Backbone.js

Backbone.js
Backbone.js
(1.6.0)
GitHub Repository
Annotated Source
Getting Started
Introduction
Models and Views
Collections
API Integration
Rendering
Routing
Events
on
off
trigger
once
listenTo
stopListening
listenToOnce
Catalog of Built-in Events
Model
extend
preinitialize
constructor / initialize
get
set
escape
has
unset
clear
id
idAttribute
cid
cidPrefix
attributes
changed
defaults
toJSON
sync
fetch
destroy
Underscore Methods (9)
validate
validationError
isValid
url
urlRoot
parse
clone
isNew
hasChanged
changedAttributes
previous
previousAttributes
Collection
extend
model
modelId
preinitialize
constructor / initialize
models
toJSON
sync
Underscore Methods (46)
add
remove
reset
set
get
at
push
pop
unshift
shift
slice
length
comparator
sort
pluck
where
findWhere
url
parse
clone
fetch
create
mixin
Router
extend
routes
preinitialize
constructor / initialize
route
navigate
execute
History
start
Sync
Backbone.sync
Backbone.ajax
Backbone.emulateHTTP
Backbone.emulateJSON
View
extend
preinitialize
constructor / initialize
el
$el
setElement
attributes
$ (jQuery)
template
render
remove
events
delegateEvents
undelegateEvents
Utility
Backbone.noConflict
Backbone.$
debugInfo
F.A.Q.
Why Backbone?
More Than One Way To Do It
Nested Models & Collections
Loading Bootstrapped Models
Extending Backbone
Traditional MVC
Binding "this"
Working with Rails
Examples
Todos
DocumentCloud
USA Today
Rdio
Hulu
Quartz
Earth
Vox
Gawker Media
Flow
Gilt Groupe
Enigma
NewsBlur
WordPress.com
Foursquare
Bitbucket
Disqus
Delicious
Khan Academy
IRCCloud
Pitchfork
Spin
ZocDoc
Walmart Mobile
Groupon Now!
Basecamp
Slavery Footprint
Stripe
Airbnb
SoundCloud Mobile
Art.sy
Pandora
Inkling
Code School
CloudApp
SeatGeek
Easel
Jolicloud
Salon.io
TileMill
Blossom
Trello
Tzigla
Change Log
Backbone.js gives structure to web applications
by providing
models
with key-value binding and custom events,
collections
with a rich API of enumerable functions,
views
with declarative event handling, and connects it all to your
existing API over a RESTful JSON interface.
The project is
hosted on GitHub
and the
annotated source code
is available,
as well as an online
test suite
an
example application
list of tutorials
and a
long list of real-world projects
that use Backbone.
Backbone is available for use under the
MIT software license
You can report bugs and discuss features on the
GitHub issues page
or add pages to the
wiki
Backbone is an open-source component of
DocumentCloud
Downloads & Dependencies
(Right-click, and use "Save As")
Development Version (1.6.0)
72kb, Full source, tons of comments
Production Version (1.6.0)
7.9kb, Packed and gzipped
Source Map
Edge Version (master)
Unreleased, use at your own risk
Backbone's only hard dependency is
Underscore.js
( >= 1.8.3)
For RESTful persistence and DOM manipulation with
Backbone.View
include
jQuery
( >= 1.11.0).
(Mimics of the Underscore and jQuery APIs, such as
Lodash
and
Zepto
, will
also tend to work, with varying degrees of compatibility.)
Getting Started
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 often helpful.
With Backbone, you represent your data as
Models
, 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
"change"
event; all
the
Views
that display the model's state can be notified of the
change, so that they are able to respond accordingly, re-rendering themselves with
the new information. In a finished Backbone app, you don't have to write the glue
code that looks into the DOM to find an element with a specific
id
and update the HTML manually
— when the model changes, the views simply update themselves.
Philosophically, Backbone is an attempt to discover the minimal set
of data-structuring (models and collections) and user interface (views
and URLs) primitives that are generally useful when building web applications with
JavaScript. In an ecosystem where overarching, decides-everything-for-you
frameworks are commonplace, and many libraries require your site to be
reorganized to suit their look, feel, and default behavior — Backbone should
continue to be a tool that gives you the
freedom
to design the full
experience of your web application.
If you're new here, and aren't yet quite sure what Backbone is for, start by
browsing the
list of Backbone-based projects
Many of the code examples in this documentation are runnable, because
Backbone is included on this page.
Click the
play
button to execute them.
Models and Views
The single most important thing that Backbone can help you with is keeping
your business logic separate from your user interface. When the two are
entangled, change is hard; when logic doesn't depend on UI, your
interface becomes easier to work with.
Model
Orchestrates data and business logic.
Loads and saves data from the server.
Emits events when data changes.
View
Listens for changes and renders UI.
Handles user input and interactivity.
Sends captured input to the model.
Model
manages an internal table of data attributes, and
triggers
"change"
events when any of its data is modified.
Models handle syncing data with a persistence layer — usually a REST API
with a backing database. Design your models as the atomic reusable objects
containing all of the helpful functions for manipulating their particular
bit of data. Models should be able to be passed around throughout your app,
and used anywhere that bit of data is needed.
View
is an atomic chunk of user interface. It often renders the
data from a specific model, or number of models — but views can
also be data-less chunks of UI that stand alone.
Models should be generally unaware of views. Instead, views listen to
the model
"change"
events, and react or re-render themselves
appropriately.
Collections
Collection
helps you deal with a group of related models, handling
the loading and saving of new models to the server and providing helper
functions for performing aggregations or computations against a list of models.
Aside from their own events, collections also proxy through all of the
events that occur to models within them, allowing you to listen in one place
for any change that might happen to any model in the collection.
API Integration
Backbone is pre-configured to sync with a RESTful API. Simply create a
new Collection with the
url
of your resource endpoint:
var Books = Backbone.Collection.extend({
url: '/books'
});
The
Collection
and
Model
components together form a direct
mapping of REST resources using the following methods:
GET /books/ .... collection.fetch();
POST /books/ .... collection.create();
GET /books/1 ... model.fetch();
PUT /books/1 ... model.save();
DEL /books/1 ... model.destroy();
When fetching raw JSON data from an API, a
Collection
will
automatically populate itself with data formatted as an array, while
Model
will automatically populate itself with data formatted
as an object:
[{"id": 1}] ..... populates a Collection with one model.
{"id": 1} ....... populates a Model with one attribute.
However, it's fairly common to encounter APIs that return data in a
different format than what Backbone expects. For example, consider
fetching a
Collection
from an API that returns the real data
array wrapped in metadata:
"page": 1,
"limit": 10,
"total": 2,
"books": [
{"id": 1, "title": "Pride and Prejudice"},
{"id": 4, "title": "The Great Gatsby"}
In the above example data, a
Collection
should populate using the
"books"
array rather than the root object structure. This
difference is easily reconciled using a
parse
method that
returns (or transforms) the desired portion of API data:
var Books = Backbone.Collection.extend({
url: '/books',
parse: function(data) {
return data.books;
});
View Rendering
Each
View
manages the rendering and user interaction within its own
DOM element. If you're strict about not allowing views to reach outside
of themselves, it helps keep your interface flexible — allowing
views to be rendered in isolation in any place where they might be needed.
Backbone remains unopinionated about the process used to render
View
objects and their subviews into UI: you define how your models get translated
into HTML (or SVG, or Canvas, or something even more exotic).
It could be as prosaic as a simple
Underscore template
, or as fancy as the
React virtual DOM
Some basic approaches to rendering views can be found
in the
Backbone primer
Routing with URLs
In rich web applications, we still want to provide linkable,
bookmarkable, and shareable URLs to meaningful locations within an app.
Use the
Router
to update the browser URL whenever the user
reaches a new "place" in your app that they might want to bookmark or share.
Conversely, the
Router
detects changes to the URL — say,
pressing the "Back" button — and can tell your application exactly where you
are now.
Backbone.Events
Events
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:
var object = {};

_.extend(object, Backbone.Events);

object.on("alert", function(msg) {
alert("Triggered " + msg);
});

object.trigger("alert", "an event");
For example, to make a handy event dispatcher that can coordinate events
among different areas of your application:
var dispatcher = _.clone(Backbone.Events)
on
object.on(event, callback, [context])
Alias: bind
Bind a
callback
function to an object. The callback will be invoked
whenever the
event
is fired.
If you have a large number of different events on a page, the convention is to use colons to
namespace them:
"poll:start"
, or
"change:selection"
The event string may also be a space-delimited list of several events...
book.on("change:title change:author", ...);
Callbacks bound to the special
"all"
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:
proxy.on("all", function(eventName) {
object.trigger(eventName);
});
All Backbone event methods also support an event map syntax, as an alternative
to positional arguments:
book.on({
"change:author": authorPane.update,
"change:title change:subtitle": titleView.update,
"destroy": bookView.remove
});
To supply a
context
value for
this
when the callback is invoked,
pass the optional last argument:
model.on('change', this.render, this)
or
model.on({change: this.render}, this)
off
object.off([event], [callback], [context])
Alias: unbind
Remove a previously-bound
callback
function from an object. If no
context
is specified, all of the versions of the callback with
different contexts will be removed. If no
callback is specified, all callbacks for the
event
will be
removed. If no event is specified, callbacks for
all
events
will be removed.
// Removes just the `onChange` callback.
object.off("change", onChange);

// Removes all "change" callbacks.
object.off("change");

// Removes the `onChange` callback for all events.
object.off(null, onChange);

// Removes all callbacks for `context` for all events.
object.off(null, null, context);

// Removes all callbacks on `object`.
object.off();
Note that calling
model.off()
, for example, will indeed remove
all
events
on the model — including events that Backbone uses for internal bookkeeping.
trigger
object.trigger(event, [*args])
Trigger callbacks for the given
event
, or space-delimited list of events.
Subsequent arguments to
trigger
will be passed along to the
event callbacks.
once
object.once(event, callback, [context])
Just like
on
, but causes the bound callback to fire
only once before being removed. Handy for saying "the next time that X happens, do this".
When multiple events are passed in using the space separated syntax, the event will fire once
for every event you passed in, not once for a combination of all events
listenTo
object.listenTo(other, event, callback)
Tell an
object
to listen to a particular event on an
other
object. The advantage of using this form, instead of
other.on(event,
callback, object)
, is that
listenTo
allows the
object
to keep track of the events, and they can be removed all at once later
on. The
callback
will always be called with
object
as
context.
view.listenTo(model, 'change', view.render);
stopListening
object.stopListening([other], [event], [callback])
Tell an
object
to stop listening to events. Either call
stopListening
with no arguments to have the
object
remove
all of its
registered
callbacks ... or be more
precise by telling it to remove just the events it's listening to on a
specific object, or a specific event, or just a specific callback.
view.stopListening();

view.stopListening(model);
listenToOnce
object.listenToOnce(other, event, callback)
Just like
listenTo
, but causes the bound
callback to fire only once before being removed.
Catalog of Events
Here's the complete list of built-in Backbone events, with arguments.
You're also free to trigger your own events on Models, Collections and
Views as you see fit. The
Backbone
object itself mixes in
Events
and can be used to emit any global events that your application needs.
"add"
(model, collection, options) — when a model is added to a collection.
"remove"
(model, collection, options) — when a model is removed from a collection.
"update"
(collection, options) — single event triggered after any number of models have been added, removed or changed in a collection.
"reset"
(collection, options) — when the collection's entire contents have been
reset
"sort"
(collection, options) — when the collection has been re-sorted.
"change"
(model, options) — when a model's attributes have changed.
"changeId"
(model, previousId, options) — when the model's id has been updated.
"change:[attribute]"
(model, value, options) — when a specific attribute has been updated.
"destroy"
(model, collection, options) — when a model is
destroyed
"request"
(model_or_collection, xhr, options) — when a model or collection has started a request to the server.
"sync"
(model_or_collection, response, options) — when a model or collection has been successfully synced with the server.
"error"
(model_or_collection, xhr, options) — when a model's or collection's request to the server has failed.
"invalid"
(model, error, options) — when a model's
validation
fails on the client.
"route:[name]"
(params) — Fired by the router when a specific route is matched.
"route"
(route, params) — Fired by the router when
any
route has been matched.
"route"
(router, route, params) — Fired by history when
any
route has been matched.
"notfound"
() — Fired by history when
no
route could be matched.
"all"
— this special event fires for
any
triggered event, passing the event name as the first argument followed by all trigger arguments.
Generally speaking, when calling a function that emits an event
model.set
collection.add
, and so on...),
if you'd like to prevent the event from being triggered, you may pass
{silent: true}
as an option. Note that this is
rarely
perhaps even never, a good idea. Passing through a specific flag
in the options for your event callback to look at, and choose to ignore,
will usually work out better.
Backbone.Model
Models
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
Backbone.Model
with your domain-specific methods, and
Model
provides a basic set of functionality for managing changes.
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,
sidebar
will be
available in your browser's console, so you can play around with it.
var Sidebar = Backbone.Model.extend({
promptColor: function() {
var cssColor = prompt("Please enter a CSS color:");
this.set({color: cssColor});
});

window.sidebar = new Sidebar;

sidebar.on('change:color', function(model, color) {
$('#sidebar').css({background: color});
});

sidebar.set({color: 'white'});

sidebar.promptColor();
extend
Backbone.Model.extend(properties, [classProperties])
To create a
Model
class of your own, you extend
Backbone.Model
and provide instance
properties
, as well as optional
classProperties
to be attached directly to the constructor function.
extend
correctly sets up the prototype chain, so subclasses created
with
extend
can be further extended and subclassed as far as you like.
var Note = Backbone.Model.extend({

initialize: function() { ... },

author: function() { ... },

coordinates: function() { ... },

allowedToEdit: function(account) {
return true;

