Ember.Application Class packages/ember-application/lib/system/application.js:51
PUBLIC
Extends: Ember.Engine
Uses: RegistryProxyMixin
Defined in: packages/ember-application/lib/system/application.js:51
Module: ember-application
An instance of Ember.Application
is the starting point for every Ember
application. It helps to instantiate, initialize and coordinate the many
objects that make up your app.
Each Ember app has one and only one Ember.Application
object. In fact, the
very first thing you should do in your application is create the instance:
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window.App = Ember.Application.create(); |
Typically, the application object is the only global variable. All other
classes in your app should be properties on the Ember.Application
instance,
which highlights its first role: a global namespace.
For example, if you define a view class, it might look like this:
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App.MyView = Ember.View.extend(); |
By default, calling Ember.Application.create()
will automatically initialize
your application by calling the Ember.Application.initialize()
method. If
you need to delay initialization, you can call your app's deferReadiness()
method. When you are ready for your app to be initialized, call its
advanceReadiness()
method.
You can define a ready
method on the Ember.Application
instance, which
will be run by Ember when the application is initialized.
Because Ember.Application
inherits from Ember.Namespace
, any classes
you create will have useful string representations when calling toString()
.
See the Ember.Namespace
documentation for more information.
While you can think of your Ember.Application
as a container that holds the
other classes in your application, there are several other responsibilities
going on under-the-hood that you may want to understand.
Event Delegation
Ember uses a technique called event delegation. This allows the framework
to set up a global, shared event listener instead of requiring each view to
do it manually. For example, instead of each view registering its own
mousedown
listener on its associated element, Ember sets up a mousedown
listener on the body
.
If a mousedown
event occurs, Ember will look at the target of the event and
start walking up the DOM node tree, finding corresponding views and invoking
their mouseDown
method as it goes.
Ember.Application
has a number of default events that it listens for, as
well as a mapping from lowercase events to camel-cased view method names. For
example, the keypress
event causes the keyPress
method on the view to be
called, the dblclick
event causes doubleClick
to be called, and so on.
If there is a bubbling browser event that Ember does not listen for by
default, you can specify custom events and their corresponding view method
names by setting the application's customEvents
property:
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var App = Ember.Application.create({ customEvents: { // add support for the paste event paste: 'paste' } }); |
To prevent Ember from setting up a listener for a default event,
specify the event name with a null
value in the customEvents
property:
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var App = Ember.Application.create({ customEvents: { // prevent listeners for mouseenter/mouseleave events mouseenter: null, mouseleave: null } }); |
By default, the application sets up these event listeners on the document body. However, in cases where you are embedding an Ember application inside an existing page, you may want it to set up the listeners on an element inside the body.
For example, if only events inside a DOM element with the ID of ember-app
should be delegated, set your application's rootElement
property:
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var App = Ember.Application.create({ rootElement: '#ember-app' }); |
The rootElement
can be either a DOM element or a jQuery-compatible selector
string. Note that views appended to the DOM outside the root element will
not receive events. If you specify a custom root element, make sure you only
append views inside it!
To learn more about the advantages of event delegation and the Ember view layer, and a list of the event listeners that are setup by default, visit the Ember View Layer guide.
Initializers
Libraries on top of Ember can add initializers, like so:
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Ember.Application.initializer({ name: 'api-adapter', initialize: function(application) { application.register('api-adapter:main', ApiAdapter); } }); |
Initializers provide an opportunity to access the internal registry, which organizes the different components of an Ember application. Additionally they provide a chance to access the instantiated application. Beyond being used for libraries, initializers are also a great way to organize dependency injection or setup in your own application.
Routing
In addition to creating your application's router, Ember.Application
is
also responsible for telling the router when to start routing. Transitions
between routes can be logged with the LOG_TRANSITIONS
flag, and more
detailed intra-transition logging can be logged with
the LOG_TRANSITIONS_INTERNAL
flag:
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var App = Ember.Application.create({ LOG_TRANSITIONS: true, // basic logging of successful transitions LOG_TRANSITIONS_INTERNAL: true // detailed logging of all routing steps }); |
By default, the router will begin trying to translate the current URL into
application state once the browser emits the DOMContentReady
event. If you
need to defer routing, you can call the application's deferReadiness()
method. Once routing can begin, call the advanceReadiness()
method.
