them: <tt>"poll:start"</tt>, or <tt>"change:selection"</tt>
</p>
<p>
Callbacks bound to the special
<tt>"all"</tt> event will be triggered when any event occurs, and are passed
the name of the event as the first argument. For example, to proxy all events
from one object to another:
</p>
<pre>
proxy.bind("all", function(eventName) {
object.trigger(eventName);
});
</pre>
<p id="Events-unbind">
<b class="header">unbind</b><code>object.unbind([event], [callback])</code>
<br />
Remove a previously-bound <b>callback</b> function from an object. If no
callback is specified, all callbacks for the <b>event</b> will be
removed. If no event is specified, <i>all</i> event callbacks on the object
will be removed.
</p>
<pre>
object.unbind("change", onChange); // Removes just the onChange callback.
object.unbind("change"); // Removes all "change" callbacks.
object.unbind(); // Removes all callbacks on object.
</pre>
<p id="Events-trigger">
<b class="header">trigger</b><code>object.trigger(event, [*args])</code>
<br />
Trigger callbacks for the given <b>event</b>. Subsequent arguments to
<b>trigger</b> will be passed along to the event callbacks.
</p>
<h2 id="Model">Backbone.Model</h2>
<p>
<b>Models</b> are the heart of any JavaScript application, containing
the interactive data as well as a large part of the logic surrounding it:
conversions, validations, computed properties, and access control. You
extend <b>Backbone.Model</b> with your domain-specific methods, and
<b>Model</b> provides a basic set of functionality for managing changes.
</p>
<p>
The following is a contrived example, but it demonstrates defining a model
with a custom method, setting an attribute, and firing an event keyed
to changes in that specific attribute.
After running this code once, <tt>sidebar</tt> will be
available in your browser's console, so you can play around with it.
</p>
<pre class="runnable">
var Sidebar = Backbone.Model.extend({
promptColor: function() {
var cssColor = prompt("Please enter a CSS color:");
this.set({color: cssColor});
}
});
window.sidebar = new Sidebar;
sidebar.bind('change:color', function(model, color) {
$('#sidebar').css({background: color});
});
sidebar.set({color: 'white'});
sidebar.promptColor();
</pre>
<p id="Model-extend">
<b class="header">extend</b><code>Backbone.Model.extend(properties, [classProperties])</code>
<br />
To create a <b>Model</b> class of your own, you extend <b>Backbone.Model</b>
and provide instance <b>properties</b>, as well as optional
<b>classProperties</b> to be attached directly to the constructor function.
</p>
<p>
<b>extend</b> correctly sets up the prototype chain, so subclasses created
with <b>extend</b> can be further extended and subclassed as far as you like.
</p>
<pre>
var Note = Backbone.Model.extend({
initialize: function() { ... },
author: function() { ... },
allowedToEdit: function(account) { ... },
coordinates: function() { ... }
});
</pre>
<p class="warning">
Brief aside on <tt>super</tt>: JavaScript does not provide
a simple way to call super — the function of the same name defined
higher on the prototype chain. If you override a core function like
<tt>set</tt>, or <tt>save</tt>, and you want to invoke the
parent object's implementation, you'll have to explicitly call it, along these lines:
</p>
<pre>
var Note = Backbone.Model.extend({
set: function(attributes, options) {
Backbone.Model.prototype.set.call(this, attributes, options);
...
}
});
</pre>
<p id="Model-constructor">
<b class="header">constructor / initialize</b><code>new Model([attributes])</code>
<br />
When creating an instance of a model, you can pass in the initial values
of the <b>attributes</b>, which will be <a href="#Model-set">set</a> on the
model. If you define an <b>initialize</b> function, it will be invoked when
the model is created.
</p>
<pre>
new Book({
title: "One Thousand and One Nights",
author: "Scheherazade"
});
</pre>
<p id="Model-get">
<b class="header">get</b><code>model.get(attribute)</code>
<br />
Get the current value of an attribute from the model. For example:
<tt>note.get("title")</tt>
</p>
<p id="Model-set">
<b class="header">set</b><code>model.set(attributes, [options])</code>
<br />
Set a hash of attributes (one or many) on the model. If any of the attributes
change the models state, a <tt>"change"</tt> event will be triggered, unless
<tt>{silent: true}</tt> is passed as an option. Change events for specific
attributes are also triggered, and you can bind to those as well, for example:
<tt>change:title</tt>, and <tt>change:content</tt>.
