Ember.Component Class packages/ember-htmlbars/lib/component.js:38


PUBLIC

An Ember.Component is a view that is completely isolated. Properties accessed in its templates go to the view object and actions are targeted at the view object. There is no access to the surrounding context or outer controller; all contextual information must be passed in.

The easiest way to create an Ember.Component is via a template. If you name a template components/my-foo, you will be able to use {{my-foo}} in other templates, which will make an instance of the isolated component.

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{{app-profile person=currentUser}}
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<!-- app-profile template -->
<h1>{{person.title}}</h1>
<img src={{person.avatar}}>
<p class='signature'>{{person.signature}}</p>

You can use yield inside a template to include the contents of any block attached to the component. The block will be executed in the context of the surrounding context or outer controller:

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{{#app-profile person=currentUser}}
  <p>Admin mode</p>
  {{! Executed in the controller's context. }}
{{/app-profile}}
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<!-- app-profile template -->
<h1>{{person.title}}</h1>
{{! Executed in the component's context. }}
{{yield}} {{! block contents }}

If you want to customize the component, in order to handle events or actions, you implement a subclass of Ember.Component named after the name of the component. Note that Component needs to be appended to the name of your subclass like AppProfileComponent.

For example, you could implement the action hello for the app-profile component:

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App.AppProfileComponent = Ember.Component.extend({
  actions: {
    hello: function(name) {
      console.log("Hello", name);
    }
  }
});

And then use it in the component's template:

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<!-- app-profile template -->

<h1>{{person.title}}</h1>
{{yield}} <!-- block contents -->

<button {{action 'hello' person.name}}>
  Say Hello to {{person.name}}
</button>

Components must have a - in their name to avoid conflicts with built-in controls that wrap HTML elements. This is consistent with the same requirement in web components.

Show:

$

(selector) JQuery public

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.

Parameters:

selector [String]
a jQuery-compatible selector string

Returns:

JQuery
the jQuery object for the DOM node

_classStringForProperty

(property) private

Given a property name, returns a dasherized version of that property name if the property evaluates to a non-falsy value.

For example, if the view has property isUrgent that evaluates to true, passing isUrgent to this method will return "is-urgent".

Parameters:

property

_isVisibleDidChange

private

When the view's isVisible property changes, toggle the visibility element of the actual DOM element.

_lazyInjections

Object private

Returns a hash of property names and container names that injected properties will lookup on the container lazily.

Returns:

Object
Hash of all lazy injected property keys to container names

_onLookup

private

Provides lookup-time type validation for injected properties.

_register

private

Registers the view in the view registry, keyed on the view's elementId. This is used by the EventDispatcher to locate the view in response to events.

This method should only be called once the view has been inserted into the DOM.

_scheduledDestroy

private

Invoked by the run loop to actually destroy the object. This is scheduled for execution by the destroy method.

_unregister

private

Removes the view from the view registry. This should be called when the view is removed from DOM.

addObserver

(key, target, method) public

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:

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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:

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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.

Parameters:

key String
The key to observer
target Object
The target object to invoke
method String|Function
The method to invoke.

append

Ember.View private

Appends the view's element to the document body. If the view does not have an HTML representation yet the element will be generated automatically.

If your application uses the rootElement property, you must append the view within that element. Rendering views outside of the rootElement is not supported.

Note that this method just schedules the view to be appended; the DOM element will not be appended to the document body until all bindings have finished synchronizing.

Returns:

Ember.View
receiver

appendTo

(A) Ember.View private

Appends the view's element to the specified parent element.

If the view does not have an HTML representation yet, createElement() will be called automatically.

Note that this method just schedules the view to be appended; the DOM element will not be appended to the given element until all bindings have finished synchronizing.

This is not typically a function that you will need to call directly when building your application. If you do need to use appendTo, be sure that the target element you are providing is associated with an Ember.Application and does not have an ancestor element that is associated with an Ember view.

