Class Application
publicimport Application from '@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:
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:
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:
let 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:
let 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:
let 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 events Ember components use, see components/handling-events.
Initializers
Libraries on top of Ember can add initializers, like so:
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:
let 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.
advanceReadiness public
Defined in packages/ember-application/lib/system/application.js:518
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.
deferReadiness public
Defined in packages/ember-application/lib/system/application.js:486
Use this to defer readiness until some condition is true.
Example:
let 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.
hasRegistration (fullName) Boolean public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:111
- fullName
- String
- returns
- Boolean
Check if a factory is registered.
initializer (initializer) public
Inherited from Engine packages/ember-application/lib/system/engine.js:173
- initializer
- Object
The goal of initializers should be to register dependencies and injections. This phase runs once. Because these initializers may load code, they are allowed to defer application readiness and advance it. If you need to access the container or store you should use an InstanceInitializer that will be run after all initializers and therefore after all code is loaded and the app is ready.
Initializer receives an object which has the following attributes:
name
, before
, after
, initialize
. The only required attribute is
initialize
, all others are optional.
name
allows you to specify under which name the initializer is registered. This must be a unique name, as trying to register two initializers with the same name will result in an error.
import { debug } from '@ember/debug';
export function initialize() {
debug('Running namedInitializer!');
}
export default {
name: 'named-initializer',
initialize
};
before
andafter
are used to ensure that this initializer is ran prior or after the one identified by the value. This value can be a single string or an array of strings, referencing thename
of other initializers.
An example of ordering initializers, we create an initializer named first
:
import { debug } from '@ember/debug';
export function initialize() {
debug('First initializer!');
}
export default {
name: 'first',
initialize
};
// DEBUG: First initializer!
We add another initializer named second
, specifying that it should run
after the initializer named first
:
import { debug } from '@ember/debug';
export function initialize() {
debug('Second initializer!');
}
export default {
name: 'second',
after: 'first',
initialize
};
// DEBUG: First initializer!
// DEBUG: Second initializer!
Afterwards we add a further initializer named pre
, this time specifying
that it should run before the initializer named first
:
import { debug } from '@ember/debug';
export function initialize() {
debug('Pre initializer!');
}
export default {
name: 'pre',
before: 'first',
initialize
};
// DEBUG: Pre initializer!
// DEBUG: First initializer!
// DEBUG: Second initializer!
Finally we add an initializer named post
, specifying it should run after
both the first
and the second
initializers:
import { debug } from '@ember/debug';
export function initialize() {
debug('Post initializer!');
}
export default {
name: 'post',
after: ['first', 'second'],
initialize
};
// DEBUG: Pre initializer!
// DEBUG: First initializer!
// DEBUG: Second initializer!
// DEBUG: Post initializer!
initialize
is a callback function that receives one argument,application
, on which you can operate.
Example of using application
to register an adapter:
import ApiAdapter from '../utils/api-adapter';
export function initialize(application) {
application.register('api-adapter:main', ApiAdapter);
}
export default {
name: 'post',
after: ['first', 'second'],
initialize
};
inject (factoryNameOrType, property, injectionName) public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:193
- factoryNameOrType
- String
- property
- String
- injectionName
- String
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:
let App = Ember.Application.create();
let 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.
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.
instanceInitializer (instanceInitializer) public
Inherited from Engine packages/ember-application/lib/system/engine.js:320
- instanceInitializer
Instance initializers run after all initializers have run. Because instance initializers run after the app is fully set up. We have access to the store, container, and other items. However, these initializers run after code has loaded and are not allowed to defer readiness.
Instance initializer receives an object which has the following attributes:
name
, before
, after
, initialize
. The only required attribute is
initialize
, all others are optional.
name
allows you to specify under which name the instanceInitializer is registered. This must be a unique name, as trying to register two instanceInitializer with the same name will result in an error.
import { debug } from '@ember/debug';
export function initialize() {
debug('Running named-instance-initializer!');
}
export default {
name: 'named-instance-initializer',
initialize
};
before
andafter
are used to ensure that this initializer is ran prior or after the one identified by the value. This value can be a single string or an array of strings, referencing thename
of other initializers.See Ember.Application.initializer for discussion on the usage of before and after.
Example instanceInitializer to preload data into the store.
import $ from 'jquery';
export function initialize(application) {
var userConfig, userConfigEncoded, store;
// We have a HTML escaped JSON representation of the user's basic
// configuration generated server side and stored in the DOM of the main
// index.html file. This allows the app to have access to a set of data
// without making any additional remote calls. Good for basic data that is
// needed for immediate rendering of the page. Keep in mind, this data,
// like all local models and data can be manipulated by the user, so it
// should not be relied upon for security or authorization.
// Grab the encoded data from the meta tag
userConfigEncoded = $('head meta[name=app-user-config]').attr('content');
// Unescape the text, then parse the resulting JSON into a real object
userConfig = JSON.parse(unescape(userConfigEncoded));
// Lookup the store
store = application.lookup('service:store');
// Push the encoded JSON into the store
store.pushPayload(userConfig);
}
export default {
name: 'named-instance-initializer',
initialize
};
register (fullName, factory, options) public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:30
- fullName
- String
type:name (e.g., 'model:user')
- factory
- Function
(e.g., App.Person)
- options
- Object
(optional) disable instantiation or singleton usage
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:
let 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:
let App = Ember.Application.create();
let 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:
let 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 });
registerOptions (fullName, options) public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:132
- fullName
- String
- options
- Object
Register options for a particular factory.
registerOptionsForType (type, options) public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:152
- type
- String
- options
- Object
Allow registering options for all factories of a type.
let App = Ember.Application.create();
let appInstance = App.buildInstance();
// if all of type `connection` must not be singletons
appInstance.registerOptionsForType('connection', { singleton: false });
appInstance.register('connection:twitter', TwitterConnection);
appInstance.register('connection:facebook', FacebookConnection);
let twitter = appInstance.lookup('connection:twitter');
let twitter2 = appInstance.lookup('connection:twitter');
twitter === twitter2; // => false
let facebook = appInstance.lookup('connection:facebook');
let facebook2 = appInstance.lookup('connection:facebook');
facebook === facebook2; // => false
registeredOption (fullName, optionName) Object public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:121
- fullName
- String
- optionName
- String
- returns
- Object
options
Return a specific registered option for a particular factory.
registeredOptions (fullName) Object public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:142
- fullName
- String
- returns
- Object
options
Return registered options for a particular factory.
registeredOptionsForType (type) Object public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:183
- type
- String
- returns
- Object
options
Return the registered options for all factories of a type.
reset public
Defined in packages/ember-application/lib/system/application.js:602
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:
let 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.
let 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
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:20
- fullName
- String
- returns
- Function
fullName's factory
Given a fullName return the corresponding factory.
unregister (fullName) public
Inherited from RegistryProxyMixin packages/ember-runtime/lib/mixins/registry_proxy.js:91
- fullName
- String
Unregister a factory.
let App = Ember.Application.create();
let 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
visit (url, options) Promise<ApplicationInstance, Error> public
Defined in packages/ember-application/lib/system/application.js:770
- url
- String
The initial URL to navigate to
- options
- ApplicationInstance.BootOptions
- returns
- Promise<ApplicationInstance, Error>
Boot 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 occurred 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:
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 foreign 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:
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:
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.
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 needs 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 fulfill a given request and eagerly "push" these resources to the client.
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 appropriate implementation 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
};
import Route from '@ember/routing/route';
// An example of how the (hypothetical) service is used in routes.
export default 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;
}
}
});
// 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": "..." }
});
}