Extends: | Ember.Namespace |
---|---|
Uses: | RegistryProxy |
Defined in: | packages/ember-application/lib/system/engine.js:35 |
Module: | ember |
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:333
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 have the following signature:
export default Ember.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.
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:485
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.
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:669
Creates an instance of a class. Accepts either no arguments, or an object containing values to initialize the newly instantiated object with.
const Person = Ember.Object.extend({ helloWorld() { alert(`Hi, my name is ${this.get('name')}`); } }); let tom = Person.create({ name: 'Tom Dale' }); tom.helloWorld(); // alerts "Hi, my name is Tom Dale".
create
will call the init
function if defined during Ember.AnyObject.extend
If no arguments are passed to create
, it will not set values to the new instance during initialization:
let noName = Person.create(); noName.helloWorld(); // alerts undefined
NOTE: For performance reasons, you cannot declare methods or computed properties during create
. You should instead declare methods and computed properties when using extend
.
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:448
Set the value of a property to the current value minus some amount.
player.decrementProperty('lives'); orc.decrementProperty('health', 5);
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:446
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.
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:561
Creates a new subclass.
const Person = Ember.Object.extend({ say(thing) { alert(thing); } });
This defines a new subclass of Ember.Object: Person
. It contains one method: say()
.
You can also create a subclass from any existing class by calling its extend()
method. For example, you might want to create a subclass of Ember's built-in Ember.Component
class:
const PersonComponent = Ember.Component.extend({ tagName: 'li', classNameBindings: ['isAdministrator'] });
When defining a subclass, you can override methods but still access the implementation of your parent class by calling the special _super()
method:
const Person = Ember.Object.extend({ say(thing) { let name = this.get('name'); alert(`${name} says: ${thing}`); } }); const Soldier = Person.extend({ say(thing) { this._super(`${thing}, sir!`); }, march(numberOfHours) { alert(`${this.get('name')} marches for ${numberOfHours} hours.`); } }); let yehuda = Soldier.create({ name: 'Yehuda Katz' }); yehuda.say('Yes'); // alerts "Yehuda Katz says: Yes, sir!"
The create()
on line #17 creates an instance of the Soldier
class. The extend()
on line #8 creates a subclass of Person
. Any instance of the Person
class will not have the march()
method.
You can also pass Mixin
classes to add additional properties to the subclass.
const Person = Ember.Object.extend({ say(thing) { alert(`${this.get('name')} says: ${thing}`); } }); const SingingMixin = Mixin.create({ sing(thing){ alert(`${this.get('name')} sings: la la la ${thing}`); } }); const BroadwayStar = Person.extend(SingingMixin, { dance() { alert(`${this.get('name')} dances: tap tap tap tap `); } });
The BroadwayStar
class contains three methods: say()
, sing()
, and dance()
.
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:96
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 are methods defined with the property
modifier declared at the end, such as:
fullName: Ember.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.
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.
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:139
To get the values of multiple properties at once, call getProperties
with a list of strings or an array:
record.getProperties('firstName', 'lastName', 'zipCode'); // { firstName: 'John', lastName: 'Doe', zipCode: '10011' }
is equivalent to:
record.getProperties(['firstName', 'lastName', 'zipCode']); // { firstName: 'John', lastName: 'Doe', zipCode: '10011' }
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:410
Retrieves the value of a property, or a default value in the case that the property returns undefined
.
person.getWithDefault('lastName', 'Doe');
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:428
Set the value of a property to the current value plus some amount.
person.incrementProperty('age'); team.incrementProperty('score', 2);
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:211
An overridable method called when objects are instantiated. By default, does nothing unless it is overridden during class definition.
Example:
const Person = Ember.Object.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.