});

var PrivateNote = Note.extend({

allowedToEdit: function(account) {
return account.owns(this);

});
Brief aside on
super
: 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
set
, or
, and you want to invoke the
parent object's implementation, you'll have to explicitly call it, along these lines:
var Note = Backbone.Model.extend({
set: function(attributes, options) {
Backbone.Model.prototype.set.apply(this, arguments);
...
});
preinitialize
new Model([attributes], [options])
For use with models as ES classes. If you define a
preinitialize
method, it will be invoked when the Model is first created, before any
instantiation logic is run for the Model.
class Country extends Backbone.Model {
preinitialize({countryCode}) {
this.name = COUNTRY_NAMES[countryCode];

initialize() { ... }
constructor / initialize
new Model([attributes], [options])
When creating an instance of a model, you can pass in the initial values
of the
attributes
, which will be
set
on the
model. If you define an
initialize
function, it will be invoked when
the model is created.
new Book({
title: "One Thousand and One Nights",
author: "Scheherazade"
});
In rare cases, if you're looking to get fancy,
you may want to override
constructor
, which allows
you to replace the actual constructor function for your model.
var Library = Backbone.Model.extend({
constructor: function() {
this.books = new Books();
Backbone.Model.apply(this, arguments);
},
parse: function(data, options) {
this.books.reset(data.books);
return data.library;
});
If you pass a
{collection: ...}
as the
options
, the model
gains a
collection
property that will be used to indicate which
collection the model belongs to, and is used to help compute the model's
url
. The
model.collection
property is
normally created automatically when you first add a model to a collection.
Note that the reverse is not true, as passing this option to the constructor
will not automatically add the model to the collection. Useful, sometimes.
If
{parse: true}
is passed as an
option
, the
attributes
will first be converted by
parse
before being
set
on the model.
get
model.get(attribute)
Get the current value of an attribute from the model. For example:
note.get("title")
set
model.set(attributes, [options])
Set a hash of attributes (one or many) on the model. If any of the attributes
change the model's state, a
"change"
event will be triggered on the model.
Change events for specific attributes are also triggered, and you can bind
to those as well, for example:
change:title
, and
change:content
You may also pass individual keys and values.
note.set({title: "March 20", content: "In his eyes she eclipses..."});

book.set("title", "A Scandal in Bohemia");
escape
model.escape(attribute)
Similar to
get
, but returns the HTML-escaped version
of a model's attribute. If you're interpolating data from the model into
HTML, using
escape
to retrieve attributes will prevent
XSS
attacks.
var hacker = new Backbone.Model({
name: ""
});

alert(hacker.escape('name'));
has
model.has(attribute)
Returns
true
if the attribute is set to a non-null or non-undefined
value.
if (note.has("title")) {
...
unset
model.unset(attribute, [options])
Remove an attribute by deleting it from the internal attributes hash.
Fires a
"change"
event unless
silent
is passed as an option.
clear
model.clear([options])
Removes all attributes from the model, including the
id
attribute. Fires a
"change"
event unless
silent
is passed as an option.
id
model.id
A special property of models, the
id
is an arbitrary string
(integer id or UUID). If you set the
id
in the
attributes hash, it will be copied onto the model as a direct property.
model.id
should not be manipulated directly,
it should be modified only via
model.set('id', …)
Models can be retrieved by id from collections, and the id is used to generate
model URLs by default.
idAttribute
model.idAttribute
A model's unique identifier is stored under the
id
attribute.
If you're directly communicating with a backend (CouchDB, MongoDB) that uses
a different unique key, you may set a Model's
idAttribute
to
transparently map from that key to
id
If you set
idAttribute
, you may also want to
override
cidPrefix
var Meal = Backbone.Model.extend({
idAttribute: "_id"
});

alert("Dessert will be " + (new Meal).get('dessert'));
Remember that in JavaScript, objects are passed by reference, so if you
include an object as a default value, it will be shared among all instances.
Instead, define
defaults
as a function.
If you set a value for the model’s
idAttribute
, you should define
the defaults as a function that returns a different,
universally
unique id on every invocation. Not doing so would likely prevent an
instance of
Backbone.Collection
from correctly identifying model
hashes and is almost certainly a mistake, unless you never add instances
of the model class to a collection.
toJSON
model.toJSON([options])
Return a shallow copy of the model's
attributes
for JSON stringification. This can be used for persistence,
serialization, or for augmentation before being sent to the server. 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
JavaScript API for
JSON.stringify
works.
var artist = new Backbone.Model({
firstName: "Wassily",
lastName: "Kandinsky"
});

artist.set({birthday: "December 16, 1866"});

alert(JSON.stringify(artist));
sync
model.sync(method, model, [options])
Uses
Backbone.sync
to persist the state of a model to
the server. Can be overridden for custom behavior.
fetch
model.fetch([options])
Merges the model's state with attributes fetched from the server by
delegating to
Backbone.sync
. Returns a
jqXHR
Useful if the model has never
been populated with data, or if you'd like to ensure that you have the
latest server state. Triggers a
"change"
event if the
server's state differs from the current attributes.
fetch
accepts
success
and
error
callbacks in the options hash, which
are both passed
(model, response, options)
as arguments.
// Poll every 10 seconds to keep the channel model up-to-date.
setInterval(function() {
channel.fetch();
}, 10000);
model.save([attributes], [options])
Save a model to your database (or alternative persistence layer),
by delegating to
Backbone.sync
. Returns a
jqXHR
if
validation is successful and
false
otherwise. The
attributes
hash (as in
set
) should contain the attributes
you'd like to change — keys that aren't mentioned won't be altered — but,
complete representation
of the resource will be sent to the server.
As with
set
, you may pass individual keys and values instead of a hash.
If the model has a
validate
method, and validation fails, the model will not be saved. If the model
isNew
, the save will be a
"create"
(HTTP
POST
), if the model already
exists on the server, the save will be an
"update"
(HTTP
PUT
).
If instead, you'd only like the
changed
attributes to be sent to the
server, call
model.save(attrs, {patch: true})
. You'll get an HTTP
PATCH
request to the server with just the passed-in attributes.
Calling
with new attributes will cause a
"change"
event immediately, a
"request"
event as the Ajax request begins to
go to the server, and a
"sync"
event after the server has acknowledged
the successful change. Pass
{wait: true}
if you'd like to wait
for the server before setting the new attributes on the model.
In the following example, notice how our overridden version
of
Backbone.sync
receives a
"create"
request
the first time the model is saved and an
"update"
request the second time.
Backbone.sync = function(method, model) {
alert(method + ": " + JSON.stringify(model));
model.set('id', 1);
};

var book = new Backbone.Model({
title: "The Rough Riders",
author: "Theodore Roosevelt"
});

book.save();

book.save({author: "Teddy"});
accepts
success
and
error
callbacks in the
options hash, which will be passed the arguments
(model, response, options)
If a server-side validation fails, return a non-
200
HTTP response code, along with an error response in text or JSON.
book.save("author", "F.D.R.", {error: function(){ ... }});
destroy
model.destroy([options])
Destroys the model on the server by delegating an HTTP
DELETE
request to
Backbone.sync
. Returns a
jqXHR
object, or
false
if the model
isNew
. Accepts
success
and
error
callbacks in the options hash, which
will be passed
(model, response, options)
Triggers a
"destroy"
event on the model, which will bubble up
through any collections that contain it, a
"request"
event as it
begins the Ajax request to the server, and a
"sync"
event, after
the server has successfully acknowledged the model's deletion. Pass
{wait: true}
if you'd like to wait for the server to respond
before removing the model from the collection.
book.destroy({success: function(model, response) {
...
}});
Underscore Methods (9)
Backbone proxies to
Underscore.js
to provide 9 object functions
on
Backbone.Model
. They aren't all documented here, but
you can take a look at the Underscore documentation for the full details…
keys
values
pairs
invert
pick
omit
chain
isEmpty
user.pick('first_name', 'last_name', 'email');

chapters.keys().join(', ');
validate
model.validate(attributes, options)
This method is left undefined and you're encouraged to override it with
any custom validation logic you have that can be performed in JavaScript.
If the attributes are valid, don't return anything from
validate
if they 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.
By default
checks
validate
before
setting any attributes but you may also tell
set
to validate
the new attributes by passing
{validate: true}
as an option.
The
validate
method receives the model attributes as well as any
options passed to
set
or
, if
validate
returns an error,
does not continue, the model attributes
are not modified on the server, an
"invalid"
event is triggered,
and the
validationError
property is set on the model with the
value returned by this method.
var Chapter = Backbone.Model.extend({
validate: function(attrs, options) {
if (attrs.end < attrs.start) {
return "can't end before it starts";
});

var one = new Chapter({
title : "Chapter One: The Beginning"
});

one.on("invalid", function(model, error) {
alert(model.get("title") + " " + error);
});

one.save({
start: 15,
end: 10
});
"invalid"
events are useful for providing coarse-grained error
messages at the model or collection level.
validationError
model.validationError
The value returned by
validate
during the last failed validation.
isValid
model.isValid(options)
Run
validate
to check the model state.
The
validate
method receives the model attributes as well as any
options passed to
isValid
, if
validate
returns an error
an
"invalid"
event is triggered, and the error is set on the
model in the
validationError
property.
var Chapter = Backbone.Model.extend({
validate: function(attrs, options) {
if (attrs.end < attrs.start) {
return "can't end before it starts";
});

var one = new Chapter({
title : "Chapter One: The Beginning"
});

one.set({
start: 15,
end: 10
});

if (!one.isValid()) {
alert(one.get("title") + " " + one.validationError);
url
model.url()
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:
"[collection.url]/[id]"
by default, but you may override by specifying an explicit
urlRoot
if the model's collection shouldn't be taken into account.
Delegates to
Collection#url
to generate the
URL, so make sure that you have it defined, or a
urlRoot
property, if all models of this class share a common root URL.
A model with an id of
101
, stored in a
Backbone.Collection
with a
url
of
"/documents/7/notes"
would have this URL:
"/documents/7/notes/101"
urlRoot
model.urlRoot or model.urlRoot()
Specify a
urlRoot
if you're using a model
outside
of a collection,
to enable the default
url
function to generate
URLs based on the model id.
"[urlRoot]/id"
Normally, you won't need to define this.
Note that
urlRoot
may also be a function.
var Book = Backbone.Model.extend({urlRoot : '/books'});

var solaris = new Book({id: "1083-lem-solaris"});