Parameters:

A String|DOMElement|jQuery
selector, element, HTML string, or jQuery object

Returns:

Ember.View
receiver

apply

(obj) private

Parameters:

obj

Returns:

applied object

beginPropertyChanges

Ember.Observable private

Begins a grouping of property changes.

You can use this method to group property changes so that notifications will not be sent until the changes are finished. If you plan to make a large number of changes to an object at one time, you should call this method at the beginning of the changes to begin deferring change notifications. When you are done making changes, call endPropertyChanges() to deliver the deferred change notifications and end deferring.

Returns:

Ember.Observable

cacheFor

(keyName) Object public

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.

Parameters:

keyName String

Returns:

Object
The cached value of the computed property, if any

create

(arguments) public static
Inherited from Ember.CoreObject but overwritten in packages/ember-metal/lib/mixin.js:499

Parameters:

arguments

createChildView

(viewClass, attrs) Ember.View private

Instantiates a view to be added to the childViews array during view initialization. You generally will not call this method directly unless you are overriding createChildViews(). Note that this method will automatically configure the correct settings on the new view instance to act as a child of the parent.

Parameters:

viewClass Class|String
attrs [Object]
Attributes to add

Returns:

Ember.View
new instance

createElement

Ember.View private

Creates a DOM representation of the view and all of its child views by recursively calling the render() method. Once the element is created, it sets the element property of the view to the rendered element.

After the element has been inserted into the DOM, didInsertElement will be called on this view and all of its child views.

Returns:

Ember.View
receiver

decrementProperty

(keyName, decrement) Number public

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

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

Parameters:

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

destroy

private

You must call destroy on a view to destroy the view (and all of its child views). This will remove the view from any parent node, then make sure that the DOM element managed by the view can be released by the memory manager.

destroyElement

Ember.View private

Destroys any existing element along with the element for any child views as well. If the view does not currently have a element, then this method will do nothing.

If you implement willDestroyElement() on your view, then this method will be invoked on your view before your element is destroyed to give you a chance to clean up any event handlers, etc.

If you write a willDestroyElement() handler, you can assume that your didInsertElement() handler was called earlier for the same element.

You should not call or override this method yourself, but you may want to implement the above callbacks.

Returns:

Ember.View
receiver

detect

(obj) Boolean private

Parameters:

obj

Returns:

Boolean

didReceiveAttrs

public
Defined in packages/ember-htmlbars/lib/component.js:487
Available since 1.13.0

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.

didRender

public
Defined in packages/ember-htmlbars/lib/component.js:509
Available since 1.13.0

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

didUpdateAttrs

public
Defined in packages/ember-htmlbars/lib/component.js:545
Available since 1.13.0

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

eachComputedProperty

(callback, binding) private static

Iterate over each computed property for the class, passing its name and any associated metadata (see metaForProperty) to the callback.

Parameters:

callback Function
binding Object

endPropertyChanges

Ember.Observable private

Ends a grouping of property changes.

You can use this method to group property changes so that notifications will not be sent until the changes are finished. If you plan to make a large number of changes to an object at one time, you should call beginPropertyChanges() at the beginning of the changes to defer change notifications. When you are done making changes, call this method to deliver the deferred change notifications and end deferring.

Returns:

Ember.Observable

extend

(mixins, arguments) public static

Creates a new subclass.

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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:

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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:

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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.

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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().

Parameters:

mixins [Mixin]
One or more Mixin classes
arguments [Object]
Object containing values to use within the new class

findElementInParentElement

(parentElement) DOMElement private

Attempts to discover the element in the parent element. The default implementation looks for an element with an ID of elementId (or the view's guid if elementId is null). You can override this method to provide your own form of lookup. For example, if you want to discover your element using a CSS class name instead of an ID.

Parameters:

parentElement DOMElement
The parent's DOM element

Returns:

DOMElement
The discovered element

get

(keyName) Object public

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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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.

Parameters:

keyName String
The property to retrieve

Returns:

Object
The property value or undefined.

getProperties

(list) Object public

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' }

Parameters:

list String...|Array
of keys to get

Returns:

Object

getViewBoundingClientRect

(view) private

getViewBoundingClientRect provides information about the position of the bounding border box edges of a view relative to the viewport.