</p>
<pre>
note.set({title: "October 12", content: "Lorem Ipsum Dolor Sit Amet..."});
</pre>
<p>
If the model has a <a href="#Model-validate">validate</a> method,
it will be validated before the attributes are set, no changes will
occur if the validation fails, and <b>set</b> will return <tt>false</tt>.
You may also pass an <tt>error</tt>
callback in the options, which will be invoked instead of triggering an
<tt>"error"</tt> event, should validation fail.
</p>
<p id="Model-unset">
<b class="header">unset</b><code>model.unset(attribute, [options])</code>
<br />
Remove an attribute by deleting it from the internal attributes hash.
Fires a <tt>"change"</tt> event unless <tt>silent</tt> is passed as an option.
</p>
<p id="Model-clear">
<b class="header">clear</b><code>model.clear([options])</code>
<br />
Removes all attributes from the model. Fires a <tt>"change"</tt> event unless
<tt>silent</tt> is passed as an option.
</p>
<p id="Model-id">
<b class="header">id</b><code>model.id</code>
<br />
A special property of models, the <b>id</b> is an arbitrary string
(integer id or UUID). If you set the <b>id</b> in the
attributes hash, it will be copied onto the model as a direct property.
Models can be retrieved by id from collections, and the id is used to generate
model URLs by default.
</p>
<p id="Model-cid">
<b class="header">cid</b><code>model.cid</code>
<br />
A special property of models, the <b>cid</b> or client id is a unique identifier
automatically assigned to all models when they're first created. Client ids
are handy when the model has not yet been saved to the server, and does not
yet have its eventual true <b>id</b>, but already needs to be visible in the UI.
Client ids take the form: <tt>c1, c2, c3 ...</tt>
</p>
<p id="Model-attributes">
<b class="header">attributes</b><code>model.attributes</code>
<br />
The <b>attributes</b> property is the internal hash containing the model's
state. Please use <a href="#Model-set">set</a> to update the attributes instead of modifying
them directly. If you'd like to retrieve and munge a copy of the model's
attributes, use <a href="#Model-toJSON">toJSON</a> instead.
</p>
<p id="Model-toJSON">
<b class="header">toJSON</b><code>model.toJSON()</code>
<br />
Return a copy of the model's <a href="#Model-attributes">attributes</a> for JSON stringification.
This can be used for persistence, serialization, or for augmentation before
being handed off to a view. The name of this method is a bit confusing, as
it doesn't actually return a JSON string — but I'm afraid that it's
the way that the <a href="https://developer.mozilla.org/en/JSON#toJSON()_method">JavaScript API for <b>JSON.stringify</b> works</a>.
</p>
<pre class="runnable">
var artist = new Backbone.Model({
firstName: "Wassily",
lastName: "Kandinsky"
});
artist.set({birthday: "December 16, 1866"});
alert(JSON.stringify(artist));
</pre>
<p id="Model-fetch">
<b class="header">fetch</b><code>model.fetch([options])</code>
<br />
Refreshes the model's state from the server. Useful if the model has never
been populated with data, or if you'd like to ensure that you have the
latest server state. A <tt>"change"</tt> event will be triggered if the
server's state differs from the current attributes. Accepts
<tt>success</tt> and <tt>error</tt> callbacks in the options hash, which
are passed <tt>(model, response)</tt> as arguments.
</p>
<pre>
// Poll every 10 seconds to keep the channel model up-to-date.
setInterval(function() {
channel.fetch();
}, 10000);
</pre>
<p class="warning">
<b>Cautionary Note:</b> When fetching or saving a model, make sure that the model is part of
a collection with a <a href="#Collection-url">url</a> property specified,
or that the model itself has a complete <a href="#Model-url">url</a> function
of its own, so that the request knows where to go.
