class SampleView extends View {
	constructor() {
		super();

		// A template instance the #element will be created from.
		this.setTemplate( {
			tag: 'p'

			// ...
		} );
	}
}

const view = new SampleView();

// Renders the #template.
view.render();

// Append the HTML element of the view to <body>.
document.body.appendChild( view.element );

Note: The element of the view can also be assigned directly:

view.element = document.querySelector( '#my-container' );

readonly inherited
isRendered : Boolean

See source
Set true when the view has already been rendered.
readonly inherited
locale : Locale

See source
A set of tools to localize the user interface.

Also see locale.
inherited
template : Template

See source
Template of this view. It provides the element representing the view in DOM, which is rendered.
protected inherited
_unboundChildren : ViewCollection

See source
A collection of view instances, which have been added directly into the children.
protected inherited
_viewCollections : Set.<ViewCollection>

See source
Collections registered with createCollection.
private inherited
_bindTemplate : Object

See source
Cached bind chain object created by the template. See bindTemplate.

Methods

inherited
constructor( [ locale ] )

See source
Creates an instance of the View class.

Also see render.

Parameters

[ locale ] : Locale

The localization services instance.
mixed
bind( bindProperties ) → Object
See source
Binds observable properties to other objects implementing the Observable interface.

Read more in the dedicated guide covering the topic of property bindings with some additional examples.

Consider two objects: a button and an associated command (both Observable).

A simple property binding could be as follows:
```
button.bind( 'isEnabled' ).to( command, 'isEnabled' );
```
or even shorter:
```
button.bind( 'isEnabled' ).to( command );
```
which works in the following way:
- button.isEnabled instantly equals command.isEnabled,
- whenever command.isEnabled changes, button.isEnabled will immediately reflect its value.
Note: To release the binding, use unbind.

You can also "rename" the property in the binding by specifying the new name in the to() chain:
```
button.bind( 'isEnabled' ).to( command, 'isWorking' );
```
It is possible to bind more than one property at a time to shorten the code:
```
button.bind( 'isEnabled', 'value' ).to( command );
```
which corresponds to:
```
button.bind( 'isEnabled' ).to( command );
button.bind( 'value' ).to( command );
```
The binding can include more than one observable, combining multiple data sources in a custom callback:
```
button.bind( 'isEnabled' ).to( command, 'isEnabled', ui, 'isVisible',
	( isCommandEnabled, isUIVisible ) => isCommandEnabled && isUIVisible );
```
Using a custom callback allows processing the value before passing it to the target property:
```
button.bind( 'isEnabled' ).to( command, 'value', value => value === 'heading1' );
```
It is also possible to bind to the same property in an array of observables. To bind a button to multiple commands (also Observables) so that each and every one of them must be enabled for the button to become enabled, use the following code:
```
button.bind( 'isEnabled' ).toMany( [ commandA, commandB, commandC ], 'isEnabled',
	( isAEnabled, isBEnabled, isCEnabled ) => isAEnabled && isBEnabled && isCEnabled );
```
Parameters

bindProperties : String

Observable properties that will be bound to other observable(s).

Returns

Object

The bind chain with the to() and toMany() methods.

inherited
`bindTemplate()`

See source

Shorthand for bind, a binding interface pre–configured for the view instance.

It provides to() and if() methods that initialize bindings with observable attributes and attach DOM listeners.

class SampleView extends View {
	constructor( locale ) {
		super( locale );

		const bind = this.bindTemplate;

		// These observable attributes will control
		// the state of the view in DOM.
		this.set( {
			elementClass: 'foo',
		 	isEnabled: true
		 } );

		this.setTemplate( {
			tag: 'p',

			attributes: {
				// The class HTML attribute will follow elementClass
				// and isEnabled view attributes.
				class: [
					bind.to( 'elementClass' )
					bind.if( 'isEnabled', 'present-when-enabled' )
				]
			},

			on: {
				// The view will fire the "clicked" event upon clicking <p> in DOM.
				click: bind.to( 'clicked' )
			}
		} );
	}
}

inherited
`createCollection( [ views ] ) → ViewCollection`

See source

Creates a new collection of views, which can be used as children of this view.

class SampleView extends View {
	constructor( locale ) {
		super( locale );

		const child = new ChildView( locale );
		this.items = this.createCollection( [ child ] );

		this.setTemplate( {
			tag: 'p',

			// `items` collection will render here.
			children: this.items
		} );
	}
}

const view = new SampleView( locale );
view.render();

// It will append <p><child#element></p> to the <body>.
document.body.appendChild( view.element );

Parameters

[ views ] : Iterable.<View>: Initial views of the collection.