It is only intended to be used by development tools like the Ember Inpsector and may not work on older browsers.

Parameters:

view Ember.View

getViewClientRects

(view) private

getViewClientRects provides information about the position of the border box edges of a view relative to the viewport.

It is only intended to be used by development tools like the Ember Inspector and may not work on older browsers.

Parameters:

view Ember.View

getViewRange

(view) private

Parameters:

view Ember.View

getWithDefault

(keyName, defaultValue) Object public

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');

Parameters:

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.

handleEvent

(eventName, evt) private

Handle events from Ember.EventDispatcher

Parameters:

eventName String
evt Event

has

(name) Boolean public

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

Parameters:

name String
The name of the event

Returns:

Boolean
does the object have a subscription for event

hasObserverFor

(key) Boolean private

Returns true if the object currently has observers registered for a particular key. You can use this method to potentially defer performing an expensive action until someone begins observing a particular property on the object.

Parameters:

key String
Key to check

Returns:

Boolean

incrementProperty

(keyName, increment) Number public

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

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

Parameters:

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

init

private

Setup a view, but do not finish waking it up.

  • configure childViews
  • register the view with the global views hash, which is used for event dispatch

metaForProperty

(key) private static

In some cases, you may want to annotate computed properties with additional metadata about how they function or what values they operate on. For example, computed property functions may close over variables that are then no longer available for introspection.

You can pass a hash of these values to a computed property like this:

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person: function() {
  var personId = this.get('personId');
  return App.Person.create({ id: personId });
}.property().meta({ type: App.Person })

Once you've done this, you can retrieve the values saved to the computed property from your class like this:

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MyClass.metaForProperty('person');

This will return the original hash that was passed to meta().

Parameters:

key String
property name

nearestChildOf

(klass) deprecated private

Return the nearest ancestor whose parent is an instance of klass.

Parameters:

klass Class
Subclass of Ember.View (or Ember.View itself)

Returns:

Ember.View

nearestInstanceOf

(klass) deprecated private

Return the nearest ancestor that is an instance of the provided class.

Parameters:

klass Class
Subclass of Ember.View (or Ember.View itself)

Returns:

Ember.View

nearestOfType

(klass) private

Return the nearest ancestor that is an instance of the provided class or mixin.

Parameters:

klass Class,Mixin
Subclass of Ember.View (or Ember.View itself), or an instance of Ember.Mixin.

Returns:

Ember.View

nearestWithProperty

(property) private

Return the nearest ancestor that has a given property.

Parameters:

property String
A property name

Returns:

Ember.View

notifyPropertyChange

(keyName) Ember.Observable public

Convenience method to call propertyWillChange and propertyDidChange in succession.

Parameters:

keyName String
The property key to be notified about.

Returns:

Ember.Observable

off

(name, target, method) public

Cancels subscription for given name, target, and method.

Parameters:

name String
The name of the event
target Object
The target of the subscription
method Function
The function of the subscription

Returns:

this

on

(name, target, method) public

Subscribes to a named event with given function.

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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.

Parameters:

name String
The name of the event
target [Object]
The "this" binding for the callback
method Function
The callback to execute

Returns:

this

one

(name, target, method) public

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.

Parameters:

name String
The name of the event
target [Object]
The "this" binding for the callback
method Function
The callback to execute

Returns:

this

propertyDidChange

(keyName) Ember.Observable private

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 and propertyWillChange() instead. Calling these two methods together will notify all observers that the property has potentially changed value.

Note that you must always call propertyWillChange and propertyDidChange as a pair. If you do not, it may get the property change groups out of order and cause notifications to be delivered more often than you would like.

Parameters:

keyName String
The property key that has just changed.

Returns:

Ember.Observable

propertyWillChange

(keyName) Ember.Observable private

Notify the observer system that a property is about to change.

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 and propertyDidChange() instead. Calling these two methods together will notify all observers that the property has potentially changed value.