If there is any setup required before routing begins, you can implement a
ready()
method on your app that will be invoked immediately before routing
begins.
Methods
- _prepareForGlobalsMode
- advanceReadiness
- boot
- buildInstance
- buildRegistry
- deferReadiness
- didBecomeReady
- domReady
- hasRegistration
- inject
- register
- registerOption
- registerOptions
- registerOptionsForType
- registeredOption
- registeredOptions
- registeredOptionsForType
- reset
- resolveRegistration
- unregister
- visit
- waitForDOMReady
Properties
Events
_prepareForGlobalsMode
private
Enable the legacy globals mode by allowing this application to act
as a global namespace. See the docs on the _globalsMode
property
for details.
Most of these features are already deprecated in 1.x, so we can stop using them internally and try to remove them.
advanceReadiness
public
Call advanceReadiness
after any asynchronous setup logic has completed.
Each call to deferReadiness
must be matched by a call to advanceReadiness
or the application will never become ready and routing will not begin.
boot
PromiseInitialize the application and return a promise that resolves with the Ember.Application
object when the boot process is complete.
Run any application initializers and run the application load hook. These hooks may choose to defer readiness. For example, an authentication hook might want to defer readiness until the auth token has been retrieved.
By default, this method is called automatically on "DOM ready"; however, if autoboot
is disabled, this is automatically called when the first application instance is
created via visit
.
Returns:
- Promise
buildInstance
Ember.ApplicationInstance
private
Create an ApplicationInstance for this application.
Returns:
- Ember.ApplicationInstance
- the application instance
buildRegistry
(namespace)
Ember.Registry
public
static
This creates a registry with the default Ember naming conventions.
It also configures the registry:
- registered views are created every time they are looked up (they are not singletons)
- registered templates are not factories; the registered value is returned directly.
- the router receives the application as its
namespace
property - all controllers receive the router as their
target
andcontrollers
properties - all controllers receive the application as their
namespace
property - the application view receives the application controller as its
controller
property - the application view receives the application template as its
defaultTemplate
property
Parameters:
- namespace Ember.Application
- the application for which to build the registry
Returns:
- Ember.Registry
- the built registry
deferReadiness
public
Use this to defer readiness until some condition is true.
Example:
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var App = Ember.Application.create(); App.deferReadiness(); // Ember.$ is a reference to the jQuery object/function Ember.$.getJSON('/auth-token', function(token) { App.token = token; App.advanceReadiness(); }); |
This allows you to perform asynchronous setup logic and defer booting your application until the setup has finished.
However, if the setup requires a loading UI, it might be better to use the router for this purpose.
didBecomeReady
private
domReady
private
This is the autoboot flow:
- Boot the app by calling
this.boot()
- Create an instance (or use the
__deprecatedInstance__
in globals mode) - Boot the instance by calling
instance.boot()
- Invoke the
App.ready()
callback - Kick-off routing on the instance
Ideally, this is all we would need to do:
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_autoBoot() { this.boot().then(() => { let instance = (this._globalsMode) ? this.__deprecatedInstance__ : this.buildInstance(); return instance.boot(); }).then((instance) => { App.ready(); instance.startRouting(); }); } |
Unfortunately, we cannot actually write this because we need to participate
in the "synchronous" boot process. While the code above would work fine on
the initial boot (i.e. DOM ready), when App.reset()
is called, we need to
boot a new instance synchronously (see the documentation on _bootSync()
for details).
Because of this restriction, the actual logic of this method is located
inside didBecomeReady()
.
hasRegistration
(fullName)
Boolean
public
Check if a factory is registered.
Parameters:
- fullName String
Returns:
- Boolean
inject
(factoryNameOrType, property, injectionName)
public
Define a dependency injection onto a specific factory or all factories of a type.
When Ember instantiates a controller, view, or other framework component it can attach a dependency to that component. This is often used to provide services to a set of framework components.
An example of providing a session object to all controllers:
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var App = Ember.Application.create(); var Session = Ember.Object.extend({ isAuthenticated: false }); // A factory must be registered before it can be injected App.register('session:main', Session); // Inject 'session:main' onto all factories of the type 'controller' // with the name 'session' App.inject('controller', 'session', 'session:main'); App.IndexController = Ember.Controller.extend({ isLoggedIn: Ember.computed.alias('session.isAuthenticated') }); |
Injections can also be performed on specific factories.