Returns

ViewCollection: A new collection of view instances.

mixed
decorate( methodName )
See source
Turns the given methods of this object into event-based ones. This means that the new method will fire an event (named after the method) and the original action will be plugged as a listener to that event.

Read more in the dedicated guide covering the topic of decorating methods with some additional examples.

Decorating the method does not change its behavior (it only adds an event), but it allows to modify it later on by listening to the method's event.

For example, to cancel the method execution the event can be stopped:
```
class Foo {
	constructor() {
		this.decorate( 'method' );
	}

	method() {
		console.log( 'called!' );
	}
}

const foo = new Foo();
foo.on( 'method', ( evt ) => {
	evt.stop();
}, { priority: 'high' } );

foo.method(); // Nothing is logged.
```
Note: The high priority listener has been used to execute this particular callback before the one which calls the original method (which uses the "normal" priority).

It is also possible to change the returned value:
```
foo.on( 'method', ( evt ) => {
	evt.return = 'Foo!';
} );

foo.method(); // -> 'Foo'
```
Finally, it is possible to access and modify the arguments the method is called with:
```
method( a, b ) {
	console.log( `${ a }, ${ b }`  );
}

// ...

foo.on( 'method', ( evt, args ) => {
	args[ 0 ] = 3;

	console.log( args[ 1 ] ); // -> 2
}, { priority: 'high' } );

foo.method( 1, 2 ); // -> '3, 2'
```
Parameters

methodName : String

Name of the method to decorate.
mixed
delegate( events ) → EmitterMixinDelegateChain
See source
Delegates selected events to another Emitter. For instance:
```
emitterA.delegate( 'eventX' ).to( emitterB );
emitterA.delegate( 'eventX', 'eventY' ).to( emitterC );
```
then eventX is delegated (fired by) emitterB and emitterC along with data:
```
emitterA.fire( 'eventX', data );
```
and eventY is delegated (fired by) emitterC along with data:
```
emitterA.fire( 'eventY', data );
```
Parameters

events : String

Event names that will be delegated to another emitter.

Returns

EmitterMixinDelegateChain
inherited
deregisterChild( children )
See source
The opposite of registerChild. Removes a child view from this view instance. Once removed, the child is no longer managed by its parent, e.g. it can safely become a child of another parent view.

Parameters

children : View | Iterable.<View>

Child views to be removed.

Related:
- View#registerChild
inherited
destroy()
See source
Recursively destroys the view instance and child views added by registerChild and residing in collections created by the createCollection.

Destruction disables all event listeners:
- created on the view, e.g. view.on( 'event', () => {} ),
- defined in the template for DOM events.
inherited
extendTemplate( definition )
See source
Extends the template of the view with with given definition.

A shorthand for:
```
Template.extend( view.template, definition );
```
Note: Is requires the template to be already set. See setTemplate.

Parameters

definition : TemplateDefinition

Definition which extends the template.
mixed
fire( eventOrInfo, [ args ] ) → *

See source
Fires an event, executing all callbacks registered for it.

The first parameter passed to callbacks is an EventInfo object, followed by the optional args provided in the fire() method call.

Parameters

eventOrInfo : String | EventInfo

The name of the event or EventInfo object if event is delegated.

[ args ] : *

Additional arguments to be passed to the callbacks.

Returns

*

By default the method returns undefined. However, the return value can be changed by listeners through modification of the evt.return's property (the event info is the first param of every callback).
mixed
listenTo( emitter, event, callback, [ options ] = { [options.priority] } )
See source
Registers a callback function to be executed when an event is fired in a specific (emitter) object.

Events can be grouped in namespaces using :. When namespaced event is fired, it additionally fires all callbacks for that namespace.
```
// myEmitter.on( ... ) is a shorthand for myEmitter.listenTo( myEmitter, ... ).
myEmitter.on( 'myGroup', genericCallback );
myEmitter.on( 'myGroup:myEvent', specificCallback );

// genericCallback is fired.
myEmitter.fire( 'myGroup' );
// both genericCallback and specificCallback are fired.
myEmitter.fire( 'myGroup:myEvent' );
// genericCallback is fired even though there are no callbacks for "foo".
myEmitter.fire( 'myGroup:foo' );
```
An event callback can stop the event and set the return value of the fire method.

Parameters

emitter : Emitter

The object that fires the event.

event : String

The name of the event.

callback : function

The function to be called on event.

[ options ] : Object

Additional options.

Properties

[ options.priority ] : PriorityString | Number

The priority of this event callback. The higher the priority value the sooner the callback will be fired. Events having the same priority are called in the order they were added.

