Ember.LinkComponent Class packages/ember-routing-views/lib/components/link-to.js:330

Returns a jQuery object for this view's element. If you pass in a selector string, this method will return a jQuery object, using the current element as its buffer.

For example, calling view.$('li') will return a jQuery object containing all of the li elements inside the DOM element of this view.

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.

You can also pass an optional context parameter to this method. The context will be passed to your observer method whenever it is triggered. Note that if you add the same target/method pair on a key multiple times with different context parameters, your observer will only be called once with the last context you passed.

Observer Methods

Observer methods you pass should generally have the following signature if you do not pass a context parameter:

1

fooDidChange: function(sender, key, value, rev) { };

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.

If you pass a context parameter, the context will be passed before the revision like so:

1

fooDidChange: function(sender, key, value, context, rev) { };

Usually you will not need the value, context 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.

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.

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

1
2

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

Called when the attributes passed into the component have been updated. Called both during the initial render of a container and during a rerender. Can be used in place of an observer; code placed here will be executed every time any attribute updates.

Called after a component has been rendered, both on initial render and in subsequent rerenders.

Called when the attributes passed into the component have been changed. Called only during a rerender, not during an initial render.

Creates a new subclass.

1
2
3
4
5

App.Person = Ember.Object.extend({
  say: function(thing) {
    alert(thing);
   }
});

This defines a new subclass of Ember.Object: App.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.View class:

1
2
3
4

App.PersonView = Ember.View.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:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21

App.Person = Ember.Object.extend({
  say: function(thing) {
    var name = this.get('name');
    alert(name + ' says: ' + thing);
  }
});

App.Soldier = App.Person.extend({
  say: function(thing) {
    this._super(thing + ", sir!");
  },
  march: function(numberOfHours) {
    alert(this.get('name') + ' marches for ' + numberOfHours + ' hours.');
  }
});

var yehuda = App.Soldier.create({
  name: "Yehuda Katz"
});

yehuda.say("Yes");  // alerts "Yehuda Katz says: Yes, sir!"

The create() on line #17 creates an instance of the App.Soldier class. The extend() on line #8 creates a subclass of App.Person. Any instance of the App.Person class will not have the march() method.

You can also pass Mixin classes to add additional properties to the subclass.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

App.Person = Ember.Object.extend({
  say: function(thing) {
    alert(this.get('name') + ' says: ' + thing);
  }
});

App.SingingMixin = Mixin.create({
  sing: function(thing){
    alert(this.get('name') + ' sings: la la la ' + thing);
  }
});

App.BroadwayStar = App.Person.extend(App.SingingMixin, {
  dance: function() {
    alert(this.get('name') + ' dances: tap tap tap tap ');
  }
});

The App.BroadwayStar class contains three methods: say(), sing(), and dance().

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:

1
2
3

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

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

1
2

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

is equivalent to:

1
2

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

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

1

person.getWithDefault('lastName', 'Doe');

Checks to see if object has any subscriptions for named event.

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

1
2

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

Convenience method to call propertyWillChange and propertyDidChange in succession.

Cancels subscription for given name, target, and method.

Subscribes to a named event with given function.

1
2
3

person.on('didLoad', function() {
  // fired once the person has loaded
});

An optional target can be passed in as the 2nd argument that will be set as the "this" for the callback. This is a good way to give your function access to the object triggering the event. When the target parameter is used the callback becomes the third argument.

Subscribes a function to a named event and then cancels the subscription after the first time the event is triggered. It is good to use one when you only care about the first time an event has taken place.

This function takes an optional 2nd argument that will become the "this" value for the callback. If this argument is passed then the 3rd argument becomes the function.

Normally, Ember's component model is "write-only". The component takes a bunch of attributes that it got passed in, and uses them to render its template.

One nice thing about this model is that if you try to set a value to the same thing as last time, Ember (through HTMLBars) will avoid doing any work on the DOM.

This is not just a performance optimization. If an attribute has not changed, it is important not to clobber the element's "hidden state". For example, if you set an input's value to the same value as before, it will clobber selection state and cursor position. In other words, setting an attribute is not always idempotent.

This method provides a way to read an element's attribute and also update the last value Ember knows about at the same time. This makes setting an attribute idempotent.

In particular, what this means is that if you get an <input> element's value attribute and then re-render the template with the same value, it will avoid clobbering the cursor and selection position.