alert(solaris.url());
parse
model.parse(response, options)
parse
is called whenever a model's data is returned by the
server, in
fetch
, and
The function is passed the raw
response
object, and should return
the attributes hash to be
set
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.
If you're working with a Rails backend that has a version prior to 3.1,
you'll notice that its default
to_json
implementation includes
a model's attributes under a namespace. To disable this behavior for
seamless Backbone integration, set:
ActiveRecord::Base.include_root_in_json = false
clone
model.clone()
Returns a new instance of the model with identical attributes.
isNew
model.isNew()
Has this model been saved to the server yet? If the model does not yet have
an
id
, it is considered to be new.
hasChanged
model.hasChanged([attribute])
Has the model changed since its last
set
? If an
attribute
is passed, returns
true
if that specific attribute has changed.
Note that this method, and the following change-related ones,
are only useful during the course of a
"change"
event.
book.on("change", function() {
if (book.hasChanged("title")) {
...
});
changedAttributes
model.changedAttributes([attributes])
Retrieve a hash of only the model's attributes that have changed since the last
set
, or
false
if there are none. Optionally, an external
attributes
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.
previous
model.previous(attribute)
During a
"change"
event, this method can be used to get the
previous value of a changed attribute.
var bill = new Backbone.Model({
name: "Bill Smith"
});

bill.on("change:name", function(model, name) {
alert("Changed name from " + bill.previous("name") + " to " + name);
});

bill.set({name : "Bill Jones"});
previousAttributes
model.previousAttributes()
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.
Backbone.Collection
Collections are ordered sets of models. You can bind
"change"
events
to be notified when any model in the collection has been modified,
listen for
"add"
and
"remove"
events,
fetch
the collection from the server, and use a full suite of
Underscore.js methods
Any event that is triggered on a model in a collection will also be
triggered on the collection directly, for convenience.
This allows you to listen for changes to specific attributes in any
model in a collection, for example:
documents.on("change:selected", ...)
extend
Backbone.Collection.extend(properties, [classProperties])
To create a
Collection
class of your own, extend
Backbone.Collection
providing instance
properties
, as well as optional
classProperties
to be attached
directly to the collection's constructor function.
model
collection.model([attrs], [options])
Override this property to specify the model class that the collection contains.
If defined, you can pass raw attributes objects (and arrays) and options to
add
create
and
reset
, and the attributes will be
converted into a model of the proper type using the provided options, if any.
var Library = Backbone.Collection.extend({
model: Book
});
A collection can also contain polymorphic models by overriding this property
with a constructor that returns a model.
var Library = Backbone.Collection.extend({

model: function(attrs, options) {
if (condition) {
return new PublicDocument(attrs, options);
} else {
return new PrivateDocument(attrs, options);

});
modelId
collection.modelId(attrs, idAttribute)
Override this method to return the value the collection will use to
identify a model given its attributes. Useful for combining models from
multiple tables with different
idAttribute
values into a single collection.
By default returns the value of the given
idAttribute
within the
attrs
, or failing that,
id
. If
your collection uses a
model factory
and
the id ranges of those models might collide, you must
override this method.
var Library = Backbone.Collection.extend({
modelId: function(attrs) {
return attrs.type + attrs.id;
});

var library = new Library([
{type: 'dvd', id: 1},
{type: 'vhs', id: 1}
]);

alert(JSON.stringify(collection));
sync
collection.sync(method, collection, [options])
Uses
Backbone.sync
to persist the state of a
collection to the server. Can be overridden for custom behavior.
Underscore Methods (46)
Backbone proxies to
Underscore.js
to provide 46 iteration functions
on
Backbone.Collection
. They aren't all documented here, but
you can take a look at the Underscore documentation for the full details…
Most methods can take an object or string to support model-attribute-style
predicates or a function that receives the model instance as an argument.
forEach (each)
map (collect)
reduce (foldl, inject)
reduceRight (foldr)
find (detect)
findIndex
findLastIndex
filter (select)
reject
every (all)
some (any)
contains (includes)
invoke
max
min
sortBy
groupBy
shuffle
toArray
size
first (head, take)
initial
rest (tail, drop)
last
without
indexOf
lastIndexOf
isEmpty
chain
difference
sample
partition
countBy
indexBy
books.each(function(book) {
book.publish();
});

var titles = books.map("title");

var publishedBooks = books.filter({published: true});

var alphabetical = books.sortBy(function(book) {
return book.author.get("name").toLowerCase();
});

var randomThree = books.sample(3);
add
collection.add(models, [options])
Add a model (or an array of models) to the collection, firing
an
"add"
event for each model, and an
"update"
event afterwards. This is a variant
of
set
with the same options and
return value, but it always adds and never removes. If you're
adding models to the collection that are
already
in the
collection, they'll be ignored, unless you pass
{merge:
true}
, in which case their attributes will be merged into
the corresponding models, firing any
appropriate
"change"
events.
var ships = new Backbone.Collection;

ships.on("add", function(ship) {
alert("Ahoy " + ship.get("name") + "!");
});

ships.add([
{name: "Flying Dutchman"},
{name: "Black Pearl"}
]);
Note that adding the same model (a model with the same
id
) to
a collection more than once
is a no-op.
remove
collection.remove(models, [options])
Remove a model (or an array of models) from the collection, and return
them. Each model can be a Model instance, an
id
string or a JS
object, any value acceptable as the
id
argument of
collection.get
Fires a
"remove"
event for each model, and a single
"update"
event afterwards, unless
{silent: true}
is passed.
The model's index before removal is available to listeners as
options.index
reset
collection.reset([models], [options])
Adding and removing models one at a time is all well and good, but sometimes
you have so many models to change that you'd rather just update the collection
in bulk. Use
reset
to replace a collection with a new list
of models (or attribute hashes), triggering a single
"reset"
event
on completion, and
without
triggering any add or remove events on any models.
Returns the newly-set models.
For convenience, within a
"reset"
event, the list of any
previous models is available as
options.previousModels
Pass
null
for
models
to empty your Collection with
options
Here's an example using
reset
to bootstrap a collection during initial page load,
in a Rails application:

Calling
collection.reset()
without passing any models as arguments
will empty the entire collection.
set
collection.set(models, [options])
The
set
method performs a "smart" update of the
collection with the passed list of models. If a model in the
list isn't yet in the collection it will be added; if the model
is already in the collection its attributes will be merged; and
if the collection contains any models that
aren't
present in the list, they'll be removed. All of
the appropriate
"add"
"remove"
, and
"change"
events
are fired as this happens, with a single
"update"
event
at the end. Returns the touched models in the collection. If
you'd like to customize this behavior, you can change it with
options:
{add: false}
{remove: false}
or
{merge: false}
If a
model
property is defined,
you may also pass raw attributes objects and options, and have
them be vivified as instances of the model using the provided
options. If you set
comparator
, the
collection will automatically sort itself and trigger
"sort"
event, unless you pass
{sort: false}
or use the
{at: index}
option. Pass
{at: index}
to splice the model(s) into the collection at the
specified
index
var vanHalen = new Backbone.Collection([eddie, alex, stone, roth]);

vanHalen.set([eddie, alex, stone, hagar]);

// Fires a "remove" event for roth, and an "add" event for "hagar".
// Updates any of stone, alex, and eddie's attributes that may have
// changed over the years.
get
collection.get(id)
Get a model from a collection, specified by an
id
cid
, or by passing in a
model
var book = library.get(110);
at
collection.at(index)
Get a model from a collection, specified by index. Useful if your collection
is sorted, and if your collection isn't sorted,
at
will still
retrieve models in insertion order. When passed a negative index, it
will retrieve the model from the back of the collection.
push
collection.push(model, [options])
Like
add
, but always adds a model
at the end of the collection and never sorts.
pop
collection.pop([options])
Remove and return the last model from a collection. Takes the same options as
remove
unshift
collection.unshift(model, [options])
Like
add
, but always adds a model
at the beginning of the collection and never sorts.
shift
collection.shift([options])
Remove and return the first model from a collection. Takes the same options as
remove
slice
collection.slice(begin, end)
Return a shallow copy of this collection's models, using the same options as
native
Array#slice
length
collection.length
Like an array, a Collection maintains a
length
property, counting
the number of models it contains.
comparator
collection.comparator
By default there is no
comparator
for a collection.
If you define a comparator, it will be used to sort the collection any
time a model is added.
A comparator can be defined as a
sortBy
(pass a function that takes a single argument),
as a
sort
(pass a comparator function that expects two arguments),
or as a string indicating the attribute to sort by.
"sortBy" comparator functions take a model and return a numeric or string
value by which the model should be ordered relative to others.
"sort" comparator functions take two models, and return
-1
if
the first model should come before the second,
if they are of
the same rank and
if the first model should come after.
Note that Backbone depends on the arity of your comparator function to
determine between the two styles, so be careful if your comparator function
is bound.
Note how even though all of the chapters in this example are added backwards,
they come out in the proper order:
var Chapter = Backbone.Model;
var chapters = new Backbone.Collection;

chapters.comparator = 'page';

chapters.add(new Chapter({page: 9, title: "The End"}));
chapters.add(new Chapter({page: 5, title: "The Middle"}));
chapters.add(new Chapter({page: 1, title: "The Beginning"}));

alert(chapters.pluck('title'));
Collections with a comparator will not automatically re-sort if you
later change model attributes, so you may wish to call
sort
after changing model attributes that would affect the order.
sort
collection.sort([options])
Force a collection to re-sort itself. Note that a collection with a
comparator
will sort itself
automatically whenever a model is added. To disable sorting when adding
a model, pass
{sort: false}
to
add
. Calling
sort
triggers a
"sort"
event on the collection.
pluck
collection.pluck(attribute)
Pluck an attribute from each model in the collection. Equivalent to calling
map
and returning a single attribute from the iterator.
var stooges = new Backbone.Collection([
{name: "Curly"},
{name: "Larry"},
{name: "Moe"}
]);

var names = stooges.pluck("name");

alert(JSON.stringify(names));
where
collection.where(attributes)
Return an array of all the models in a collection that match the
passed
attributes
. Useful for simple cases of
filter
var friends = new Backbone.Collection([
{name: "Athos", job: "Musketeer"},
{name: "Porthos", job: "Musketeer"},
{name: "Aramis", job: "Musketeer"},
{name: "d'Artagnan", job: "Guard"},
]);

var musketeers = friends.where({job: "Musketeer"});

alert(musketeers.length);
findWhere
collection.findWhere(attributes)
Just like
where
, but directly returns only
the first model in the collection that matches the passed
attributes
If no model matches returns
undefined
url
collection.url or collection.url()
Set the
url
property (or function) on a collection to reference
its location on the server. Models within the collection will use
url
to construct URLs of their own.
var Notes = Backbone.Collection.extend({
url: '/notes'
});

// Or, something more sophisticated:

var accounts = new Backbone.Collection;
accounts.url = '/accounts';

accounts.fetch();
The behavior of
fetch
can be customized by using the available
set
options. For example, to fetch a
collection, getting an
"add"
event for every new model, and
"change"
event for every changed existing model, without
removing anything:
collection.fetch({remove: false})
jQuery.ajax
options can also be passed directly as
fetch
options,
so to fetch a specific page of a paginated collection:
Documents.fetch({data: {page: 3}})
Note that
fetch
should not be used to populate collections on
page load — all models needed at load time should already be
bootstrapped
in to place.
fetch
is
intended for lazily-loading models for interfaces that are not needed
immediately: for example, documents with collections of notes that may be
toggled open and closed.
create
collection.create(attributes, [options])
Convenience to create a new instance of a model within a collection.
Equivalent to instantiating a model with a hash of attributes,
saving the model to the server, and adding the model to the set after being
successfully created. Returns the new model. If client-side validation
failed, the model will be unsaved, with validation errors.
In order for this to work, you should set the
model
property of the collection.
The
create
method can accept either an attributes hash and options to be
passed down during model instantiation or an existing, unsaved model object.
Creating a model will cause an immediate
"add"
event to be
triggered on the collection, a
"request"
event as the new model is
sent to the server, as well as a
"sync"
event, once the
server has responded with the successful creation of the model. Pass
{wait: true}
if you'd like to wait for the server before adding the new model to the collection.
var Library = Backbone.Collection.extend({
model: Book
});

var nypl = new Library;

var cart = new Backbone.Collection([
{price: 16, name: 'monopoly'},
{price: 5, name: 'deck of cards'},
{price: 20, name: 'chess'}
]);

var cost = cart.sum('price');
Backbone.Router
Web applications often provide linkable, bookmarkable, shareable URLs for
important locations in the app. Until recently, hash fragments
#page
) were used to provide these permalinks, but with the
arrival of the History API, it's now possible to use standard URLs (
/page
).
Backbone.Router
provides methods for routing client-side pages, and
connecting them to actions and events. For browsers which don't yet support
the History API, the Router handles graceful fallback and transparent
translation to the fragment version of the URL.
During page load, after your application has finished creating all of its routers,
be sure to call
Backbone.history.start()
or
Backbone.history.start({pushState: true})
to route the initial URL.
extend
Backbone.Router.extend(properties, [classProperties])
Get started by creating a custom router class. Define action functions that are
triggered when certain URL fragments are
matched, and provide a
routes
hash
that pairs routes to actions. Note that you'll want to avoid using a
leading slash in your route definitions:
var Workspace = Backbone.Router.extend({

routes: {
"help": "help", // #help
"search/:query": "search", // #search/kiwis
"search/:query/p:page": "search" // #search/kiwis/p7
},

help: function() {
...
},

search: function(query, page) {
...