Defaults to 'normal'

Defaults to {}
mixed
off( event, callback )

See source
Stops executing the callback on the given event. Shorthand for this.stopListening( this, event, callback ).

Parameters

event : String

The name of the event.

callback : function

The function to stop being called.
mixed
on( event, callback, [ options ] = { [options.priority] } )

See source
Registers a callback function to be executed when an event is fired.

Shorthand for this.listenTo( this, event, callback, options ) (it makes the emitter listen on itself).

Parameters

event : String

The name of the event.

callback : function

The function to be called on event.

[ options ] : Object

Additional options.

Properties

[ options.priority ] : PriorityString | Number

The priority of this event callback. The higher the priority value the sooner the callback will be fired. Events having the same priority are called in the order they were added.

Defaults to 'normal'

Defaults to {}
mixed
once( event, callback, [ options ] = { [options.priority] } )

See source
Registers a callback function to be executed on the next time the event is fired only. This is similar to calling on followed by off in the callback.

Parameters

event : String

The name of the event.

callback : function

The function to be called on event.

[ options ] : Object

Additional options.

Properties

[ options.priority ] : PriorityString | Number

The priority of this event callback. The higher the priority value the sooner the callback will be fired. Events having the same priority are called in the order they were added.

Defaults to 'normal'

Defaults to {}

inherited
`registerChild( children )`

See source

Registers a new child view under the view instance. Once registered, a child view is managed by its parent, including rendering and destruction.

To revert this, use deregisterChild.

class SampleView extends View {
	constructor( locale ) {
		super( locale );

		this.childA = new SomeChildView( locale );
		this.childB = new SomeChildView( locale );

		this.setTemplate( { tag: 'p' } );

		// Register the children.
		this.registerChild( [ this.childA, this.childB ] );
	}

	render() {
		super.render();

		this.element.appendChild( this.childA.element );
		this.element.appendChild( this.childB.element );
	}
}

const view = new SampleView( locale );

view.render();

// Will append <p><childA#element><b></b><childB#element></p>.
document.body.appendChild( view.element );

Note: There's no need to add child views if they're already referenced in the template:

class SampleView extends View {
	constructor( locale ) {
		super( locale );

		this.childA = new SomeChildView( locale );
		this.childB = new SomeChildView( locale );

		this.setTemplate( {
			tag: 'p',

			// These children will be added automatically. There's no
			// need to call registerChild for any of them.
			children: [ this.childA, this.childB ]
		} );
	}

	// ...
}

Parameters

children : View | Iterable.<View>: Children views to be registered.

inherited
render()
See source
Recursively renders the view.

Once the view is rendered:
- the element becomes an HTML element out of template,
- the isRendered flag is set true.
Note: The children of the view:
- defined directly in the template
- residing in collections created by the createCollection method,
- and added by registerChild are also rendered in the process.
In general, render() method is the right place to keep the code which refers to the element and should be executed at the very beginning of the view's life cycle.

It is possible to extend the template before the view is rendered. To allow an early customization of the view (e.g. by its parent), such references should be done in render().
```
class SampleView extends View {
	constructor() {
		this.setTemplate( {
			// ...
		} );
	},

	render() {
		// View#element becomes available.
		super.render();

		// The "scroll" listener depends on #element.
		this.listenTo( window, 'scroll', () => {
			// A reference to #element would render the #template and make it non-extendable.
			if ( window.scrollY > 0 ) {
				this.element.scrollLeft = 100;
			} else {
				this.element.scrollLeft = 0;
			}
		} );
	}
}

const view = new SampleView();

// Let's customize the view before it gets rendered.
view.extendTemplate( {
	attributes: {
		class: [
			'additional-class'
		]
	}
} );

// Late rendering allows customization of the view.
view.render();
```
mixed
set( name, [ value ] )

See source
Creates and sets the value of an observable property of this object. Such a property becomes a part of the state and is observable.

It accepts also a single object literal containing key/value pairs with properties to be set.

This method throws the observable-set-cannot-override error if the observable instance already has a property with the given property name. This prevents from mistakenly overriding existing properties and methods, but means that foo.set( 'bar', 1 ) may be slightly slower than foo.bar = 1.

Parameters

name : String | Object

The property's name or object with name=>value pairs.

[ value ] : *

The property's value (if name was passed in the first parameter).
inherited
setTemplate( definition )
See source
Sets the template of the view with with given definition.

A shorthand for:
```
view.setTemplate( definition );
```
Parameters

definition : TemplateDefinition

Definition of view's template.
mixed
stopDelegating( [ event ], [ emitter ] )
See source
Stops delegating events. It can be used at different levels:
- To stop delegating all events.
- To stop delegating a specific event to all emitters.
- To stop delegating a specific event to a specific emitter.
Parameters

[ event ] : String

The name of the event to stop delegating. If omitted, stops it all delegations.