Note that you must always call propertyWillChange and propertyDidChange as a pair. If you do not, it may get the property change groups out of order and cause notifications to be delivered more often than you would like.

Parameters:

keyName String
The property key that is about to change.

Returns:

Ember.Observable

readDOMAttr

(name) public

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.

Parameters:

name String
the name of the attribute

Returns:

String

remove

Ember.View private

Removes the view's element from the element to which it is attached.

Returns:

Ember.View
receiver

removeChild

(view) Ember.View private

Removes the child view from the parent view.

Parameters:

view Ember.View

Returns:

Ember.View
receiver

removeFromParent

Ember.View private

Removes the view from its parentView, if one is found. Otherwise does nothing.

Returns:

Ember.View
receiver

removeObserver

(key, target, method) public

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.

Parameters:

key String
The key to observer
target Object
The target object to invoke
method String|Function
The method to invoke.

renderToElement

(tagName) HTMLBodyElement private

Creates a new DOM element, renders the view into it, then returns the element.

By default, the element created and rendered into will be a BODY element, since this is the default context that views are rendered into when being inserted directly into the DOM.

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var element = view.renderToElement();
element.tagName; // => "BODY"

You can override the kind of element rendered into and returned by specifying an optional tag name as the first argument.

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var element = view.renderToElement('table');
element.tagName; // => "TABLE"

This method is useful if you want to render the view into an element that is not in the document's body. Instead, a new body element, detached from the DOM is returned. FastBoot uses this to serialize the rendered view into a string for transmission over the network.

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app.visit('/').then(function(instance) {
  var element;
  Ember.run(function() {
    element = renderToElement(instance);
  });

  res.send(serialize(element));
});

Parameters:

tagName String
The tag of the element to create and render into. Defaults to "body".

Returns:

HTMLBodyElement
element

reopen

(arguments) private
Inherited from Ember.CoreObject but overwritten in packages/ember-metal/lib/mixin.js:515

Parameters:

arguments

reopenClass

public

Augments a constructor's own properties and functions:

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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.

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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

replaceIn

(target) Ember.View private

Replaces the content of the specified parent element with this view's element. If the view does not have an HTML representation yet, the element will be generated automatically.

Note that this method just schedules the view to be appended; the DOM element will not be appended to the given element until all bindings have finished synchronizing

Parameters:

target String|DOMElement|jQuery
A selector, element, HTML string, or jQuery object

Returns:

Ember.View
received

rerender

public

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.

send

(actionName, context) public

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

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

Parameters:

actionName String
The action to trigger
context *
a context to send with the action

sendAction

(action, params) public

Calls an 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:

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// 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:

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{{! 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.

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// 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.

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// app/components/next-button.js
export default Ember.Component.extend({
  click() {
    this.sendAction();
  }
});
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{{! app/templates/application.hbs }}
{{next-button action=(action "playNextSongInAlbum")}}
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// app/controllers/application.js
App.ApplicationController = Ember.Controller.extend({
  actions: {
    playNextSongInAlbum() {
      ...
    }
  }
});

Parameters:

action [String]
the action to call
params [*]
arguments for the action

set

(keyName, value) Object public

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.

Parameters:

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

Returns:

Object
The passed value

setProperties

(hash) Object public

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' });

Parameters:

hash Object
the hash of keys and values to set

Returns:

Object
The passed in hash

toString

String public

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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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:

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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.

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

Returns:

String
string representation

toggleProperty

(keyName) Boolean public

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

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Parameters:

keyName String
The name of the property to toggle

Returns:

Boolean
The new property value

trigger

(name) private

Override the default event firing from Ember.Evented to also call methods with the given name.

Parameters:

name String

triggerAction

(opts) Boolean private

Send an action with an actionContext to a target. The action, actionContext and target will be retrieved from properties of the object. For example:

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App.SaveButtonView = Ember.View.extend(Ember.TargetActionSupport, {
  target: Ember.computed.alias('controller'),
  action: 'save',
  actionContext: Ember.computed.alias('context'),
  click: function() {
    this.triggerAction(); // Sends the `save` action, along with the current context
                          // to the current controller
  }
});

The target, action, and actionContext can be provided as properties of an optional object argument to triggerAction as well.