});
routes
router.routes
The routes hash maps URLs with parameters to functions on your router
(or just direct function definitions, if you prefer),
similar to the
View
's
events hash
Routes can contain parameter parts,
:param
, which match a single URL
component between slashes; and splat parts
*splat
, which can match
any number of URL components. Part of a route can be made optional by
surrounding it in parentheses
(/:optional)
For example, a route of
"search/:query/p:page"
will match
a fragment of
#search/obama/p2
, passing
"obama"
and
"2"
to the action as positional arguments.
A route of
"file/*path"
will match
#file/folder/file.txt
, passing
"folder/file.txt"
to the action.
A route of
"docs/:section(/:subsection)"
will match
#docs/faq
and
#docs/faq/installing
, passing
"faq"
to the action in the first case, and passing
"faq"
and
"installing"
to the action in the second.
A nested optional route of
"docs(/:section)(/:subsection)"
will match
#docs
#docs/faq
, and
#docs/faq/installing
passing
"faq"
to the action in the second case, and passing
"faq"
and
"installing"
to the action in the third.
Trailing slashes are treated as part of the URL, and (correctly) treated
as a unique route when accessed.
docs
and
docs/
will fire
different callbacks. If you can't avoid generating both types of URLs, you
can define a
"docs(/)"
matcher to capture both cases.
When the visitor presses the back button, or enters a URL, and a particular
route is matched, the name of the action will be fired as an
event
, so that other objects can listen to the router,
and be notified. In the following example, visiting
#help/uploading
will fire a
route:help
event from the router.
routes: {
"help/:page": "help",
"download/*path": "download",
"folder/:name": "openFolder",
"folder/:name-:mode": "openFolder"
router.on("route:help", function(page) {
...
});
preinitialize
new Backbone.Router([options])
For use with routers as ES classes. If you define a
preinitialize
method, it will be invoked when the Router is first created and before
any instantiation logic is run for the Router.
class Router extends Backbone.Router {
preinitialize() {
// Override execute method
this.execute = function(callback, args, name) {
if (!loggedIn) {
goToLogin();
return false;
args.push(parseQueryString(args.pop()));
if (callback) callback.apply(this, args);
constructor / initialize
new Router([options])
When creating a new router, you may pass its
routes
hash directly as an option, if you
choose. All
options
will also be passed to your
initialize
function, if defined.
route
router.route(route, name, [callback])
Manually create a route for the router, The
route
argument may
be a
routing string
or regular expression.
Each matching capture from the route or regular expression will be passed as
an argument to the callback. The
name
argument will be triggered as
"route:name"
event whenever the route is matched. If the
callback
argument is omitted
router[name]
will be used
instead. Routes added later may override previously declared routes.
initialize: function(options) {

// Matches #page/10, passing "10"
this.route("page/:number", "page", function(number){ ... });

// Matches /117-a/b/c/open, passing "117-a/b/c" to this.open
this.route(/^(.*?)\/open$/, "open");

open: function(id) { ... }
navigate
router.navigate(fragment, [options])
Whenever you reach a point in your application that you'd like to save
as a URL, call
navigate
in order to update the URL.
If you also wish to call the route function, set the
trigger
option to
true
To update the URL without creating an entry in the browser's history,
set the
replace
option to
true
openPage: function(pageNumber) {
this.document.pages.at(pageNumber).open();
this.navigate("page/" + pageNumber);

# Or ...

app.navigate("help/troubleshooting", {trigger: true});