</p>
<p id="Model-save">
<b class="header">save</b><code>model.save(attributes, [options])</code>
<br />
Save a model to your database (or alternative persistence layer),
by delegating to <a href="#Sync">Backbone.sync</a>. If the model has a <a href="#Model-validate">validate</a>
method, and validation fails, the model will not be saved. If the model
<a href="#Model-isNew">isNew</a>, the save will be a <tt>"create"</tt>
(HTTP <tt>POST</tt>), if the model already
exists on the server, the save will be an <tt>"update"</tt> (HTTP <tt>PUT</tt>). Accepts
<tt>success</tt> and <tt>error</tt> callbacks in the options hash, which
are passed <tt>(model, response)</tt> as arguments. The <tt>error</tt> callback will
also be invoked if the model has a <tt>validate</tt> method, and validation fails.
</p>
<p>
In the following example, notice how because the model has never been
saved previously, our overridden version of <tt>Backbone.sync</tt> receives a <tt>"create"</tt> request.
</p>
<pre class="runnable">
Backbone.sync = function(method, model) {
alert(method + ": " + JSON.stringify(model));
};
var book = new Backbone.Model({
title: "The Rough Riders",
author: "Theodore Roosevelt"
});
book.save();
</pre>
<p id="Model-destroy">
<b class="header">destroy</b><code>model.destroy([options])</code>
<br />
Destroys the model on the server by delegating an HTTP <tt>DELETE</tt>
request to <a href="#Sync">Backbone.sync</a>. Accepts
<tt>success</tt> and <tt>error</tt> callbacks in the options hash.
</p>
<pre>
book.destroy({success: function(model, response) {
...
}});
</pre>
<p id="Model-validate">
<b class="header">validate</b><code>model.validate(attributes)</code>
<br />
This method is left undefined, and you're encouraged to override it with
your custom validation logic, if you have any that can be performed
in JavaScript. <b>validate</b> is called before <tt>set</tt> and
<tt>save</tt>, and is passed the attributes that are about to be updated.
If the model and attributes are valid, don't return anything from <b>validate</b>;
if the attributes are invalid, return an error of your choosing. It
can be as simple as a string error message to be displayed, or a complete
error object that describes the error programmatically. <tt>set</tt> and
<tt>save</tt> will not continue if <b>validate</b> returns an error.
Failed validations trigger an <tt>"error"</tt> event.
</p>
<pre class="runnable">
var Chapter = Backbone.Model.extend({
validate: function(attrs) {
if (attrs.end < attrs.start) {
return "can't end before it starts";
}
}
});
var one = new Chapter({
title : "Chapter One: The Beginning"
});
one.bind("error", function(model, error) {
alert(model.get("title") + " " + error);
});
one.set({
start: 15,
end: 10
});
</pre>
<p>
<tt>"error"</tt> events are useful for providing coarse-grained error
messages at the model or collection level, but if you have a specific view
that can better handle the error, you may override and suppress the event
by passing an <tt>error</tt> callback directly:
</p>
<pre>
account.set({access: "unlimited"}, {
error: function(model, error) {
alert(error);
}
});
</pre>
<p id="Model-url">
<b class="header">url</b><code>model.url()</code>
<br />
Returns the relative URL where the model's resource would be located on
the server. If your models are located somewhere else, override this method
with the correct logic. Generates URLs of the form: <tt>"/[collection]/[id]"</tt>.
</p>
<p>
Delegates to <a href="#Collection-url">Collection#url</a> to generate the
URL, so make sure that you have it defined.
A model with an id of <tt>101</tt>, stored in a
<a href="#Collection">Backbone.Collection</a> with a <tt>url</tt> of <tt>"/notes"</tt>,
would have this URL: <tt>"/notes/101"</tt>
</p>
<p id="Model-parse">
<b class="header">parse</b><code>model.parse(response)</code>
<br />
<b>parse</b> is called whenever a model's data is returned by the
server, in <a href="#Model-fetch">fetch</a>, and <a href="#Model-save">save</a>.
The function is passed the raw <tt>response</tt> object, and should return
the attributes hash to be <a href="#Model-set">set</a> on the model. The
default implementation is a no-op, simply passing through the JSON response.