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App.SaveButtonView = Ember.View.extend(Ember.TargetActionSupport, {
  click: function() {
    this.triggerAction({
      action: 'save',
      target: this.get('controller'),
      actionContext: this.get('context')
    }); // Sends the `save` action, along with the current context
        // to the current controller
  }
});

The actionContext defaults to the object you are mixing TargetActionSupport into. But target and action must be specified either as properties or with the argument to triggerAction, or a combination:

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App.SaveButtonView = Ember.View.extend(Ember.TargetActionSupport, {
  target: Ember.computed.alias('controller'),
  click: function() {
    this.triggerAction({
      action: 'save'
    }); // Sends the `save` action, along with a reference to `this`,
        // to the current controller
  }
});

Parameters:

opts Object
(optional, with the optional keys action, target and/or actionContext)

Returns:

Boolean
true if the action was sent successfully and did not return false

willDestroy

public

Override to implement teardown.

willRender

public
Defined in packages/ember-htmlbars/lib/component.js:527
Available since 1.13.0

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

willUpdate

public
Defined in packages/ember-htmlbars/lib/component.js:563
Available since 1.13.0

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

Show:

_context

private

Private copy of the view's template context. This can be set directly by Handlebars without triggering the observer that causes the view to be re-rendered.

The context of a view is looked up as follows:

  1. Supplied context (usually by Handlebars)
  2. Specified controller
  3. parentView's context

The code in Handlebars that overrides the _context property first checks to see whether the view has a specified controller. This is something of a hack and should be revisited.

actionContext

private

actions

Object public

The collection of functions, keyed by name, available on this ActionHandler as action targets.

These functions will be invoked when a matching {{action}} is triggered from within a template and the application's current route is this route.

Actions can also be invoked from other parts of your application via ActionHandler#send.

The actions hash will inherit action handlers from the actions hash defined on extended parent classes or mixins rather than just replace the entire hash, e.g.:

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App.CanDisplayBanner = Ember.Mixin.create({
  actions: {
    displayBanner: function(msg) {
      // ...
    }
  }
});

App.WelcomeRoute = Ember.Route.extend(App.CanDisplayBanner, {
  actions: {
    playMusic: function() {
      // ...
    }
  }
});

// `WelcomeRoute`, when active, will be able to respond
// to both actions, since the actions hash is merged rather
// then replaced when extending mixins / parent classes.
this.send('displayBanner');
this.send('playMusic');

Within a Controller, Route, View or Component's action handler, the value of the this context is the Controller, Route, View or Component object:

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App.SongRoute = Ember.Route.extend({
  actions: {
    myAction: function() {
      this.controllerFor("song");
      this.transitionTo("other.route");
      ...
    }
  }
});

It is also possible to call this._super(...arguments) from within an action handler if it overrides a handler defined on a parent class or mixin:

Take for example the following routes:

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App.DebugRoute = Ember.Mixin.create({
  actions: {
    debugRouteInformation: function() {
      console.debug("trololo");
    }
  }
});

App.AnnoyingDebugRoute = Ember.Route.extend(App.DebugRoute, {
  actions: {
    debugRouteInformation: function() {
      // also call the debugRouteInformation of mixed in App.DebugRoute
      this._super(...arguments);

      // show additional annoyance
      window.alert(...);
    }
  }
});

Bubbling

By default, an action will stop bubbling once a handler defined on the actions hash handles it. To continue bubbling the action, you must return true from the handler:

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App.Router.map(function() {
  this.route("album", function() {
    this.route("song");
  });
});

App.AlbumRoute = Ember.Route.extend({
  actions: {
    startPlaying: function() {
    }
  }
});

App.AlbumSongRoute = Ember.Route.extend({
  actions: {
    startPlaying: function() {
      // ...

      if (actionShouldAlsoBeTriggeredOnParentRoute) {
        return true;
      }
    }
  }
});

Default: null

ariaRole

String public

The WAI-ARIA role of the control represented by this view. For example, a button may have a role of type 'button', or a pane may have a role of type 'alertdialog'. This property is used by assistive software to help visually challenged users navigate rich web applications.