# Or ...

app.navigate("help/troubleshooting", {trigger: true, replace: true});
execute
router.execute(callback, args, name)
This method is called internally within the router, whenever a route
matches and its corresponding
callback
is about to be executed.
Return
false
from execute to cancel the current transition.
Override it to perform custom parsing or wrapping of your routes, for
example, to parse query strings before handing them to your route
callback, like so:
var Router = Backbone.Router.extend({
execute: function(callback, args, name) {
if (!loggedIn) {
goToLogin();
return false;
args.push(parseQueryString(args.pop()));
if (callback) callback.apply(this, args);
});
Backbone.history
History
serves as a global router (per frame) to handle
hashchange
events or
pushState
, match the appropriate route, and trigger callbacks.
It forwards the
"route"
and
"route[name]"
events of the
matching router, or
"notfound"
when no route in any router
matches the current URL.
You shouldn't ever have to create one of these yourself since
Backbone.history
already contains one.
pushState
support exists on a purely opt-in basis in Backbone.
Older browsers that don't support
pushState
will continue to use
hash-based URL fragments, and if a hash URL is visited by a
pushState
-capable browser, it will be transparently upgraded to
the true URL. Note that using real URLs requires your web server to be
able to correctly render those pages, so back-end changes are required
as well. For example, if you have a route of
/documents/100
your web server must be able to serve that page, if the browser
visits that URL directly. For full search-engine crawlability, it's best to
have the server generate the complete HTML for the page ... but if it's a web
application, just rendering the same content you would have for the root URL,
and filling in the rest with Backbone Views and JavaScript works fine.
start
Backbone.history.start([options])
When all of your
Routers
have been created,
and all of the routes are set up properly, call
Backbone.history.start()
to begin monitoring
hashchange
events, and dispatching routes.
Subsequent calls to
Backbone.history.start()
will throw an error,
and
Backbone.History.started
is a boolean value indicating whether
it has already been called.
To indicate that you'd like to use HTML5
pushState
support in
your application, use
Backbone.history.start({pushState: true})
If you'd like to use
pushState
, but have browsers that don't support
it natively use full page refreshes instead, you can add
{hashChange: false}
to the options.
If your application is not being served from the root url
of your
domain, be sure to tell History where the root really is, as an option:
Backbone.history.start({pushState: true, root: "/public/search/"})
The value provided for
root
will be normalized to include a leading
and trailing slash. When navigating to a route the default behavior is to
exclude the trailing slash from the URL (e.g.,
/public/search?query=...
).
If you prefer to include the trailing slash (e.g.,
/public/search/?query=...
use
Backbone.history.start({trailingSlash: true})
URLs will always contain a leading slash. When root is
URLs will
look like
/?query=...
regardless of the value of
trailingSlash
When called, if a route succeeds with a match for the current URL,
Backbone.history.start()
returns
true
and
the
"route"
and
"route[name]"
events are triggered. If
no defined route matches the current URL, it returns
false
and
"notfound"
is triggered instead.
If the server has already rendered the entire page, and you don't want the
initial route to trigger when starting History, pass
silent: true
Because hash-based history in Internet Explorer relies on an
 , be sure to call start() only after the DOM is ready. $(function(){ new WorkspaceRouter(); new HelpPaneRouter(); Backbone.history.start({pushState: true}); }); Backbone.sync Backbone.sync is the function that Backbone calls every time it attempts to read or save a model to the server. By default, it uses jQuery.ajax to make a RESTful JSON request and returns a jqXHR . You can override it in order to use a different persistence strategy, such as WebSockets, XML transport, or Local Storage. The method signature of Backbone.sync is sync(method, model, [options]) method – the CRUD method ( "create" "read" "update" , or "delete" model – the model to be saved (or collection to be read) options – success and error callbacks, and all other jQuery request options With the default implementation, when Backbone.sync sends up a request to save a model, its attributes will be passed, serialized as JSON, and sent in the HTTP body with content-type application/json . When returning a JSON response, send down the attributes of the model that have been changed by the server, and need to be updated on the client. When responding to a "read" request from a collection Collection#fetch ), send down an array of model attribute objects. Whenever a model or collection begins a sync with the server, a "request" event is emitted. If the request completes successfully you'll get a "sync" event, and an "error" event if not. The sync function may be overridden globally as Backbone.sync or at a finer-grained level, by adding a sync function to a Backbone collection or to an individual model. The default sync handler maps CRUD to REST like so: create → POST /collection read → GET /collection[/id] update → PUT /collection/id patch → PATCH /collection/id delete → DELETE /collection/id As an example, a Rails 4 handler responding to an "update" call from Backbone might look like this: def update account = Account.find params[:id] permitted = params.require(:account).permit(:name, :otherparam) account.update_attributes permitted render :json => account end One more tip for integrating Rails versions prior to 3.1 is to disable the default namespacing for to_json calls on models by setting ActiveRecord::Base.include_root_in_json = false ajax Backbone.ajax = function(request) { ... }; If you want to use a custom AJAX function, or your endpoint doesn't support the jQuery.ajax API and you need to tweak things, you can do so by setting Backbone.ajax emulateHTTP Backbone.emulateHTTP = true If you want to work with a legacy web server that doesn't support Backbone's default REST/HTTP approach, you may choose to turn on Backbone.emulateHTTP Setting this option will fake PUT PATCH and DELETE requests with a HTTP POST , setting the X-HTTP-Method-Override header with the true method. If emulateJSON is also on, the true method will be passed as an additional _method parameter. Backbone.emulateHTTP = true; model.save(); // POST to "/collection/id", with "_method=PUT" + header. emulateJSON Backbone.emulateJSON = true If you're working with a legacy web server that can't handle requests encoded as application/json , setting Backbone.emulateJSON = true; will cause the JSON to be serialized under a model parameter, and the request to be made with a application/x-www-form-urlencoded MIME type, as if from an HTML form. Backbone.View Backbone views are almost more convention than they are code — they don't determine anything about your HTML or CSS for you, and can be used with any JavaScript templating library. The general idea is to organize your interface into logical views, backed by models, each of which can be updated independently when the model changes, without having to redraw the page. Instead of digging into a JSON object, looking up an element in the DOM, and updating the HTML by hand, you can bind your view's render function to the model's "change" event — and now everywhere that model data is displayed in the UI, it is always immediately up to date. extend Backbone.View.extend(properties, [classProperties]) Get started with views by creating a custom view class. You'll want to override the render function, specify your declarative events , and perhaps the tagName className , or id of the View's root element. var DocumentRow = Backbone.View.extend({ tagName: "li", className: "document-row", events: { "click .icon": "open", "click .button.edit": "openEditDialog", "click .button.delete": "destroy" }, initialize: function() { this.listenTo(this.model, "change", this.render); }, render: function() { ... }); Properties like tagName id className el , and events may also be defined as a function, if you want to wait to define them until runtime. preinitialize new View([options]) For use with views as ES classes. If you define a preinitialize method, it will be invoked when the view is first created, before any instantiation logic is run. class Document extends Backbone.View { preinitialize({autoRender}) { this.autoRender = autoRender; initialize() { if (this.autoRender) { this.listenTo(this.model, "change", this.render); constructor / initialize new View([options]) There are several special options that, if passed, will be attached directly to the view: model collection el id className tagName attributes and events If the view defines an initialize function, it will be called when the view is first created. If you'd like to create a view that references an element already in the DOM, pass in the element as an option: new View({el: existingElement}) var doc = documents.first(); new DocumentRow({ model: doc, id: "document-row-" + doc.id }); el view.el All views have a DOM element at all times (the el property), whether they've already been inserted into the page or not. In this fashion, views can be rendered at any time, and inserted into the DOM all at once, in order to get high-performance UI rendering with as few reflows and repaints as possible. this.el can be resolved from a DOM selector string or an Element; otherwise it will be created from the view's tagName className id and attributes properties. If none are set, this.el is an empty div , which is often just fine. An el reference may also be passed in to the view's constructor. var ItemView = Backbone.View.extend({ tagName: 'li' }); var BodyView = Backbone.View.extend({ el: 'body' }); var item = new ItemView(); var body = new BodyView(); alert(item.el + ' ' + body.el); $el view.$el A cached jQuery object for the view's element. A handy reference instead of re-wrapping the DOM element all the time. view.$el.show(); listView.$el.append(itemView.el); setElement view.setElement(element) If you'd like to apply a Backbone view to a different DOM element, use setElement , which will also create the cached $el reference and move the view's delegated events from the old element to the new one. attributes view.attributes A hash of attributes that will be set as HTML DOM element attributes on the view's el (id, class, data-properties, etc.), or a function that returns such a hash. $ (jQuery) view.$(selector) If jQuery is included on the page, each view has a function that runs queries scoped within the view's element. If you use this scoped jQuery function, you don't have to use model ids as part of your query to pull out specific elements in a list, and can rely much more on HTML class attributes. It's equivalent to running: view.$el.find(selector) ui.Chapter = Backbone.View.extend({ serialize : function() { return { title: this.$(".title").text(), start: this.$(".start-page").text(), end: this.$(".end-page").text() }; }); template view.template([data]) While templating for a view isn't a function provided directly by Backbone, it's often a nice convention to define a template function on your views. In this way, when rendering your view, you have convenient access to instance data. For example, using Underscore templates: var LibraryView = Backbone.View.extend({ template: _.template(...) }); render view.render() The default implementation of render is a no-op. Override this function with your code that renders the view template from model data, and updates this.el with the new HTML. A good convention is to return this at the end of render to enable chained calls. var Bookmark = Backbone.View.extend({ template: _.template(...), render: function() { this.$el.html(this.template(this.model.attributes)); return this; }); Backbone is agnostic with respect to your preferred method of HTML templating. Your render function could even munge together an HTML string, or use document.createElement to generate a DOM tree. However, we suggest choosing a nice JavaScript templating library. Mustache.js Haml-js , and Eco are all fine alternatives. Because Underscore.js is already on the page, _.template is available, and is an excellent choice if you prefer simple interpolated-JavaScript style templates. Whatever templating strategy you end up with, it's nice if you never have to put strings of HTML in your JavaScript. At DocumentCloud, we use Jammit in order to package up JavaScript templates stored in /app/views as part of our main core.js asset package. remove view.remove() Removes a view and its el from the DOM, and calls stopListening to remove any bound events that the view has listenTo 'd. events view.events or view.events() The events hash (or method) can be used to specify a set of DOM events that will be bound to methods on your View through delegateEvents Backbone will automatically attach the event listeners at instantiation time, right before invoking initialize var ENTER_KEY = 13; var InputView = Backbone.View.extend({ tagName: 'input', events: { "keydown" : "keyAction", }, render: function() { ... }, keyAction: function(e) { if (e.which === ENTER_KEY) { this.collection.add({text: this.$el.val()}); }); delegateEvents delegateEvents([events]) Uses jQuery's on function to provide declarative callbacks for DOM events within a view. If an events hash is not passed directly, uses this.events as the source. Events are written in the format {"event selector": "callback"} The callback may be either the name of a method on the view, or a direct function body. Omitting the selector causes the event to be bound to the view's root element ( this.el ). By default, delegateEvents is called within the View's constructor for you, so if you have a simple events hash, all of your DOM events will always already be connected, and you will never have to call this function yourself. The events property may also be defined as a function that returns an events hash, to make it easier to programmatically define your events, as well as inherit them from parent views. Using delegateEvents provides a number of advantages over manually using jQuery to bind events to child elements during render . All attached callbacks are bound to the view before being handed off to jQuery, so when the callbacks are invoked, this continues to refer to the view object. When delegateEvents is run again, perhaps with a different events hash, all callbacks are removed and delegated afresh — useful for views which need to behave differently when in different modes. A single-event version of delegateEvents is available as delegate In fact, delegateEvents is simply a multi-event wrapper around delegate A counterpart to undelegateEvents is available as undelegate A view that displays a document in a search result might look something like this: var DocumentView = Backbone.View.extend({ events: { "dblclick" : "open", "click .icon.doc" : "select", "contextmenu .icon.doc" : "showMenu", "click .show_notes" : "toggleNotes", "click .title .lock" : "editAccessLevel", "mouseover .title .date" : "showTooltip" }, render: function() { this.$el.html(this.template(this.model.attributes)); return this; }, open: function() { window.open(this.model.get("viewer_url")); }, select: function() { this.model.set({selected: true}); }, ... }); undelegateEvents undelegateEvents() Removes all of the view's delegated events. Useful if you want to disable or remove a view from the DOM temporarily. Utility Backbone.noConflict var backbone = Backbone.noConflict(); Returns the Backbone object back to its original value. You can use the return value of Backbone.noConflict() to keep a local reference to Backbone. Useful for embedding Backbone on third-party websites, where you don't want to clobber the existing Backbone. var localBackbone = Backbone.noConflict(); var model = localBackbone.Model.extend(...); Backbone.$ Backbone.$ = $; If you have multiple copies of jQuery on the page, or simply want to tell Backbone to use a particular object as its DOM / Ajax library, this is the property for you. Backbone.