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App.inject(<full_name or type>, <property name>, <full_name>) App.inject('route', 'source', 'source:main') App.inject('route:application', 'email', 'model:email') |
It is important to note that injections can only be performed on
classes that are instantiated by Ember itself. Instantiating a class
directly (via create
or new
) bypasses the dependency injection
system.
Note: Ember-Data instantiates its models in a unique manner, and consequently
injections onto models (or all models) will not work as expected. Injections
on models can be enabled by setting Ember.MODEL_FACTORY_INJECTIONS
to true
.
register
(fullName, factory, options)
public
Registers a factory that can be used for dependency injection (with
inject
) or for service lookup. Each factory is registered with
a full name including two parts: type:name
.
A simple example:
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var App = Ember.Application.create(); App.Orange = Ember.Object.extend(); App.register('fruit:favorite', App.Orange); |
Ember will resolve factories from the App
namespace automatically.
For example App.CarsController
will be discovered and returned if
an application requests controller:cars
.
An example of registering a controller with a non-standard name:
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var App = Ember.Application.create(); var Session = Ember.Controller.extend(); App.register('controller:session', Session); // The Session controller can now be treated like a normal controller, // despite its non-standard name. App.ApplicationController = Ember.Controller.extend({ needs: ['session'] }); |
Registered factories are instantiated by having create
called on them. Additionally they are singletons, each time
they are looked up they return the same instance.
Some examples modifying that default behavior:
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var App = Ember.Application.create(); App.Person = Ember.Object.extend(); App.Orange = Ember.Object.extend(); App.Email = Ember.Object.extend(); App.session = Ember.Object.create(); App.register('model:user', App.Person, { singleton: false }); App.register('fruit:favorite', App.Orange); App.register('communication:main', App.Email, { singleton: false }); App.register('session', App.session, { instantiate: false }); |
registerOption
(fullName, optionName, options)
public
Register an option for a particular factory.
registerOptions
(fullName, options)
public
Register options for a particular factory.
Parameters:
- fullName String
- options Object
registerOptionsForType
(type, options)
public
Allow registering options for all factories of a type.
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var App = Ember.Application.create(); var appInstance = App.buildInstance(); // if all of type `connection` must not be singletons appInstance.optionsForType('connection', { singleton: false }); appInstance.register('connection:twitter', TwitterConnection); appInstance.register('connection:facebook', FacebookConnection); var twitter = appInstance.lookup('connection:twitter'); var twitter2 = appInstance.lookup('connection:twitter'); twitter === twitter2; // => false var facebook = appInstance.lookup('connection:facebook'); var facebook2 = appInstance.lookup('connection:facebook'); facebook === facebook2; // => false |
Parameters:
- type String
- options Object
registeredOption
(fullName, optionName)
Object
public
Return a specific registered option for a particular factory.
Returns:
- Object
- options
registeredOptions
(fullName)
Object
public
Return registered options for a particular factory.
Parameters:
- fullName String
Returns:
- Object
- options
registeredOptionsForType
(type)
Object
public
Return the registered options for all factories of a type.
Parameters:
- type String
Returns:
- Object
- options
reset
public
Reset the application. This is typically used only in tests. It cleans up the application in the following order:
- Deactivate existing routes
- Destroy all objects in the container
- Create a new application container
- Re-route to the existing url
Typical Example:
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var App; run(function() { App = Ember.Application.create(); }); module('acceptance test', { setup: function() { App.reset(); } }); test('first test', function() { // App is freshly reset }); test('second test', function() { // App is again freshly reset }); |
Advanced Example:
Occasionally you may want to prevent the app from initializing during setup. This could enable extra configuration, or enable asserting prior to the app becoming ready.
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var App; run(function() { App = Ember.Application.create(); }); module('acceptance test', { setup: function() { run(function() { App.reset(); App.deferReadiness(); }); } }); test('first test', function() { ok(true, 'something before app is initialized'); run(function() { App.advanceReadiness(); }); ok(true, 'something after app is initialized'); }); |
resolveRegistration
(fullName)
Function
public
Given a fullName return the corresponding factory.
Parameters:
- fullName String
Returns:
- Function
- fullName's factory
unregister
(fullName)
public
Unregister a factory.