Override this if you need to work with a preexisting API, or better namespace
your responses.
</p>
<p id="Model-clone">
<b class="header">clone</b><code>model.clone()</code>
<br />
Returns a new instance of the model with identical attributes.
</p>
<p id="Model-isNew">
<b class="header">isNew</b><code>model.isNew()</code>
<br />
Has this model been saved to the server yet? If the model does not yet have
an <tt>id</tt>, it is considered to be new.
</p>
<p id="Model-change">
<b class="header">change</b><code>model.change()</code>
<br />
Manually trigger the <tt>"change"</tt> event.
If you've been passing <tt>{silent: true}</tt> to the <a href="#Model-set">set</a> function in order to
aggregate rapid changes to a model, you'll want to call <tt>model.change()</tt>
when you're all finished.
</p>
<p id="Model-hasChanged">
<b class="header">hasChanged</b><code>model.hasChanged([attribute])</code>
<br />
Has the model changed since the last <tt>"change"</tt> event? If an <b>attribute</b>
is passed, returns <tt>true</tt> if that specific attribute has changed.
</p>
<pre>
book.bind("change", function() {
if (book.hasChanged("title")) {
...
}
});
</pre>
<p id="Model-changedAttributes">
<b class="header">changedAttributes</b><code>model.changedAttributes([attributes])</code>
<br />
Retrieve a hash of only the model's attributes that have changed. Optionally,
an external <b>attributes</b> hash can be passed in, returning
the attributes in that hash which differ from the model. This can be used
to figure out which portions of a view should be updated, or what calls
need to be made to sync the changes to the server.
</p>
<p id="Model-previous">
<b class="header">previous</b><code>model.previous(attribute)</code>
<br />
During a <tt>"change"</tt> event, this method can be used to get the
previous value of a changed attribute.
</p>
<pre class="runnable">
var bill = new Backbone.Model({
name: "Bill Smith"
});
bill.bind("change:name", function(model, name) {
alert("Changed name from " + bill.previous("name") + " to " + name);
});
bill.set({name : "Bill Jones"});
</pre>
<p id="Model-previousAttributes">
<b class="header">previousAttributes</b><code>model.previousAttributes()</code>
<br />
Return a copy of the model's previous attributes. Useful for getting a
diff between versions of a model, or getting back to a valid state after
an error occurs.
</p>
<h2 id="Collection">Backbone.Collection</h2>
<p>
Collections are ordered sets of models. You can to bind <tt>"change"</tt> events
to be notified when any model in the collection has been modified,
listen for <tt>"add"</tt> and <tt>"remove"</tt> events, <tt>fetch</tt>
the collection from the server, and use a full suite of
<a href="#Collection-Underscore-Methods">Underscore.js methods</a>.
</p>
<p>
Collections may also listen for changes to specific attributes in their
models, for example: <tt>Documents.bind("change:selected", ...)</tt>
</p>
<p id="Collection-extend">
<b class="header">extend</b><code>Backbone.Collection.extend(properties, [classProperties])</code>
<br />
To create a <b>Collection</b> class of your own, extend <b>Backbone.Collection</b>,
providing instance <b>properties</b>, as well as optional <b>classProperties</b> to be attached
directly to the collection's constructor function.
</p>
<p id="Collection-model">
<b class="header">model</b><code>collection.model</code>
<br />
Override this property to specify the model class that the collection
contains. If defined, you can pass raw attributes objects (and arrays) to
<a href="#Collection-add">add</a>, <a href="#Collection-create">create</a>,
and <a href="#Collection-refresh">refresh</a>, and the attributes will be
converted into a model of the proper type.
</p>
<pre>
var Library = Backbone.Collection.extend({
model: Book
});
</pre>
<p id="Collection-constructor">
<b class="header">constructor / initialize</b><code>new Collection([models], [options])</code>
<br />
When creating a Collection, you may choose to pass in the initial array of <b>models</b>.
The collection's <a href="#Collection-comparator">comparator</a> function
may be included as an option. If you define an <b>initialize</b> function, it will be
invoked when the collection is created.