The full list of valid WAI-ARIA roles is available at: http://www.w3.org/TR/wai-aria/roles#roles_categorization

Default: null

childViews

Array private

Array of child views. You should never edit this array directly.

Default: []

classNameBindings

Array public

A list of properties of the view to apply as class names. If the property is a string value, the value of that string will be applied as a class name.

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// Applies the 'high' class to the view element
Ember.View.extend({
  classNameBindings: ['priority'],
  priority: 'high'
});

If the value of the property is a Boolean, the name of that property is added as a dasherized class name.

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// Applies the 'is-urgent' class to the view element
Ember.View.extend({
  classNameBindings: ['isUrgent'],
  isUrgent: true
});

If you would prefer to use a custom value instead of the dasherized property name, you can pass a binding like this:

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// Applies the 'urgent' class to the view element
Ember.View.extend({
  classNameBindings: ['isUrgent:urgent'],
  isUrgent: true
});

This list of properties is inherited from the view's superclasses as well.

Default: []

classNames

Array public

Standard CSS class names to apply to the view's outer element. This property automatically inherits any class names defined by the view's superclasses as well.

Default: ['ember-view']

concatenatedProperties

Array public

Defines the properties that will be concatenated from the superclass (instead of overridden).

By default, when you extend an Ember class a property defined in the subclass overrides a property with the same name that is defined in the superclass. However, there are some cases where it is preferable to build up a property's value by combining the superclass' property value with the subclass' value. An example of this in use within Ember is the classNames property of Ember.View.

Here is some sample code showing the difference between a concatenated property and a normal one:

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App.BarView = Ember.View.extend({
  someNonConcatenatedProperty: ['bar'],
  classNames: ['bar']
});

App.FooBarView = App.BarView.extend({
  someNonConcatenatedProperty: ['foo'],
  classNames: ['foo']
});

var fooBarView = App.FooBarView.create();
fooBarView.get('someNonConcatenatedProperty'); // ['foo']
fooBarView.get('classNames'); // ['ember-view', 'bar', 'foo']

This behavior extends to object creation as well. Continuing the above example:

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var view = App.FooBarView.create({
  someNonConcatenatedProperty: ['baz'],
  classNames: ['baz']
})
view.get('someNonConcatenatedProperty'); // ['baz']
view.get('classNames'); // ['ember-view', 'bar', 'foo', 'baz']

Adding a single property that is not an array will just add it in the array:

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var view = App.FooBarView.create({
  classNames: 'baz'
})
view.get('classNames'); // ['ember-view', 'bar', 'foo', 'baz']

Using the concatenatedProperties property, we can tell Ember to mix the content of the properties.

In Ember.View the classNameBindings and attributeBindings properties are also concatenated, in addition to classNames.

This feature is available for you to use throughout the Ember object model, although typical app developers are likely to use it infrequently. Since it changes expectations about behavior of properties, you should properly document its usage in each individual concatenated property (to not mislead your users to think they can override the property in a subclass).

Default: null

context

Object private

The object from which templates should access properties.

This object will be passed to the template function each time the render method is called, but it is up to the individual function to decide what to do with it.

By default, this will be the view's controller.

controller

Object private

The controller managing this view. If this property is set, it will be made available for use by the template.

element

DOMElement public

Returns the current DOM element for the view.

elementId

String public

The HTML id of the view's element in the DOM. You can provide this value yourself but it must be unique (just as in HTML):

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  {{my-component elementId="a-really-cool-id"}}

If not manually set a default value will be provided by the framework.