[ emitter ] : Emitter

(requires event) The object to stop delegating a particular event to. If omitted, stops delegation of event to all emitters.
mixed
stopListening( [ emitter ], [ event ], [ callback ] )
See source
Stops listening for events. It can be used at different levels:
- To stop listening to a specific callback.
- To stop listening to a specific event.
- To stop listening to all events fired by a specific object.
- To stop listening to all events fired by all objects.
Parameters

[ emitter ] : Emitter

The object to stop listening to. If omitted, stops it for all objects.

[ event ] : String

(Requires the emitter) The name of the event to stop listening to. If omitted, stops it for all events from emitter.

[ callback ] : function

(Requires the event) The function to be removed from the call list for the given event.
inherited
t()
See source
Shorthand for t.

Note: If locale instance hasn't been passed to the view this method may not be available.

Related:
- Locale#t
mixed
unbind( [ unbindProperties ] )
See source
Removes the binding created with bind.
```
// Removes the binding for the 'a' property.
A.unbind( 'a' );

// Removes bindings for all properties.
A.unbind();
```
Parameters

[ unbindProperties ] : String

Observable properties to be unbound. All the bindings will be released if no properties are provided.
protected mixed
_addEventListener( event, callback, [ options ] = { [options.priority] } )

See source
Adds callback to emitter for given event.

Parameters

event : String

The name of the event.

callback : function

The function to be called on event.

[ options ] : Object

Additional options.

Properties

[ options.priority ] : PriorityString | Number

The priority of this event callback. The higher the priority value the sooner the callback will be fired. Events having the same priority are called in the order they were added.

Defaults to 'normal'

Defaults to {}
protected mixed
_removeEventListener( event, callback )

See source
Removes callback from emitter for given event.

Parameters

event : String

The name of the event.

callback : function

The function to stop being called.

Events

mixed
change:{property}( eventInfo, name, value, oldValue )
See source
Fired when a property changed value.
```
observable.set( 'prop', 1 );

observable.on( 'change:prop', ( evt, propertyName, newValue, oldValue ) => {
	console.log( `${ propertyName } has changed from ${ oldValue } to ${ newValue }` );
} );

observable.prop = 2; // -> 'prop has changed from 1 to 2'
```
Parameters

eventInfo : EventInfo

An object containing information about the fired event.

name : String

The property name.

value : *

The new property value.

oldValue : *

The previous property value.
inherited
render( eventInfo )

See source
Event fired by the render method. Actual rendering is executed as a listener to this event with the default priority.

See decorate for more information and samples.

Parameters

eventInfo : EventInfo

An object containing information about the fired event.
mixed
set:{property}( eventInfo, name, value, oldValue )
See source
Fired when a property value is going to be set but is not set yet (before the change event is fired).

You can control the final value of the property by using the event's return property.
```
observable.set( 'prop', 1 );

observable.on( 'set:prop', ( evt, propertyName, newValue, oldValue ) => {
	console.log( `Value is going to be changed from ${ oldValue } to ${ newValue }` );
	console.log( `Current property value is ${ observable[ propertyName ] }` );

	// Let's override the value.
	evt.return = 3;
} );

observable.on( 'change:prop', ( evt, propertyName, newValue, oldValue ) => {
	console.log( `Value has changed from ${ oldValue } to ${ newValue }` );
} );

observable.prop = 2; // -> 'Value is going to be changed from 1 to 2'
                     // -> 'Current property value is 1'
                     // -> 'Value has changed from 1 to 3'
```
Note: The event is fired even when the new value is the same as the old value.

Parameters

eventInfo : EventInfo

An object containing information about the fired event.

name : String

The property name.

value : *

The new property value.

oldValue : *

The previous property value.

Every day, we work hard to keep our documentation complete. Have you spotted outdated information? Is something missing? Please report it via our issue tracker.