$ = require('jquery'); debugInfo debugInfo(); In the unfortunate event that you need to submit a bug report , this function makes it easier to provide detailed information about your setup. It prints a JSON object with version information about Backbone and its dependencies through console.debug . It also returns this object in case you want to inspect it in code. debugInfo comes in a separate module that ships with the edge version and releases later than 1.5.0. It is available in UMD format under the same prefix as backbone.js , but with debug-info.js as the file name. It is also experimentally available in ES module format under backbone/modules/  <script src="some-path-or-url/backbone.js"></script> <script src="some-path-or-url/debug-info.js"></script> <script> Backbone.debugInfo(); </script> // CommonJS require('backbone/debug-info.js')(); // ESM import debugInfo from 'backbone/modules/debug-info.js'; debugInfo(); F.A.Q. Why use Backbone, not [other framework X]? If your eye hasn't already been caught by the adaptability and elan on display in the above list of examples , we can get more specific: Backbone.js aims to provide the common foundation that data-rich web applications with ambitious interfaces require — while very deliberately avoiding painting you into a corner by making any decisions that you're better equipped to make yourself. The focus is on supplying you with helpful methods to manipulate and query your data , not on HTML widgets or reinventing the JavaScript object model. Backbone does not force you to use a single template engine. Views can bind to HTML constructed in your favorite way It's smaller. There are fewer kilobytes for your browser or phone to download, and less conceptual surface area. You can read and understand the source in an afternoon. It doesn't depend on stuffing application logic into your HTML. There's no embedded JavaScript, template logic, or binding hookup code in data- or ng- attributes, and no need to invent your own HTML tags. Synchronous events are used as the fundamental building block, not a difficult-to-reason-about run loop, or by constantly polling and traversing your data structures to hunt for changes. And if you want a specific event to be asynchronous and aggregated, no problem Backbone scales well, from embedded widgets to massive apps Backbone is a library, not a framework, and plays well with others. You can embed Backbone widgets in Dojo apps without trouble, or use Backbone models as the data backing for D3 visualizations (to pick two entirely random examples). "Two-way data-binding" is avoided. While it certainly makes for a nifty demo, and works for the most basic CRUD, it doesn't tend to be terribly useful in your real-world app. Sometimes you want to update on every keypress, sometimes on blur, sometimes when the panel is closed, and sometimes when the "save" button is clicked. In almost all cases, simply serializing the form to JSON is faster and easier. All that aside, if your heart is set, go for it There's no built-in performance penalty for choosing to structure your code with Backbone. And if you do want to optimize further, thin models and templates with flexible granularity make it easy to squeeze every last drop of potential performance out of, say, IE8. There's More Than One Way To Do It It's common for folks just getting started to treat the examples listed on this page as some sort of gospel truth. In fact, Backbone.js is intended to be fairly agnostic about many common patterns in client-side code. For example... References between Models and Views can be handled several ways. Some people like to have direct pointers, where views correspond 1:1 with models ( model.view and view.model ). Others prefer to have intermediate "controller" objects that orchestrate the creation and organization of views into a hierarchy. Others still prefer the evented approach, and always fire events instead of calling methods directly. All of these styles work well. Batch operations on Models are common, but often best handled differently depending on your server-side setup. Some folks don't mind making individual Ajax requests. Others create explicit resources for RESTful batch operations: /notes/batch/destroy?ids=1,2,3,4 . Others tunnel REST over JSON, with the creation of "changeset" requests: "create": [array of models to create] "update": [array of models to update] "destroy": [array of model ids to destroy] Feel free to define your own events. Backbone.Events is designed so that you can mix it in to any JavaScript object or prototype. Since you can use any string as an event, it's often handy to bind and trigger your own custom events: model.on("selected:true") or model.on("editing") Render the UI as you see fit. Backbone is agnostic as to whether you use Underscore templates Mustache.js , direct DOM manipulation, server-side rendered snippets of HTML, or jQuery UI in your render function. Sometimes you'll create a view for each model ... sometimes you'll have a view that renders thousands of models at once, in a tight loop. Both can be appropriate in the same app, depending on the quantity of data involved, and the complexity of the UI. Nested Models & Collections It's common to nest collections inside of models with Backbone. For example, consider a Mailbox model that contains many Message models. One nice pattern for handling this is have a this.messages collection for each mailbox, enabling the lazy-loading of messages, when the mailbox is first opened ... perhaps with MessageList views listening for "add" and "remove" events. var Mailbox = Backbone.Model.extend({ initialize: function() { this.messages = new Messages; this.messages.url = '/mailbox/' + this.id + '/messages'; this.messages.on("reset", this.updateCounts); }, ... }); var inbox = new Mailbox; // And then, when the Inbox is opened: inbox.messages.fetch({reset: true}); If you're looking for something more opinionated, there are a number of Backbone plugins that add sophisticated associations among models, available on the wiki Backbone doesn't include direct support for nested models and collections or "has many" associations because there are a number of good patterns for modeling structured data on the client side, and Backbone should provide the foundation for implementing any of them. You may want to… Mirror an SQL database's structure, or the structure of a NoSQL database. Use models with arrays of "foreign key" ids, and join to top level collections (a-la tables). For associations that are numerous, use a range of ids instead of an explicit list. Avoid ids, and use direct references, creating a partial object graph representing your data set. Lazily load joined models from the server, or lazily deserialize nested models from JSON documents. Loading Bootstrapped Models When your app first loads, it's common to have a set of initial models that you know you're going to need, in order to render the page. Instead of firing an extra AJAX request to fetch them, a nicer pattern is to have their data already bootstrapped into the page. You can then use reset to populate your collections with the initial data. At DocumentCloud, in the ERB template for the workspace, we do something along these lines: <script> var accounts = new Backbone.Collection; accounts.reset(<%= @accounts.to_json %>); var projects = new Backbone.Collection; projects.reset(<%= @projects.to_json(:collaborators => true) %>); </script> You have to escape </ within the JSON string, to prevent JavaScript injection attacks. Extending Backbone Many JavaScript libraries are meant to be insular and self-enclosed, where you interact with them by calling their public API, but never peek inside at the guts. Backbone.js is not that kind of library. Because it serves as a foundation for your application, you're meant to extend and enhance it in the ways you see fit — the entire source code is annotated to make this easier for you. You'll find that there's very little there apart from core functions, and most of those can be overridden or augmented should you find the need. If you catch yourself adding methods to Backbone.Model.prototype or creating your own base subclass, don't worry — that's how things are supposed to work. How does Backbone relate to "traditional" MVC? Different implementations of the Model-View-Controller pattern tend to disagree about the definition of a controller. If it helps any, in Backbone, the View class can also be thought of as a kind of controller, dispatching events that originate from the UI, with the HTML template serving as the true view. We call it a View because it represents a logical chunk of UI, responsible for the contents of a single DOM element. Comparing the overall structure of Backbone to a server-side MVC framework like Rails , the pieces line up like so: Backbone.Model – Like a Rails model minus the class methods. Wraps a row of data in business logic. Backbone.Collection – A group of models on the client-side, with sorting/filtering/aggregation logic. Backbone.Router – Rails routes.rb + Rails controller actions. Maps URLs to functions. Backbone.View – A logical, re-usable piece of UI. Often, but not always, associated with a model. Client-side Templates – Rails .html.erb views, rendering a chunk of HTML. Binding "this" Perhaps the single most common JavaScript "gotcha" is the fact that when you pass a function as a callback, its value for this is lost. When dealing with events and callbacks in Backbone, you'll often find it useful to rely on listenTo or the optional context argument that many of Underscore and Backbone's methods use to specify the this that will be used when the callback is later invoked. (See _.each _.map , and object.on , to name a few). View events are automatically bound to the view's context for you. You may also find it helpful to use _.bind and _.bindAll from Underscore.js. var MessageList = Backbone.View.extend({ initialize: function() { var messages = this.collection; messages.on("reset", this.render, this); messages.on("add", this.addMessage, this); messages.on("remove", this.removeMessage, this); messsages.each(this.addMessage, this); }); // Later, in the app... Inbox.messages.add(newMessage); Working with Rails Backbone.js was originally extracted from a Rails application ; getting your client-side (Backbone) Models to sync correctly with your server-side (Rails) Models is painless, but there are still a few things to be aware of. By default, Rails versions prior to 3.1 add an extra layer of wrapping around the JSON representation of models. You can disable this wrapping by setting: ActiveRecord::Base.include_root_in_json = false ... in your configuration. Otherwise, override parse to pull model attributes out of the wrapper. Similarly, Backbone PUTs and POSTs direct JSON representations of models, where by default Rails expects namespaced attributes. You can have your controllers filter attributes directly from params , or you can override toJSON in Backbone to add the extra wrapping Rails expects. Examples The list of examples that follows, while long, is not exhaustive — nor in any way current. If you've worked on an app that uses Backbone, please add it to the wiki page of Backbone apps Jérôme Gravel-Niquet has contributed a Todo List application that is bundled in the repository as Backbone example. If you're wondering where to get started with Backbone in general, take a moment to read through the annotated source . The app uses a LocalStorage adapter to transparently save all of your todos within your browser, instead of sending them to a server. Jérôme also has a version hosted at localtodos.com DocumentCloud The DocumentCloud workspace is built on Backbone.js, with Documents Projects Notes , and Accounts all as Backbone models and collections. If you're interested in history — both Underscore.js and Backbone.js were originally extracted from the DocumentCloud codebase, and packaged into standalone JS libraries. USA Today USA Today takes advantage of the modularity of Backbone's data/model lifecycle — which makes it simple to create, inherit, isolate, and link application objects — to keep the codebase both manageable and efficient. The new website also makes heavy use of the Backbone Router to control the page for both pushState-capable and legacy browsers. Finally, the team took advantage of Backbone's Event module to create a PubSub API that allows third parties and analytics packages to hook into the heart of the app. Rdio New Rdio was developed from the ground up with a component based framework based on Backbone.js. Every component on the screen is dynamically loaded and rendered, with data provided by the Rdio API . When changes are pushed, every component can update itself without reloading the page or interrupting the user's music. All of this relies on Backbone's views and models, and all URL routing is handled by Backbone's Router. When data changes are signaled in realtime, Backbone's Events notify the interested components in the data changes. Backbone forms the core of the new, dynamic, realtime Rdio web and desktop applications. Hulu Hulu used Backbone.js to build its next generation online video experience. With Backbone as a foundation, the web interface was rewritten from scratch so that all page content can be loaded dynamically with smooth transitions as you navigate. Backbone makes it easy to move through the app quickly without the reloading of scripts and embedded videos, while also offering models and collections for additional data manipulation support. Quartz Quartz sees itself as a digitally native news outlet for the new global economy. Because Quartz believes in the future of open, cross-platform web applications, they selected Backbone and Underscore to fetch, sort, store, and display content from a custom WordPress API. Although qz.com uses responsive design for phone, tablet, and desktop browsers, it also takes advantage of Backbone events and views to render device-specific templates in some cases. Earth Earth.nullschool.net displays real-time weather conditions on an interactive animated globe, and Backbone provides the foundation upon which all of the site's components are built. Despite the presence of several other JavaScript libraries, Backbone's non-opinionated design made it effortless to mix-in the Events functionality used for distributing state changes throughout the page. When the decision was made to switch to Backbone, large blocks of custom logic simply disappeared. Vox Vox Media, the publisher of SB Nation The Verge Polygon Eater Racked Curbed , and Vox.com , uses Backbone throughout Chorus its home-grown publishing platform. Backbone powers the liveblogging platform and commenting system used across all Vox Media properties; Coverage, an internal editorial coordination tool; SB Nation Live a live event coverage and chat tool; and Vox Cards Vox.com's highlighter-and-index-card inspired app for providing context about the news. Gawker Media Kinja is Gawker Media's publishing platform designed to create great stories by breaking down the lines between the traditional roles of content creators and consumers. Everyone — editors, readers, marketers — have access to the same tools to engage in passionate discussion and pursue the truth of the story. Sharing, recommending, and following within the Kinja ecosystem allows for improved information discovery across all the sites. Kinja is the platform behind Gawker Gizmodo Lifehacker io9 and other Gawker Media blogs. Backbone.js underlies the front-end application code that powers everything from user authentication to post authoring, commenting, and even serving ads. The JavaScript stack includes Underscore.js and jQuery , with some plugins, all loaded with RequireJS . Closure templates are shared between the Play! Framework based Scala application and Backbone views, and the responsive layout is done with the Foundation framework using SASS Flow MetaLab used Backbone.js to create Flow , a task management app for teams. The workspace relies on Backbone.js to construct task views, activities, accounts, folders, projects, and tags. You can see the internals under window.Flow Gilt Groupe Gilt Groupe uses Backbone.js to build multiple applications across their family of sites. Gilt's mobile website uses Backbone and Zepto.js to create a blazing-fast shopping experience for users on-the-go, while Gilt Live combines Backbone with WebSockets to display the items that customers are buying in real-time. Gilt's search functionality also uses Backbone to filter and sort products efficiently by moving those actions to the client-side. Enigma Enigma is a portal amassing the largest collection of public data produced by governments, universities, companies, and organizations. Enigma uses Backbone Models and Collections to represent complex data structures; and Backbone's Router gives Enigma users unique URLs for application states, allowing them to navigate quickly through the site while maintaining the ability to bookmark pages and navigate forward and backward through their session. NewsBlur NewsBlur is an RSS feed reader and social news network with a fast and responsive UI that feels like a native desktop app. Backbone.js was selected for a major rewrite and transition from spaghetti code because of its powerful yet simple feature set, easy integration, and large community. If you want to poke around under the hood, NewsBlur is also entirely open-source WordPress.com WordPress.com is the software-as-a-service version of WordPress . It uses Backbone.js Models, Collections, and Views in its Notifications system . Backbone.js was selected because it was easy to fit into the structure of the application, not the other way around. Automattic (the company behind WordPress.com) is integrating Backbone.js into the Stats tab and other features throughout the homepage. Foursquare Foursquare is a fun little startup that helps you meet up with friends, discover new places, and save money. Backbone Models are heavily used in the core JavaScript API layer and Views power many popular features like the homepage map and lists Bitbucket Bitbucket is a free source code hosting service for Git and Mercurial. Through its models and collections, Backbone.js has proved valuable in supporting Bitbucket's REST API , as well as newer components such as in-line code comments and approvals for pull requests. Mustache templates provide server and client-side rendering, while a custom Google Closure inspired life-cycle for widgets allows Bitbucket to decorate