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var App = Ember.Application.create(); var User = Ember.Object.extend(); App.register('model:user', User); App.resolveRegistration('model:user').create() instanceof User //=> true App.unregister('model:user') App.resolveRegistration('model:user') === undefined //=> true |
Parameters:
- fullName String
visit
(url, options)
PromiseBoot a new instance of Ember.ApplicationInstance
for the current
application and navigate it to the given url
. Returns a Promise
that
resolves with the instance when the initial routing and rendering is
complete, or rejects with any error that occured during the boot process.
When autoboot
is disabled, calling visit
would first cause the
application to boot, which runs the application initializers.
This method also takes a hash of boot-time configuration options for
customizing the instance's behavior. See the documentation on
Ember.ApplicationInstance.BootOptions
for details.
Ember.ApplicationInstance.BootOptions
is an interface class that exists
purely to document the available options; you do not need to construct it
manually. Simply pass a regular JavaScript object containing of the
desired options:
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MyApp.visit("/", { location: "none", rootElement: "#container" }); |
Supported Scenarios
While the BootOptions
class exposes a large number of knobs, not all
combinations of them are valid; certain incompatible combinations might
result in unexpected behavior.
For example, booting the instance in the full browser environment
while specifying a foriegn document
object (e.g. { isBrowser: true,
document: iframe.contentDocument }
) does not work correctly today,
largely due to Ember's jQuery dependency.
Currently, there are three officially supported scenarios/configurations. Usages outside of these scenarios are not guaranteed to work, but please feel free to file bug reports documenting your experience and any issues you encountered to help expand support.
Browser Applications (Manual Boot)
The setup is largely similar to how Ember works out-of-the-box. Normally,
Ember will boot a default instance for your Application on "DOM ready".
However, you can customize this behavior by disabling autoboot
.
For example, this allows you to render a miniture demo of your application into a specific area on your marketing website:
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import MyApp from 'my-app'; $(function() { let App = MyApp.create({ autoboot: false }); let options = { // Override the router's location adapter to prevent it from updating // the URL in the address bar location: 'none', // Override the default `rootElement` on the app to render into a // specific `div` on the page rootElement: '#demo' }; // Start the app at the special demo URL App.visit('/demo', options); }); |
Or perhaps you might want to boot two instances of your app on the same page for a split-screen multiplayer experience:
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import MyApp from 'my-app'; $(function() { let App = MyApp.create({ autoboot: false }); let sessionId = MyApp.generateSessionID(); let player1 = App.visit(`/matches/join?name=Player+1&session=${sessionId}`, { rootElement: '#left', location: 'none' }); let player2 = App.visit(`/matches/join?name=Player+2&session=${sessionId}`, { rootElement: '#right', location: 'none' }); Promise.all([player1, player2]).then(() => { // Both apps have completed the initial render $('#loading').fadeOut(); }); }); |
Do note that each app instance maintains their own registry/container, so they will run in complete isolation by default.
Server-Side Rendering (also known as FastBoot)
This setup allows you to run your Ember app in a server environment using Node.js and render its content into static HTML for SEO purposes.
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const HTMLSerializer = new SimpleDOM.HTMLSerializer(SimpleDOM.voidMap); function renderURL(url) { let dom = new SimpleDOM.Document(); let rootElement = dom.body; let options = { isBrowser: false, document: dom, rootElement: rootElement }; return MyApp.visit(options).then(instance => { try { return HTMLSerializer.serialize(rootElement.firstChild); } finally { instance.destroy(); } }); } |
In this scenario, because Ember does not have access to a global document
object in the Node.js environment, you must provide one explicitly. In practice,
in the non-browser environment, the stand-in document
object only need to
implement a limited subset of the full DOM API. The SimpleDOM
library is known
to work.
Since there is no access to jQuery in the non-browser environment, you must also
specify a DOM Element
object in the same document
for the rootElement
option
(as opposed to a selector string like "body"
).
See the documentation on the isBrowser
, document
and rootElement
properties
on Ember.ApplicationInstance.BootOptions
for details.