Once rendered an element's elementId is considered immutable and you should never change it. If you need to compute a dynamic value for the elementId, you should do this when the component or element is being instantiated:

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  export default Ember.Component.extend({
    setElementId: Ember.on('init', function() {
      var index = this.get('index');
      this.set('elementId', 'component-id' + index);
    })
  });

hasBlock

public
Defined in packages/ember-htmlbars/lib/component.js:333
Available since 1.13.0

Returns true when the component was invoked with a block template.

Example (hasBlock will be false):

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{{! templates/application.hbs }}

{{foo-bar}}

{{! templates/components/foo-bar.hbs }}
{{#if hasBlock}}
  This will not be printed, because no block was provided
{{/if}}

Example (hasBlock will be true):

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{{! templates/application.hbs }}

{{#foo-bar}}
  Hi!
{{/foo-bar}}

{{! templates/components/foo-bar.hbs }}
{{#if hasBlock}}
  This will be printed because a block was provided
  {{yield}}
{{/if}}

This helper accepts an argument with the name of the block we want to check the presence of. This is useful for checking for the presence of the optional inverse block in components.

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{{! templates/application.hbs }}

{{#foo-bar}}
  Hi!
{{else}}
  What's up?
{{/foo-bar}}

{{! templates/components/foo-bar.hbs }}
{{yield}}
{{#if (hasBlock "inverse")}}
  {{yield to="inverse"}}
{{else}}
  How are you?
{{/if}}

Returns:

Boolean

hasBlockParams

public
Defined in packages/ember-htmlbars/lib/component.js:393
Available since 1.13.0

Returns true when the component was invoked with a block parameter supplied.

Example (hasBlockParams will be false):

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{{! templates/application.hbs }}

{{#foo-bar}}
  No block parameter.
{{/foo-bar}}

{{! templates/components/foo-bar.hbs }}
{{#if hasBlockParams}}
  This will not be printed, because no block was provided
  {{yield this}}
{{/if}}

Example (hasBlockParams will be true):

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{{! templates/application.hbs }}

{{#foo-bar as |foo|}}
  Hi!
{{/foo-bar}}

{{! templates/components/foo-bar.hbs }}
{{#if hasBlockParams}}
  This will be printed because a block was provided
  {{yield this}}
{{/if}}

Returns:

Boolean

instrumentDisplay

String public

Used to identify this view during debugging

isDestroyed

public

Destroyed object property flag.

if this property is true the observers and bindings were already removed by the effect of calling the destroy() method.

Default: false

isDestroying

public

Destruction scheduled flag. The destroy() method has been called.

The object stays intact until the end of the run loop at which point the isDestroyed flag is set.

Default: false

isView

Boolean private static

Default: true

isVisible

Boolean public

If false, the view will appear hidden in DOM.

Default: null

layout

Function private

A view may contain a layout. A layout is a regular template but supersedes the template property during rendering. It is the responsibility of the layout template to retrieve the template property from the view (or alternatively, call Handlebars.helpers.yield, {{yield}}) to render it in the correct location.

This is useful for a view that has a shared wrapper, but which delegates the rendering of the contents of the wrapper to the template property on a subclass.

layoutName

String private

The name of the layout to lookup if no layout is provided.

By default Ember.View will lookup a template with this name in Ember.TEMPLATES (a shared global object).

Default: null

mergedProperties

Array public

Defines the properties that will be merged from the superclass (instead of overridden).

By default, when you extend an Ember class a property defined in the subclass overrides a property with the same name that is defined in the superclass. However, there are some cases where it is preferable to build up a property's value by merging the superclass property value with the subclass property's value. An example of this in use within Ember is the queryParams property of routes.

Here is some sample code showing the difference between a merged property and a normal one:

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App.BarRoute = Ember.Route.extend({
  someNonMergedProperty: {
    nonMerged: 'superclass value of nonMerged'
  },
  queryParams: {
    page: {replace: false},
    limit: {replace: true}
  }
});

App.FooBarRoute = App.BarRoute.extend({
  someNonMergedProperty: {
    completelyNonMerged: 'subclass value of nonMerged'
  },
  queryParams: {
    limit: {replace: false}
  }
});

var fooBarRoute = App.FooBarRoute.create();

fooBarRoute.get('someNonMergedProperty');
// => { completelyNonMerged: 'subclass value of nonMerged' }
//
// Note the entire object, including the nonMerged property of
// the superclass object, has been replaced

fooBarRoute.get('queryParams');
// => {
//   page: {replace: false},
//   limit: {replace: false}
// }
//
// Note the page remains from the superclass, and the
// `limit` property's value of `false` has been merged from
// the subclass.

