Class ApplicationInstance

public
import ApplicationInstance from '@ember/application/instance';

The ApplicationInstance encapsulates all of the stateful aspects of a running Application.

At a high-level, we break application boot into two distinct phases:

  • Definition time, where all of the classes, templates, and other dependencies are loaded (typically in the browser).
  • Run time, where we begin executing the application once everything has loaded.

Definition time can be expensive and only needs to happen once since it is an idempotent operation. For example, between test runs and FastBoot requests, the application stays the same. It is only the state that we want to reset.

That state is what the ApplicationInstance manages: it is responsible for creating the container that contains all application state, and disposing of it once the particular test run or FastBoot request has finished.

Show:

key
String
The key to observe
target
Object
The target object to invoke
method
String|Function
The method to invoke
returns
Observable

Adds an observer on a property.

This is the core method used to register an observer for a property.

Once you call this method, any time the key's value is set, your observer will be notified. Note that the observers are triggered any time the value is set, regardless of whether it has actually changed. Your observer should be prepared to handle that.

Observer Methods

Observer methods have the following signature:

component.js
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import Component from '@ember/component';

export default Component.extend({
  init() {
    this._super(...arguments);
    this.addObserver('foo', this, 'fooDidChange');
  },

  fooDidChange(sender, key, value, rev) {
    // your code
  }
});

The sender is the object that changed. The key is the property that changes. The value property is currently reserved and unused. The rev is the last property revision of the object when it changed, which you can use to detect if the key value has really changed or not.

Usually you will not need the value or revision parameters at the end. In this case, it is common to write observer methods that take only a sender and key value as parameters or, if you aren't interested in any of these values, to write an observer that has no parameters at all.

keyName
String
returns
Object
The cached value of the computed property, if any

Returns the cached value of a computed property, if it exists. This allows you to inspect the value of a computed property without accidentally invoking it if it is intended to be generated lazily.

keyName
String
The name of the property to decrement
decrement
Number
The amount to decrement by. Defaults to 1
returns
Number
The new property value

Set the value of a property to the current value minus some amount.

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player.decrementProperty('lives');
orc.decrementProperty('health', 5);
returns
EmberObject
receiver

Destroys an object by setting the isDestroyed flag and removing its metadata, which effectively destroys observers and bindings.

If you try to set a property on a destroyed object, an exception will be raised.

Note that destruction is scheduled for the end of the run loop and does not happen immediately. It will set an isDestroying flag immediately.

fullName
String
options
Object
returns
FactoryManager

Given a fullName return a factory manager.

This method returns a manager which can be used for introspection of the factory's class or for the creation of factory instances with initial properties. The manager is an object with the following properties:

  • class - The registered or resolved class.
  • create - A function that will create an instance of the class with any dependencies injected.

    For example:

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    import { getOwner } from '@ember/application';
    
    let owner = getOwner(otherInstance);
    // the owner is commonly the `applicationInstance`, and can be accessed via
    // an instance initializer.
    
    let factory = owner.factoryFor('service:bespoke');
    
    factory.class;
    // The registered or resolved class. For example when used with an Ember-CLI
    // app, this would be the default export from `app/services/bespoke.js`.
    
    let instance = factory.create({
    someProperty: 'an initial property value'
    });
    // Create an instance with any injections and the passed options as
    // initial properties.
keyName
String
The property to retrieve
returns
Object
The property value or undefined.

Retrieves the value of a property from the object.

This method is usually similar to using object[keyName] or object.keyName, however it supports both computed properties and the unknownProperty handler.

Because get unifies the syntax for accessing all these kinds of properties, it can make many refactorings easier, such as replacing a simple property with a computed property, or vice versa.

Computed Properties

Computed properties are methods defined with the property modifier declared at the end, such as:

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import { computed } from '@ember/object';

fullName: computed('firstName', 'lastName', function() {
  return this.get('firstName') + ' ' + this.get('lastName');
})

When you call get on a computed property, the function will be called and the return value will be returned instead of the function itself.

Unknown Properties

Likewise, if you try to call get on a property whose value is undefined, the unknownProperty() method will be called on the object. If this method returns any value other than undefined, it will be returned instead. This allows you to implement "virtual" properties that are not defined upfront.

list
String...|Array
of keys to get
returns
Object

To get the values of multiple properties at once, call getProperties with a list of strings or an array:

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record.getProperties('firstName', 'lastName', 'zipCode');
// { firstName: 'John', lastName: 'Doe', zipCode: '10011' }

is equivalent to:

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record.getProperties(['firstName', 'lastName', 'zipCode']);
// { firstName: 'John', lastName: 'Doe', zipCode: '10011' }
keyName
String
The name of the property to retrieve
defaultValue
Object
The value to return if the property value is undefined
returns
Object
The property value or the defaultValue.

Retrieves the value of a property, or a default value in the case that the property returns undefined.

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person.getWithDefault('lastName', 'Doe');
fullName
String
returns
Boolean

Check if a factory is registered.

keyName
String
The name of the property to increment
increment
Number
The amount to increment by. Defaults to 1
returns
Number
The new property value

Set the value of a property to the current value plus some amount.

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person.incrementProperty('age');
team.incrementProperty('score', 2);

An overridable method called when objects are instantiated. By default, does nothing unless it is overridden during class definition.

Example:

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import EmberObject from '@ember/object';

const Person = EmberObject.extend({
  init() {
    alert(`Name is ${this.get('name')}`);
  }
});

let steve = Person.create({
  name: 'Steve'
});

// alerts 'Name is Steve'.