Server-Side Resource Discovery
This setup allows you to run the routing layer of your Ember app in a server environment using Node.js and completely disable rendering. This allows you to simulate and discover the resources (i.e. AJAX requests) needed to fufill a given request and eagerly "push" these resources to the client.
app/initializers/network-service.js | |
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import BrowserNetworkService from 'app/services/network/browser'; import NodeNetworkService from 'app/services/network/node'; // Inject a (hypothetical) service for abstracting all AJAX calls and use // the appropiate implementaion on the client/server. This also allows the // server to log all the AJAX calls made during a particular request and use // that for resource-discovery purpose. export function initialize(application) { if (window) { // browser application.register('service:network', BrowserNetworkService); } else { // node application.register('service:network', NodeNetworkService); } application.inject('route', 'network', 'service:network'); }; export default { name: 'network-service', initialize: initialize }; |
app/routes/post.js | |
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import Ember from 'ember'; // An example of how the (hypothetical) service is used in routes. export default Ember.Route.extend({ model(params) { return this.network.fetch(`/api/posts/${params.post_id}.json`); }, afterModel(post) { if (post.isExternalContent) { return this.network.fetch(`/api/external/?url=${post.externalURL}`); } else { return post; } } }); |
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// Finally, put all the pieces together function discoverResourcesFor(url) { return MyApp.visit(url, { isBrowser: false, shouldRender: false }).then(instance => { let networkService = instance.lookup('service:network'); return networkService.requests; // => { "/api/posts/123.json": "..." } }); } |
Parameters:
- url String
- The initial URL to navigate to
- options Ember.ApplicationInstance.BootOptions
Returns:
- Promise
waitForDOMReady
private
Automatically kick-off the boot process for the application once the DOM has become ready.
The initialization itself is scheduled on the actions queue which ensures that code-loading finishes before booting.
If you are asynchronously loading code, you should call deferReadiness()
to defer booting, and then call advanceReadiness()
once all of your code
has finished loading.
_globalsMode
Boolean
private
Whether the application should be configured for the legacy "globals mode". Under this mode, the Application object serves as a global namespace for all classes.
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var App = Ember.Application.create({ ... }); App.Router.reopen({ location: 'none' }); App.Router.map({ ... }); App.MyComponent = Ember.Component.extend({ ... }); |
This flag also exposes other internal APIs that assumes the existence of
a special "default instance", like App.__container__.lookup(...)
.
This option is currently not configurable, its value is derived from
the autoboot
flag – disabling autoboot
also implies opting-out of
globals mode support, although they are ultimately orthogonal concerns.
Some of the global modes features are already deprecated in 1.x. The existence of this flag is to untangle the globals mode code paths from the autoboot code paths, so that these legacy features can be reviewed for deprecation/removal separately.
Forcing the (autoboot=true, _globalsMode=false) here and running the tests would reveal all the places where we are still relying on these legacy behavior internally (mostly just tests).
Default: true
autoboot
Boolean
private
Whether the application should automatically start routing and render
templates to the rootElement
on DOM ready. While default by true,
other environments such as FastBoot or a testing harness can set this
property to false
and control the precise timing and behavior of the boot
process.
Default: true
customEvents
Object
public
The DOM events for which the event dispatcher should listen.
By default, the application's Ember.EventDispatcher
listens
for a set of standard DOM events, such as mousedown
and
keyup
, and delegates them to your application's Ember.View
instances.
If you would like additional bubbling events to be delegated to your
views, set your Ember.Application
's customEvents
property
to a hash containing the DOM event name as the key and the
corresponding view method name as the value. Setting an event to
a value of null
will prevent a default event listener from being
added for that event.
To add new events to be listened to:
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var App = Ember.Application.create({ customEvents: { // add support for the paste event paste: 'paste' } }); |
To prevent default events from being listened to:
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var App = Ember.Application.create({ customEvents: { // remove support for mouseenter / mouseleave events mouseenter: null, mouseleave: null } }); |
Default: null
eventDispatcher
Ember.EventDispatcher
public
The Ember.EventDispatcher
responsible for delegating events to this
application's views.
The event dispatcher is created by the application at initialization time
and sets up event listeners on the DOM element described by the
application's rootElement
property.
See the documentation for Ember.EventDispatcher
for more information.
Default: null
rootElement
DOMElement
public
The root DOM element of the Application. This can be specified as an element or a jQuery-compatible selector string.
This is the element that will be passed to the Application's,
eventDispatcher
, which sets up the listeners for event delegation. Every
view in your application should be a child of the element you specify here.
Default: 'body'
ready
public
Called when the Application has become ready, immediately before routing begins. The call will be delayed until the DOM has become ready.