</p>
<pre>
var tabs = new TabSet([tab1, tab2, tab3]);
</pre>
<p id="Collection-models">
<b class="header">models</b><code>collection.models</code>
<br />
Raw access to the JavaScript array of models inside of the collection. Usually you'll
want to use <tt>get</tt>, <tt>at</tt>, or the <b>Underscore methods</b>
to access model objects, but occasionally a direct reference to the array
is desired.
</p>
<p id="Collection-toJSON">
<b class="header">toJSON</b><code>collection.toJSON()</code>
<br />
Return an array containing the attributes hash of each model in the
collection. This can be used to serialize and persist the
collection as a whole. The name of this method is a bit confusing, because
it conforms to
<a href="https://developer.mozilla.org/en/JSON#toJSON()_method">JavaScript's JSON API</a>.
</p>
<pre class="runnable">
var collection = new Backbone.Collection([
{name: "Tim", age: 5},
{name: "Ida", age: 26},
{name: "Rob", age: 55}
]);
alert(JSON.stringify(collection));
</pre>
<p id="Collection-Underscore-Methods">
<b class="header">Underscore Methods (25)</b>
<br />
Backbone proxies to <b>Underscore.js</b> to provide 25 iteration functions
on <b>Backbone.Collection</b>. They aren't all documented here, but
you can take a look at the Underscore documentation for the full details…
</p>
<ul>
<li><a href="http://documentcloud.github.com/underscore/#each">forEach (each)</a></li>
<li><a href="http://documentcloud.github.com/underscore/#map">map</a></li>
<li><a href="http://documentcloud.github.com/underscore/#reduce">reduce (foldl, inject)</a></li>
<li><a href="http://documentcloud.github.com/underscore/#reduceRight">reduceRight (foldr)</a></li>
<li><a href="http://documentcloud.github.com/underscore/#detect">find (detect)</a></li>
<li><a href="http://documentcloud.github.com/underscore/#select">filter (select)</a></li>
<li><a href="http://documentcloud.github.com/underscore/#reject">reject</a></li>
<li><a href="http://documentcloud.github.com/underscore/#all">every (all)</a></li>
<li><a href="http://documentcloud.github.com/underscore/#any">some (any)</a></li>
<li><a href="http://documentcloud.github.com/underscore/#include">include</a></li>
<li><a href="http://documentcloud.github.com/underscore/#invoke">invoke</a></li>
<li><a href="http://documentcloud.github.com/underscore/#max">max</a></li>
<li><a href="http://documentcloud.github.com/underscore/#min">min</a></li>
<li><a href="http://documentcloud.github.com/underscore/#sortBy">sortBy</a></li>
<li><a href="http://documentcloud.github.com/underscore/#sortedIndex">sortedIndex</a></li>
<li><a href="http://documentcloud.github.com/underscore/#toArray">toArray</a></li>
<li><a href="http://documentcloud.github.com/underscore/#size">size</a></li>
<li><a href="http://documentcloud.github.com/underscore/#first">first</a></li>
<li><a href="http://documentcloud.github.com/underscore/#rest">rest</a></li>
<li><a href="http://documentcloud.github.com/underscore/#last">last</a></li>
<li><a href="http://documentcloud.github.com/underscore/#without">without</a></li>
<li><a href="http://documentcloud.github.com/underscore/#indexOf">indexOf</a></li>
<li><a href="http://documentcloud.github.com/underscore/#lastIndexOf">lastIndexOf</a></li>
<li><a href="http://documentcloud.github.com/underscore/#isEmpty">isEmpty</a></li>
<li><a href="http://documentcloud.github.com/underscore/#chain">chain</a></li>
</ul>
<pre>
Books.each(function(book) {
book.publish();
});
var titles = Books.map(function(book) {
return book.get("title");
});
var publishedBooks = Books.filter(function(book) {
return book.get("published") === true;
});
var alphabetical = Books.sortBy(function(book) {
return book.author.get("name").toLowerCase();
});
</pre>
<p id="Collection-add">
<b class="header">add</b><code>collection.add(models, [options])</code>