NOTE: If you do override init for a framework class like Ember.View, be sure to call this._super(...arguments) in your init declaration! If you don't, Ember may not have an opportunity to do important setup work, and you'll see strange behavior in your application.

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:

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import { alias } from '@ember/object/computed';
import Application from '@ember/application';
import Controller from '@ember/controller';
import EmberObject from '@ember/object';

let App = Application.create();
let Session = EmberObject.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 = Controller.extend({
  isLoggedIn: 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.

fullName
String
options
Object
returns
Any

Given a fullName return a corresponding instance.

The default behavior is for lookup to return a singleton instance. The singleton is scoped to the container, allowing multiple containers to all have their own locally scoped singletons.

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let registry = new Registry();
let container = registry.container();

registry.register('api:twitter', Twitter);

let twitter = container.lookup('api:twitter');

twitter instanceof Twitter; // => true

// by default the container will return singletons
let twitter2 = container.lookup('api:twitter');
twitter2 instanceof Twitter; // => true

twitter === twitter2; //=> true

If singletons are not wanted an optional flag can be provided at lookup.

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let registry = new Registry();
let container = registry.container();

registry.register('api:twitter', Twitter);

let twitter = container.lookup('api:twitter', { singleton: false });
let twitter2 = container.lookup('api:twitter', { singleton: false });

twitter === twitter2; //=> false
keyName
String
The property key to be notified about.
returns
Observable

Notify the observer system that a property has just changed.

Sometimes you need to change a value directly or indirectly without actually calling get() or set() on it. In this case, you can use this method instead. Calling this method will notify all observers that the property has potentially changed value.

returns
Object

Returns an object that can be used to provide an owner to a manually created instance.

Example:

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import { getOwner } from '@ember/application';

let owner = getOwner(this);

User.create(
  owner.ownerInjection(),
  { username: 'rwjblue' }
)
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:

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import Application from '@ember/application';
import EmberObject from '@ember/object';

let App = Application.create();

App.Orange = EmberObject.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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import Application from '@ember/application';
import Controller from '@ember/controller';

let App = Application.create();
let Session = 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 = 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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import Application from '@ember/application';
import EmberObject from '@ember/object';

let App = Application.create();

App.Person = EmberObject.extend();
App.Orange = EmberObject.extend();
App.Email = EmberObject.extend();
App.session = EmberObject.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 });
fullName
String
options
Object

Register options for a particular factory.

type
String
options
Object

Allow registering options for all factories of a type.

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import Application from '@ember/application';

let App = 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
fullName
String
optionName
String
returns
Object
options

Return a specific registered option for a particular factory.

fullName
String
returns
Object
options

Return registered options for a particular factory.

type
String
returns
Object
options

Return the registered options for all factories of a type.

key
String
The key to observe
target
Object
The target object to invoke
method
String|Function
The method to invoke
returns
Observable

Remove an observer you have previously registered on this object. Pass the same key, target, and method you passed to addObserver() and your target will no longer receive notifications.

fullName
String
returns
Function
fullName's factory

Given a fullName return the corresponding factory.

keyName
String
The property to set
value
Object
The value to set or `null`.
returns
Object
The passed value

Sets the provided key or path to the value.

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record.set("key", value);

This method is generally very similar to calling object["key"] = value or object.key = value, except that it provides support for computed properties, the setUnknownProperty() method and property observers.

Computed Properties

If you try to set a value on a key that has a computed property handler defined (see the get() method for an example), then set() will call that method, passing both the value and key instead of simply changing the value itself. This is useful for those times when you need to implement a property that is composed of one or more member properties.

Unknown Properties

If you try to set a value on a key that is undefined in the target object, then the setUnknownProperty() handler will be called instead. This gives you an opportunity to implement complex "virtual" properties that are not predefined on the object. If setUnknownProperty() returns undefined, then set() will simply set the value on the object.

Property Observers

In addition to changing the property, set() will also register a property change with the object. Unless you have placed this call inside of a beginPropertyChanges() and endPropertyChanges(), any "local" observers (i.e. observer methods declared on the same object), will be called immediately. Any "remote" observers (i.e. observer methods declared on another object) will be placed in a queue and called at a later time in a coalesced manner.

hash
Object
the hash of keys and values to set
returns
Object
The passed in hash

Sets a list of properties at once. These properties are set inside a single beginPropertyChanges and endPropertyChanges batch, so observers will be buffered.

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record.setProperties({ firstName: 'Charles', lastName: 'Jolley' });
returns
String
string representation

Returns a string representation which attempts to provide more information than Javascript's toString typically does, in a generic way for all Ember objects.

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import EmberObject from '@ember/object';

const Person = EmberObject.extend();
person = Person.create();
person.toString(); //=> "<Person:ember1024>"

If the object's class is not defined on an Ember namespace, it will indicate it is a subclass of the registered superclass:

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const Student = Person.extend();
let student = Student.create();
student.toString(); //=> "<(subclass of Person):ember1025>"

If the method toStringExtension is defined, its return value will be included in the output.

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const Teacher = Person.extend({
  toStringExtension() {
    return this.get('fullName');
  }
});
teacher = Teacher.create();
teacher.toString(); //=> "<Teacher:ember1026:Tom Dale>"
keyName
String
The name of the property to toggle
returns
Boolean
The new property value

Set the value of a boolean property to the opposite of its current value.

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starship.toggleProperty('warpDriveEngaged');
fullName
String

Unregister a factory.

Overrides RegistryProxy#unregister in order to clear any cached instances of the unregistered factory.

Override to implement teardown.