This behavior is not available during object create calls. It is only available at extend time.

This feature is available for you to use throughout the Ember object model, although typical app developers are likely to use it infrequently. Since it changes expectations about behavior of properties, you should properly document its usage in each individual merged property (to not mislead your users to think they can override the property in a subclass).

Default: null

parentView

Ember.View private

If the view is currently inserted into the DOM of a parent view, this property will point to the parent of the view.

Default: null

positionalParams

public static
Defined in packages/ember-htmlbars/lib/component.js:434
Available since 1.13.0

Enables components to take a list of parameters as arguments.

For example, a component that takes two parameters with the names name and age:

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let MyComponent = Ember.Component.extend;
MyComponent.reopenClass({
  positionalParams: ['name', 'age']
});

It can then be invoked like this:

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{{my-component "John" 38}}

The parameters can be referred to just like named parameters:

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Name: {{attrs.name}}, Age: {{attrs.age}}.

Using a string instead of an array allows for an arbitrary number of parameters:

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let MyComponent = Ember.Component.extend;
MyComponent.reopenClass({
  positionalParams: 'names'
});

It can then be invoked like this:

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{{my-component "John" "Michael" "Scott"}}

The parameters can then be referred to by enumerating over the list:

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{{#each attrs.names as |name|}}{{name}}{{/each}}

tagName

String public

Tag name for the view's outer element. The tag name is only used when an element is first created. If you change the tagName for an element, you must destroy and recreate the view element.

By default, the render buffer will use a <div> tag for views.

Default: null

target

private

targetObject

Ember.Controller private

If the component is currently inserted into the DOM of a parent view, this property will point to the controller of the parent view.

Default: null

template

Function private

The template used to render the view. This should be a function that accepts an optional context parameter and returns a string of HTML that will be inserted into the DOM relative to its parent view.

In general, you should set the templateName property instead of setting the template yourself.

templateName

String private

The name of the template to lookup if no template is provided.

By default Ember.View will lookup a template with this name in Ember.TEMPLATES (a shared global object).

Default: null

views

Object private static

Global views hash

Show:

didInsertElement

public

Called when the element of the view has been inserted into the DOM or after the view was re-rendered. Override this function to do any set up that requires an element in the document body.

When a view has children, didInsertElement will be called on the child view(s) first, bubbling upwards through the hierarchy.

didReceiveAttrs

public
Defined in packages/ember-htmlbars/lib/component.js:498
Available since 1.13.0

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.

didRender

public
Defined in packages/ember-htmlbars/lib/component.js:518
Available since 1.13.0

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

didUpdate

public
Inherited from Ember.Component but overwritten in packages/ember-htmlbars/lib/component.js:590
Available since 1.13.0

Called when the component has updated and rerendered itself. Called only during a rerender, not during an initial render.

didUpdateAttrs

public
Defined in packages/ember-htmlbars/lib/component.js:554
Available since 1.13.0

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

parentViewDidChange

private

Called when the parentView property has changed.

willClearRender

public

Called when the view is about to rerender, but before anything has been torn down. This is a good opportunity to tear down any manual observers you have installed based on the DOM state

willDestroyElement

public

Called when the element of the view is going to be destroyed. Override this function to do any teardown that requires an element, like removing event listeners.

Please note: any property changes made during this event will have no effect on object observers.

willInsertElement

public

Called when a view is going to insert an element into the DOM.

willRender

public
Defined in packages/ember-htmlbars/lib/component.js:536
Available since 1.13.0

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

willUpdate

public
Defined in packages/ember-htmlbars/lib/component.js:572
Available since 1.13.0

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