Defined in packages/ember-application/lib/system/engine.js:175
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.Ember.Application.initializer({ name: 'namedInitializer', initialize: function(application) { Ember.debug('Running namedInitializer!'); } });
before
and after
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 the name
of other initializers.An example of ordering initializers, we create an initializer named first
:
Ember.Application.initializer({ name: 'first', initialize: function(application) { Ember.debug('First initializer!'); } }); // DEBUG: First initializer!
We add another initializer named second
, specifying that it should run after the initializer named first
:
Ember.Application.initializer({ name: 'second', after: 'first', initialize: function(application) { Ember.debug('Second initializer!'); } }); // 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
:
Ember.Application.initializer({ name: 'pre', before: 'first', initialize: function(application) { Ember.debug('Pre initializer!'); } }); // 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:
Ember.Application.initializer({ name: 'post', after: ['first', 'second'], initialize: function(application) { Ember.debug('Post initializer!'); } }); // 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:
Ember.Application.initializer({ name: 'api-adapter', initialize: function(application) { application.register('api-adapter:main', ApiAdapter); } });
Defined in packages/ember-application/lib/system/engine.js:295
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.Ember.Application.instanceInitializer({ name: 'namedinstanceInitializer', initialize: function(application) { Ember.debug('Running namedInitializer!'); } });
before
and after
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 the name
of other initializers.
See Ember.Application.initializer for discussion on the usage of before and after.
Example instanceInitializer to preload data into the store.
Ember.Application.initializer({ name: 'preload-data', initialize: function(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 = Ember.$('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); } });
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:318
Convenience method to call propertyWillChange
and propertyDidChange
in succession.
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:380
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.
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:715
Augments a constructor's prototype with additional properties and functions:
const MyObject = Ember.Object.extend({ name: 'an object' }); o = MyObject.create(); o.get('name'); // 'an object' MyObject.reopen({ say(msg) { console.log(msg); } }); o2 = MyObject.create(); o2.say('hello'); // logs "hello" o.say('goodbye'); // logs "goodbye"
To add functions and properties to the constructor itself, see reopenClass
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:751
Augments a constructor's own properties and functions:
const MyObject = Ember.Object.extend({ name: 'an object' }); MyObject.reopenClass({ canBuild: false }); MyObject.canBuild; // false o = MyObject.create();
In other words, this creates static properties and functions for the class. These are only available on the class and not on any instance of that class.
const Person = Ember.Object.extend({ name: '', sayHello() { alert(`Hello. My name is ${this.get('name')}`); } }); Person.reopenClass({ species: 'Homo sapiens', createPerson(name) { return Person.create({ name }); } }); let tom = Person.create({ name: 'Tom Dale' }); let yehuda = Person.createPerson('Yehuda Katz'); tom.sayHello(); // "Hello. My name is Tom Dale" yehuda.sayHello(); // "Hello. My name is Yehuda Katz" alert(Person.species); // "Homo sapiens"
Note that species
and createPerson
are not valid on the tom
and yehuda
variables. They are only valid on Person
.
To add functions and properties to instances of a constructor by extending the constructor's prototype see reopen
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:164
Sets the provided key or path to the value.
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.
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.
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.
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.
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:213
Sets a list of properties at once. These properties are set inside a single beginPropertyChanges
and endPropertyChanges
batch, so observers will be buffered.
record.setProperties({ firstName: 'Charles', lastName: 'Jolley' });
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:499
Returns a string representation which attempts to provide more information than Javascript's toString
typically does, in a generic way for all Ember objects.
const Person = Ember.Object.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:
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.
const Teacher = Person.extend({ toStringExtension() { return this.get('fullName'); } }); teacher = Teacher.create() teacher.toString(); //=> "<Teacher:ember1026:Tom Dale>"
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:468
Set the value of a boolean property to the opposite of its current value.
starship.toggleProperty('warpDriveEngaged');
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:472
Override to implement teardown.
© 2017 Yehuda Katz, Tom Dale and Ember.js contributors
Licensed under the MIT License.
https://emberjs.com/api/ember/2.15/classes/Ember.Engine/methods