existing DOM trees and insert new ones. Disqus Disqus chose Backbone.js to power the latest version of their commenting widget. Backbone’s small footprint and easy extensibility made it the right choice for Disqus’ distributed web application, which is hosted entirely inside an iframe and served on thousands of large web properties, including IGN, Wired, CNN, MLB, and more. Delicious Delicious is a social bookmarking platform making it easy to save, sort, and store bookmarks from across the web. Delicious uses Chaplin.js Backbone.js and AppCache to build a full-featured MVC web app. The use of Backbone helped the website and mobile apps share a single API service, and the reuse of the model tier made it significantly easier to share code during the recent Delicious redesign. Khan Academy Khan Academy is on a mission to provide a free world-class education to anyone anywhere. With thousands of videos, hundreds of JavaScript-driven exercises, and big plans for the future, Khan Academy uses Backbone to keep frontend code modular and organized. User profiles and goal setting are implemented with Backbone, jQuery and Handlebars , and most new feature work is being pushed to the client side, greatly increasing the quality of the API IRCCloud IRCCloud is an always-connected IRC client that you use in your browser — often leaving it open all day in a tab. The sleek web interface communicates with an Erlang backend via websockets and the IRCCloud API It makes heavy use of Backbone.js events, models, views and routing to keep your IRC conversations flowing in real time. Pitchfork Pitchfork uses Backbone.js to power its site-wide audio player, Pitchfork.tv location routing, a write-thru page fragment cache, and more. Backbone.js (and Underscore.js ) helps the team create clean and modular components, move very quickly, and focus on the site, not the spaghetti. Spin Spin pulls in the latest news stories from their internal API onto their site using Backbone models and collections, and a custom sync method. Because the music should never stop playing, even as you click through to different "pages", Spin uses a Backbone router for navigation within the site. ZocDoc ZocDoc helps patients find local, in-network doctors and dentists, see their real-time availability, and instantly book appointments. On the public side, the webapp uses Backbone.js to handle client-side state and rendering in search pages and doctor profiles In addition, the new version of the doctor-facing part of the website is a large single-page application that benefits from Backbone's structure and modularity. ZocDoc's Backbone classes are tested with Jasmine , and delivered to the end user with Cassette Walmart Mobile Walmart used Backbone.js to create the new version of their mobile web application and created two new frameworks in the process. Thorax provides mixins, inheritable events, as well as model and collection view bindings that integrate directly with Handlebars templates. Lumbar allows the application to be split into modules which can be loaded on demand, and creates platform specific builds for the portions of the web application that are embedded in Walmart's native Android and iOS applications. Groupon Now! Groupon Now! helps you find local deals that you can buy and use right now. When first developing the product, the team decided it would be AJAX heavy with smooth transitions between sections instead of full refreshes, but still needed to be fully linkable and shareable. Despite never having used Backbone before, the learning curve was incredibly quick — a prototype was hacked out in an afternoon, and the team was able to ship the product in two weeks. Because the source is minimal and understandable, it was easy to add several Backbone extensions for Groupon Now!: changing the router to handle URLs with querystring parameters, and adding a simple in-memory store for caching repeated requests for the same data. Basecamp 37Signals chose Backbone.js to create the calendar feature of its popular project management software Basecamp The Basecamp Calendar uses Backbone.js models and views in conjunction with the Eco templating system to present a polished, highly interactive group scheduling interface. Slavery Footprint Slavery Footprint allows consumers to visualize how their consumption habits are connected to modern-day slavery and provides them with an opportunity to have a deeper conversation with the companies that manufacture the goods they purchased. Based in Oakland, California, the Slavery Footprint team works to engage individuals, groups, and businesses to build awareness for and create deployable action against forced labor, human trafficking, and modern-day slavery through online tools, as well as off-line community education and mobilization programs. Stripe Stripe provides an API for accepting credit cards on the web. Stripe's management interface was recently rewritten from scratch in CoffeeScript using Backbone.js as the primary framework, Eco for templates, Sass for stylesheets, and Stitch to package everything together as CommonJS modules. The new app uses Stripe's API directly for the majority of its actions; Backbone.js models made it simple to map client-side models to their corresponding RESTful resources. Airbnb Airbnb uses Backbone in many of its products. It started with Airbnb Mobile Web (built in six weeks by a team of three) and has since grown to Wish Lists Match , Communities, Payments, and Internal Tools. SoundCloud Mobile SoundCloud is the leading sound sharing platform on the internet, and Backbone.js provides the foundation for SoundCloud Mobile . The project uses the public SoundCloud API as a data source (channeled through a nginx proxy), jQuery templates for the rendering, Qunit and PhantomJS for the testing suite. The JS code, templates and CSS are built for the production deployment with various Node.js tools like ready.js Jake jsdom The Backbone.History was modified to support the HTML5 history.pushState Backbone.sync was extended with an additional SessionStorage based cache layer. Art.sy Art.sy is a place to discover art you'll love. Art.sy is built on Rails, using Grape to serve a robust JSON API . The main site is a single page app written in CoffeeScript and uses Backbone to provide structure around this API. An admin panel and partner CMS have also been extracted into their own API-consuming Backbone projects. Pandora When Pandora redesigned their site in HTML5, they chose Backbone.js to help manage the user interface and interactions. For example, there's a model that represents the "currently playing track", and multiple views that automatically update when the current track changes. The station list is a collection, so that when stations are added or changed, the UI stays up to date. Inkling Inkling is a cross-platform way to publish interactive learning content. Inkling for Web uses Backbone.js to make hundreds of complex books — from student textbooks to travel guides and programming manuals — engaging and accessible on the web. Inkling supports WebGL-enabled 3D graphics, interactive assessments, social sharing, and a system for running practice code right in the book, all within a single page Backbone-driven app. Early on, the team decided to keep the site lightweight by using only Backbone.js and raw JavaScript. The result? Complete source code weighing in at a mere 350kb with feature-parity across the iPad, iPhone and web clients. Give it a try with this excerpt from JavaScript: The Definitive Guide Code School Code School courses teach people about various programming topics like CoffeeScript , CSS, Ruby on Rails, and more. The new Code School course challenge page is built from the ground up on Backbone.js, using everything it has to offer: the router, collections, models, and complex event handling. Before, the page was a mess of jQuery DOM manipulation and manual Ajax calls. Backbone.js helped introduce a new way to think about developing an organized front-end application in JavaScript. CloudApp CloudApp is simple file and link sharing for the Mac. Backbone.js powers the web tools which consume the documented API to manage Drops. Data is either pulled manually or pushed by Pusher and fed to Mustache templates for rendering. Check out the annotated source code to see the magic. SeatGeek SeatGeek 's stadium ticket maps were originally developed with Prototype.js . Moving to Backbone.js and jQuery helped organize a lot of the UI code, and the increased structure has made adding features a lot easier. SeatGeek is also in the process of building a mobile interface that will be Backbone.js from top to bottom. Easel Easel is an in-browser, high fidelity web design tool that integrates with your design and development process. The Easel team uses CoffeeScript, Underscore.js and Backbone.js for their rich visual editor as well as other management functions throughout the site. The structure of Backbone allowed the team to break the complex problem of building a visual editor into manageable components and still move quickly. Jolicloud Jolicloud is an open and independent platform and operating system that provides music playback, video streaming, photo browsing and document editing — transforming low cost computers into beautiful cloud devices. The new Jolicloud HTML5 app was built from the ground up using Backbone and talks to the Jolicloud Platform , which is based on Node.js. Jolicloud works offline using the HTML5 AppCache, extends Backbone.sync to store data in IndexedDB or localStorage, and communicates with the Joli OS via WebSockets. Salon.io Salon.io provides a space where photographers, artists and designers freely arrange their visual art on virtual walls. Salon.io runs on Rails , but does not use much of the traditional stack, as the entire frontend is designed as a single page web app, using Backbone.js, Brunch and CoffeeScript TileMill Our fellow Knight Foundation News Challenge winners, MapBox , created an open-source map design studio with Backbone.js: TileMill TileMill lets you manage map layers based on shapefiles and rasters, and edit their appearance directly in the browser with the Carto styling language Note that the gorgeous MapBox homepage is also a Backbone.js app. Blossom Blossom is a lightweight project management tool for lean teams. Backbone.js is heavily used in combination with CoffeeScript to provide a smooth interaction experience. The app is packaged with Brunch The RESTful backend is built with Flask on Google App Engine. Trello Trello is a collaboration tool that organizes your projects into boards. A Trello board holds many lists of cards, which can contain checklists, files and conversations, and may be voted on and organized with labels. Updates on the board happen in real time. The site was built ground up using Backbone.js for all the models, views, and routes. Tzigla Cristi Balan and Irina Dumitrascu created Tzigla , a collaborative drawing application where artists make tiles that connect to each other to create surreal drawings Backbone models help organize the code, routers provide bookmarkable deep links and the views are rendered with haml.js and Zepto Tzigla is written in Ruby ( Rails ) on the backend, and CoffeeScript on the frontend, with Jammit prepackaging the static assets. Change Log 1.6.0 Feb. 5, 2024 Diff Docs Added a notfound event to Backbone.history for when no router matches the current URL. Added the debugInfo function to make bug reports easier. Fixed a corner case where a collection would forward error events twice if the model was first added through the create method with wait: true Added issue templates and other documentation improvements. 1.5.0 Jul. 28, 2023 Diff Docs Added a trailingSlash option to the Backbone.history.start method. When this option is true , the trailing slash of the root is always retained in the route, even if the path segment of the current URL is empty. Fixed a bug that caused collection add events to include an irrelevant options.index if other models were removed during the same call to Collection.set Fixed a corner case where a collection would not forward the error event if Collection.create was invoked with {wait: true} Adapted CoffeeScript Model test to CoffeeScript version 2. Added a security policy and a code of conduct. Added a .editorconfig to the project root in order to promote consistent whitespace handling across editors. Many clarifications, corrections and refinements to the documentation, as well as some code comments. 1.4.1 Feb. 26, 2022 Diff Docs Improved support for polymorphic collections in which two or more model types might have different idAttribute s. Collection.modelId() overrides can now exploit the fact that internal methods pass the idAttribute as a second argument to modelId Fixed a temporary inconsistency in a collection's internal administration during model change events. Models (and by extension, collections) now emit a specialized changeId event when the id changes. Fixed an issue where an ES6 class or object method could not be used as the model for a collection due to the lack of a prototype Restored continuous integration using GitHub Actions and cross-browser testing using Sauce Labs. Several improvements to the online documentation. Due to upgraded development tools, the annotated sources of the example code as well as the sourcemap of the minified bundle have changed filenames. Aliases and redirects in the old locations are kept for backwards compatibility. 1.4.0 Feb. 19, 2019 Diff Docs Collections now support the Javascript Iterator Protocol! listenTo uses the listened object's public on method. This helps maintain interoperability between Backbone and other event libraries (including Node.js). Added support for setting instance properties before the constructor in ES2015 classes with a preinitialize method. Collection.get now checks if obj is a Model to allow retrieving models with an `attributes` key. Fixed several issues with Router's URL hashing and parsing. 1.3.3 Apr. 5, 2016 Diff Docs Added findIndex and findLastIndex Underscore methods to Collection Added options.changes to Collection "update" event which includes added, merged, and removed models. Added support for Collection#mixin and Model#mixin Ensured Collection#reduce and Collection#reduceRight work without an initial accumulator value. Ensured Collection#_removeModels always returns an array. Fixed a bug where Events.once with object syntax failed to bind context. Fixed Collection#_onModelEvent regression where triggering a change event without a model would error. Fixed Collection#set regression when parse returns a falsy value. Fixed Model#id regression where id would be unintentionally undefined Fixed _removeModels regression which could cause an infinite loop under certain conditions. Removed component package support. Note that 1.3.3 fixes several bugs in versions 1.3.0 to 1.3.2. Please upgrade immediately if you are on one of those versions. 1.2.3 Sept. 3, 2015 Diff Docs Fixed a minor regression in 1.2.2 that would cause an error when adding a model to a collection at an out of bounds index. 1.2.2 Aug. 19, 2015 Diff Docs Collection methods find filter reject every some , and partition can now take a model-attributes-style predicate: this.collection.reject({user: 'guybrush'}) Backbone Events once again supports multiple-event maps obj.on({'error change': action}) ). This was a previously undocumented feature inadvertently removed in 1.2.0. Added Collection#includes as an alias of Collection#contains and as a replacement for Collection#include in Underscore.js >= 1.8. 1.2.1 Jun. 4, 2015 Diff Docs Collection#add now avoids trying to parse a model instance when passed parse: false Bug fix in Collection#remove . The removed models are now actually returned. Model#fetch no longer parses the response when passing parse: false Bug fix for iframe-based History when used with JSDOM. Bug fix where Collection#invoke was not taking additional arguments. When using on with an event map, you can now pass the context as the second argument. This was a previously undocumented feature inadvertently removed in 1.2.0. 1.2.0 May 13, 2015 Diff Docs Added new hooks to Views to allow them to work without jQuery. See the wiki page for more info. As a neat side effect, Backbone.History no longer uses jQuery's event methods for pushState and hashChange listeners. We're native all the way. Also on the subject of jQuery, if you're using Backbone with CommonJS (node, browserify, webpack) Backbone will automatically try to load jQuery for you. Views now always delegate their events in setElement You can no longer modify the events hash or your view's el property in initialize Added an "update" event that triggers after any amount of models are added or removed from a collection. Handy to re-render lists of things without debouncing. Collection#at can take a negative index. Added modelId to Collection for generating unique ids on polymorphic collections. Handy for cases when your model ids would otherwise collide. Added an overridable _isModel for more advanced control of what's considered a model by your Collection. The success callback passed to Model#destroy is always called asynchronously now. Router#execute passes back the route name as its third argument. Cancel the current Router transition by returning false in Router#execute . Great for checking logged-in status or other prerequisites. Added getSearch and getPath methods to Backbone.History as cross-browser and overridable ways of slicing up the URL. Added delegate and undelegate as finer-grained versions of delegateEvents and undelegateEvents . Useful for plugin authors to use a consistent events interface in Backbone. A collection will only fire a "sort" event if its order was actually updated, not on every set Any passed options.attrs are now respected when saving a model with patch: true Collection#clone now sets the model and comparator functions of the cloned collection to the new one. Adding models to your Collection when specifying an at position now sends the actual position of your model in the add event, not just the one you've passed in. Collection#remove will now only return a list of models that have actually been removed from the collection. Fixed loading Backbone.js in strict ES2015 module loaders. 