Since most attribute sets are idempotent in the browser, you typically can get away with reading attributes using jQuery, but the most reliable way to do so is through this method.

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.

Augments a constructor's own properties and functions:

1
2
3
4
5
6
7
8
9
10

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.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

App.Person = Ember.Object.extend({
  name : "",
  sayHello : function() {
    alert("Hello. My name is " + this.get('name'));
  }
});

App.Person.reopenClass({
  species : "Homo sapiens",
  createPerson: function(newPersonsName){
    return App.Person.create({
      name:newPersonsName
    });
  }
});

var tom = App.Person.create({
  name : "Tom Dale"
});
var yehuda = App.Person.createPerson("Yehuda Katz");

tom.sayHello(); // "Hello. My name is Tom Dale"
yehuda.sayHello(); // "Hello. My name is Yehuda Katz"
alert(App.Person.species); // "Homo sapiens"

Note that species and createPerson are not valid on the tom and yehuda variables. They are only valid on App.Person.

To add functions and properties to instances of a constructor by extending the constructor's prototype see reopen

Renders the view again. This will work regardless of whether the view is already in the DOM or not. If the view is in the DOM, the rendering process will be deferred to give bindings a chance to synchronize.

If children were added during the rendering process using appendChild, rerender will remove them, because they will be added again if needed by the next render.

In general, if the display of your view changes, you should modify the DOM element directly instead of manually calling rerender, which can be slow.

Triggers a named action on the ActionHandler. Any parameters supplied after the actionName string will be passed as arguments to the action target function.

If the ActionHandler has its target property set, actions may bubble to the target. Bubbling happens when an actionName can not be found in the ActionHandler's actions hash or if the action target function returns true.

Example

1
2
3
4
5
6
7
8
9
10

App.WelcomeRoute = Ember.Route.extend({
  actions: {
    playTheme: function() {
       this.send('playMusic', 'theme.mp3');
    },
    playMusic: function(track) {
      // ...
    }
  }
});

Calls a action passed to a component.

For example a component for playing or pausing music may translate click events into action notifications of "play" or "stop" depending on some internal state of the component:

1
2
3
4
5
6
7
8
9
10

// app/components/play-button.js
export default Ember.Component.extend({
  click() {
    if (this.get('isPlaying')) {
      this.sendAction('play');
    } else {
      this.sendAction('stop');
    }
  }
});

The actions "play" and "stop" must be passed to this play-button component:

1
2

{{! app/templates/application.hbs }}
{{play-button play=(action "musicStarted") stop=(action "musicStopped")}}

When the component receives a browser click event it translate this interaction into application-specific semantics ("play" or "stop") and calls the specified action.

1
2
3
4
5
6
7
8
9
10
11
12
13

// app/controller/application.js
export default Ember.Controller.extend({
  actions: {
    musicStarted() {
      // called when the play button is clicked
      // and the music started playing
    },
    musicStopped() {
      // called when the play button is clicked
      // and the music stopped playing
    }
  }
});

If no action is passed to sendAction a default name of "action" is assumed.

1
2
3
4
5
6

// app/components/next-button.js
export default Ember.Component.extend({
  click() {
    this.sendAction();
  }
});

1
2

{{! app/templates/application.hbs }}
{{next-button action=(action "playNextSongInAlbum")}}

1
2
3
4
5
6
7
8

// app/controllers/application.js
App.ApplicationController = Ember.Controller.extend({
  actions: {
    playNextSongInAlbum() {
      ...
    }
  }
});

Sets the provided key or path to the 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.

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

1

record.setProperties({ firstName: 'Charles', lastName: 'Jolley' });

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

1
2
3

App.Person = Em.Object.extend()
person = App.Person.create()
person.toString() //=> "<App.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:

1
2
3

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

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

1
2
3
4
5
6
7

App.Teacher = App.Person.extend({
  toStringExtension: function() {
    return this.get('fullName');
  }
});
teacher = App.Teacher.create()
teacher.toString(); //=> "<App.Teacher:ember1026:Tom Dale>"

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

1

starship.toggleProperty('warpDriveEngaged');

Override to implement teardown.

Called before a component has been rendered, both on initial render and in subsequent rerenders.

Called when the component is about to update and rerender itself. Called only during a rerender, not during an initial render.