1.1.2 Feb. 20, 2014 Diff Docs Backbone no longer tries to require jQuery in Node/CommonJS environments, for better compatibility with folks using Browserify. If you'd like to have Backbone use jQuery from Node, assign it like so: Backbone.$ = require('jquery'); Bugfix for route parameters with newlines in them. 1.1.1 Feb. 13, 2014 Diff Docs Backbone now registers itself for AMD (Require.js), Bower and Component, as well as being a CommonJS module and a regular (Java)Script. Whew. Added an execute hook to the Router, which allows you to hook in and custom-parse route arguments, like query strings, for example. Performance fine-tuning for Backbone Events. Better matching for Unicode in routes, in old browsers. Backbone Routers now handle query params in route fragments, passing them into the handler as the last argument. Routes specified as strings should no longer include the query string 'foo?:query' should be 'foo' ). 1.1.0 Oct. 10, 2013 Diff Docs Made the return values of Collection's set add remove , and reset more useful. Instead of returning this , they now return the changed (added, removed or updated) model or list of models. Backbone Views no longer automatically attach options passed to the constructor as this.options and Backbone Models no longer attach url and urlRoot options, but you can do it yourself if you prefer. All "invalid" events now pass consistent arguments. First the model in question, then the error object, then options. You are no longer permitted to change the id of your model during parse . Use idAttribute instead. On the other hand, parse is now an excellent place to extract and vivify incoming nested JSON into associated submodels. Many tweaks, optimizations and bugfixes relating to Backbone 1.0, including URL overrides, mutation of options, bulk ordering, trailing slashes, edge-case listener leaks, nested model parsing... 1.0.0 March 20, 2013 Diff Docs Renamed Collection's "update" to set , for parallelism with the similar model.set() , and contrast with reset . It's now the default updating mechanism after a fetch . If you'd like to continue using "reset", pass {reset: true} Your route handlers will now receive their URL parameters pre-decoded. Added listenToOnce as the analogue of once Added the findWhere method to Collections, similar to where Added the keys values pairs invert pick , and omit Underscore.js methods to Backbone Models. The routes in a Router's route map may now be function literals, instead of references to methods, if you like. url and urlRoot properties may now be passed as options when instantiating a new Model. 0.9.10 Jan. 15, 2013 Diff Docs "route" event is triggered on the router in addition to being fired on Backbone.history Model validation is now only enforced by default in Model#save and no longer enforced by default upon construction or in Model#set , unless the {validate:true} option is passed. View#make has been removed. You'll need to use directly to construct DOM elements now. Passing {silent:true} on change will no longer delay individual "change:attr" events, instead they are silenced entirely. The Model#change method has been removed, as delayed attribute changes are no longer available. Bug fix on change where attribute comparison uses !== instead of _.isEqual Bug fix where an empty response from the server on save would not call the success function. parse now receives options as its second argument. Model validation now fires invalid event instead of error 0.9.9 Dec. 13, 2012 Diff Docs Added listenTo and stopListening to Events. They can be used as inversion-of-control flavors of on and off for convenient unbinding of all events an object is currently listening to. view.remove() automatically calls view.stopListening() When using add on a collection, passing {merge: true} will now cause duplicate models to have their attributes merged in to the existing models, instead of being ignored. Added update (which is also available as an option to fetch ) for "smart" updating of sets of models. HTTP PATCH support in by passing {patch: true} The Backbone object now extends Events so that you can use it as a global event bus, if you like. Added a "request" event to Backbone.sync which triggers whenever a request begins to be made to the server. The natural complement to the "sync" event. Router URLs now support optional parts via parentheses, without having to use a regex. Backbone events now supports once , similar to Node's once or jQuery's one Backbone events now support jQuery-style event maps obj.on({click: action}) While listening to a reset event, the list of previous models is now available in options.previousModels , for convenience. Validation now occurs even during "silent" changes. This change means that the isValid method has been removed. Failed validations also trigger an error, even if an error callback is specified in the options. Consolidated "sync" and "error" events within Backbone.sync . They are now triggered regardless of the existence of success or error callbacks. For mixed-mode APIs, Backbone.sync now accepts emulateHTTP and emulateJSON as inline options. Collections now also proxy Underscore method name aliases (collect, inject, foldl, foldr, head, tail, take, and so on...) Removed getByCid from Collections. collection.get now supports lookup by both id and cid After fetching a model or a collection, all defined parse functions will now be run. So fetching a collection and getting back new models could cause both the collection to parse the list, and then each model to be parsed in turn, if you have both functions defined. Bugfix for normalizing leading and trailing slashes in the Router definitions. Their presence (or absence) should not affect behavior. When declaring a View, options el tagName id and className may now be defined as functions, if you want their values to be determined at runtime. Added a Backbone.ajax hook for more convenient overriding of the default use of $.ajax . If AJAX is too passé, set it to your preferred method for server communication. Collection#sort now triggers a sort event, instead of a reset event. Calling destroy on a Model will now return false if the model isNew To set what library Backbone uses for DOM manipulation and Ajax calls, use Backbone.$ = ... instead of setDomLibrary Removed the Backbone.wrapError helper method. Overriding sync should work better for those particular use cases. To improve the performance of add options.index will no longer be set in the add event callback. collection.indexOf(model) can be used to retrieve the index of a model as necessary. For semantic and cross browser reasons, routes will now ignore search parameters. Routes like search?query=…&page=3 should become search/…/3 Model#set no longer accepts another model as an argument. This leads to subtle problems and is easily replaced with model.set(other.attributes) 0.9.2 March 21, 2012 Diff Docs Instead of throwing an error when adding duplicate models to a collection, Backbone will now silently skip them instead. Added push pop unshift , and shift to collections. A model's changed hash is now exposed for easy reading of the changed attribute delta, since the model's last "change" event. Added where to collections for simple filtering. You can now use a single off call to remove all callbacks bound to a specific object. Bug fixes for nested individual change events, some of which may be "silent". Bug fixes for URL encoding in location.hash fragments. Bug fix for client-side validation in advance of a call with {wait: true} Updated / refreshed the example Todo List app. 0.9.1 Feb. 2, 2012 Diff Docs Reverted to 0.5.3-esque behavior for validating models. Silent changes no longer trigger validation (making it easier to work with forms). Added an isValid function that you can use to check if a model is currently in a valid state. If you have multiple versions of jQuery on the page, you can now tell Backbone which one to use with Backbone.setDomLibrary Fixes regressions in 0.9.0 for routing with "root", saving with both "wait" and "validate", and the order of nested "change" events. 0.9.0 Jan. 30, 2012 Diff Docs Creating and destroying models with create and destroy are now optimistic by default. Pass {wait: true} as an option if you'd like them to wait for a successful server response to proceed. Two new properties on views: $el — a cached jQuery (or Zepto) reference to the view's element, and setElement , which should be used instead of manually setting a view's el . It will both set view.el and view.$el correctly, as well as re-delegating events on the new DOM element. You can now bind and trigger multiple spaced-delimited events at once. For example: model.on("change:name change:age", ...) When you don't know the key in advance, you may now call model.set(key, value) as well as Multiple models with the same id are no longer allowed in a single collection. Added a "sync" event, which triggers whenever a model's state has been successfully synced with the server (create, save, destroy). bind and unbind have been renamed to on and off for clarity, following jQuery's lead. The old names are also still supported. A Backbone collection's comparator function may now behave either like a sortBy (pass a function that takes a single argument), or like a sort (pass a comparator function that expects two arguments). The comparator function is also now bound by default to the collection — so you can refer to this within it. A view's events hash may now also contain direct function values as well as the string names of existing view methods. Validation has gotten an overhaul — a model's validate function will now be run even for silent changes, and you can no longer create a model in an initially invalid state. Added shuffle and initial to collections, proxied from Underscore. Model#urlRoot may now be defined as a function as well as a value. View#attributes may now be defined as a function as well as a value. Calling fetch on a collection will now cause all fetched JSON to be run through the collection's model's parse function, if one is defined. You may now tell a router to navigate(fragment, {replace: true}) which will either use history.replaceState or location.hash.replace , in order to change the URL without adding a history entry. Within a collection's add and remove events, the index of the model being added or removed is now available as options.index Added an undelegateEvents to views, allowing you to manually remove all configured event delegations. Although you shouldn't be writing your routes with them in any case — leading slashes ( ) are now stripped from routes. Calling clone on a model now only passes the attributes for duplication, not a reference to the model itself. Calling clear on a model now removes the id attribute. 0.5.3 August 9, 2011 Diff Docs A View's events property may now be defined as a function, as well as an object literal, making it easier to programmatically define and inherit events. groupBy is now proxied from Underscore as a method on Collections. If the server has already rendered everything on page load, pass Backbone.history.start({silent: true}) to prevent the initial route from triggering. Bugfix for pushState with encoded URLs. 0.5.2 July 26, 2011 Diff Docs The bind function, can now take an optional third argument, to specify the this of the callback function. Multiple models with the same id are now allowed in a collection. Fixed a bug where calling .fetch(jQueryOptions) could cause an incorrect URL to be serialized. Fixed a brief extra route fire before redirect, when degrading from pushState 0.5.1 July 5, 2011 Diff Docs Cleanups from the 0.5.0 release, to wit: improved transparent upgrades from hash-based URLs to pushState, and vice-versa. Fixed inconsistency with non-modified attributes being passed to Model#initialize . Reverted 0.5.0 change that would strip leading hashbangs from routes. Added contains as an alias for includes 0.5.0 July 1, 2011 Diff Docs A large number of tiny tweaks and micro bugfixes, best viewed by looking at the commit diff HTML5 pushState support, enabled by opting-in with: Backbone.history.start({pushState: true}) Controller was renamed to Router , for clarity. Collection#refresh was renamed to Collection#reset to emphasize its ability to both reset the collection with new models, as well as empty out the collection when used with no parameters. saveLocation was replaced with navigate RESTful persistence methods (save, fetch, etc.) now return the jQuery deferred object for further success/error chaining and general convenience. Improved XSS escaping for Model#escape Added a urlRoot option to allow specifying RESTful urls without the use of a collection. An error is thrown if Backbone.history.start is called multiple times. Collection#create now validates before initializing the new model. view.el can now be a jQuery string lookup. Backbone Views can now also take an attributes parameter. Model#defaults can now be a function as well as a literal attributes object. 0.3.3 Dec 1, 2010 Diff Docs Backbone.js now supports Zepto , alongside jQuery, as a framework for DOM manipulation and Ajax support. Implemented Model#escape , to efficiently handle attributes intended for HTML interpolation. When trying to persist a model, failed requests will now trigger an "error" event. The ubiquitous options argument is now passed as the final argument to all "change" events. 0.3.2 Nov 23, 2010 Diff Docs Bugfix for IE7 + iframe-based "hashchange" events. sync may now be overridden on a per-model, or per-collection basis. Fixed recursion error when calling with no changed attributes, within a "change" event. 0.3.1 Nov 15, 2010 Diff Docs All "add" and "remove" events are now sent through the model, so that views can listen for them without having to know about the collection. Added a remove method to Backbone.View toJSON is no longer called at all for 'read' and 'delete' requests. Backbone routes are now able to load empty URL fragments. 0.3.0 Nov 9, 2010 Diff Docs Backbone now has Controllers and History , for doing client-side routing based on URL fragments. Added emulateHTTP to provide support for legacy servers that don't do PUT and DELETE Added emulateJSON for servers that can't accept application/json encoded requests. Added Model#clear , which removes all attributes from a model. All Backbone classes may now be seamlessly inherited by CoffeeScript classes. 0.2.0 Oct 25, 2010 Diff Docs Instead of requiring server responses to be namespaced under a model key, now you can define your own parse method to convert responses into attributes for Models and Collections. The old handleEvents function is now named delegateEvents , and is automatically called as part of the View's constructor. Added a toJSON function to Collections. Added Underscore's chain to Collections. 0.1.2 Oct 19, 2010 Diff Docs Added a Model#fetch method for refreshing the attributes of single model from the server. An error callback may now be passed to set and as an option, which will be invoked if validation fails, overriding the "error" event. You can now tell backbone to use the _method hack instead of HTTP methods by setting Backbone.emulateHTTP = true Existing Model and Collection data is no longer sent up unnecessarily with GET and DELETE requests. Added a rake lint task. Backbone is now published as an NPM module. 0.1.1 Oct 14, 2010 Diff Docs Added a convention for initialize functions to be called upon instance construction, if defined. Documentation tweaks. 0.1.0 Oct 13, 2010 Docs Initial Backbone release.</div> </div> <div class="detail-actions"> <a href="/search?q=backbonejs.org" class="btn">Same domain →</a> <a href="/search?q=Backbone.js" class="btn btn-secondary">Similar titles →</a> </div> </article> </main> <footer class="site-footer"> <div class="container"> C U Cyber History — Public Interest Web Archive Preserving fading web memories. Discover history that once existed. </div> </footer> <script id="chat-i18n-en" type="application/json">{"button_label":"Need Help?","placeholder":"Ask us anything...","title":"CUCH Assistant","subtitle":"How can we help you?","send":"Send","close":"Close","folder":"/var/www/cu","greeting":"Hi! Welcome to CUCH.org. How can I help you today? Feel free to ask about our archive, search, or anything else!","error":"Sorry, our service is temporarily unavailable. Please try again later.","banner_text":"Need help? Ask our AI assistant!"}</script> <script src="/static/js/chat-widget.js"></script> </body> </html>