ItemsView (ui/toolbar)

Filtering

Properties

readonly children : ViewCollectionmodule:ui/toolbar/toolbarview~ItemsView#children

inherited element : HTMLElementmodule:ui/toolbar/toolbarview~ItemsView#element

readonly inherited isRendered : Booleanmodule:ui/toolbar/toolbarview~ItemsView#isRendered

readonly inherited locale : Localemodule:ui/toolbar/toolbarview~ItemsView#locale

inherited template : Templatemodule:ui/toolbar/toolbarview~ItemsView#template

protected inherited _unboundChildren : ViewCollectionmodule:ui/toolbar/toolbarview~ItemsView#_unboundChildren

protected inherited _viewCollections : Set.<ViewCollection>module:ui/toolbar/toolbarview~ItemsView#_viewCollections

private inherited _bindTemplate : Objectmodule:ui/toolbar/toolbarview~ItemsView#_bindTemplate

Methods

inherited constructor( [ locale ] )module:ui/toolbar/toolbarview~ItemsView#constructor

Parameters

mixed bind( bindProperties ) → Objectmodule:ui/toolbar/toolbarview~ItemsView#bind

Parameters

Returns

inherited bindTemplate()module:ui/toolbar/toolbarview~ItemsView#bindTemplate

inherited createCollection( [ views ] ) → ViewCollectionmodule:ui/toolbar/toolbarview~ItemsView#createCollection

Parameters

Returns

mixed decorate( methodName )module:ui/toolbar/toolbarview~ItemsView#decorate

Parameters

mixed delegate( events ) → EmitterMixinDelegateChainmodule:ui/toolbar/toolbarview~ItemsView#delegate

Parameters

Returns

inherited deregisterChild( children )module:ui/toolbar/toolbarview~ItemsView#deregisterChild

Parameters

Related:

inherited destroy()module:ui/toolbar/toolbarview~ItemsView#destroy

inherited extendTemplate( definition )module:ui/toolbar/toolbarview~ItemsView#extendTemplate

Parameters

mixed fire( eventOrInfo, [ args ] ) → *module:ui/toolbar/toolbarview~ItemsView#fire

Parameters

Returns

mixed listenTo( emitter, event, callback, [ options ] = { [options.priority] } )module:ui/toolbar/toolbarview~ItemsView#listenTo

Parameters

mixed off( event, callback )module:ui/toolbar/toolbarview~ItemsView#off

Parameters

mixed on( event, callback, [ options ] = { [options.priority] } )module:ui/toolbar/toolbarview~ItemsView#on

Parameters

mixed once( event, callback, [ options ] = { [options.priority] } )module:ui/toolbar/toolbarview~ItemsView#once

Parameters

inherited registerChild( children )module:ui/toolbar/toolbarview~ItemsView#registerChild

Parameters

inherited render()module:ui/toolbar/toolbarview~ItemsView#render

mixed set( name, [ value ] )module:ui/toolbar/toolbarview~ItemsView#set

Parameters

inherited setTemplate( definition )module:ui/toolbar/toolbarview~ItemsView#setTemplate

Parameters

mixed stopDelegating( [ event ], [ emitter ] )module:ui/toolbar/toolbarview~ItemsView#stopDelegating

Parameters

mixed stopListening( [ emitter ], [ event ], [ callback ] )module:ui/toolbar/toolbarview~ItemsView#stopListening

Parameters

inherited t()module:ui/toolbar/toolbarview~ItemsView#t

Related:

mixed unbind( [ unbindProperties ] )module:ui/toolbar/toolbarview~ItemsView#unbind

Parameters

protected mixed _addEventListener( event, callback, [ options ] = { [options.priority] } )module:ui/toolbar/toolbarview~ItemsView#_addEventListener

Parameters

protected mixed _removeEventListener( event, callback )module:ui/toolbar/toolbarview~ItemsView#_removeEventListener

Parameters

Events

mixed change:{property}( eventInfo, name, value, oldValue )module:ui/toolbar/toolbarview~ItemsView#event:change:{property}

Parameters

inherited render( eventInfo )module:ui/toolbar/toolbarview~ItemsView#event:render

Parameters

mixed set:{property}( eventInfo, name, value, oldValue )module:ui/toolbar/toolbarview~ItemsView#event:set:{property}

Parameters

readonly
`children : ViewCollection`

inherited
`element : HTMLElement`

readonly inherited
`isRendered : Boolean`

readonly inherited
`locale : Locale`

inherited
`template : Template`

protected inherited
`_unboundChildren : ViewCollection`

protected inherited
`_viewCollections : Set.<ViewCollection>`

private inherited
`_bindTemplate : Object`

inherited
`constructor( [ locale ] )`

mixed
`bind( bindProperties ) → Object`

inherited
`bindTemplate()`

inherited
`createCollection( [ views ] ) → ViewCollection`

mixed
`decorate( methodName )`

mixed
`delegate( events ) → EmitterMixinDelegateChain`

inherited
`deregisterChild( children )`

inherited
`destroy()`

inherited
`extendTemplate( definition )`

mixed
`fire( eventOrInfo, [ args ] ) → *`

mixed
`listenTo( emitter, event, callback, [ options ] = { [options.priority] } )`

mixed
`off( event, callback )`

mixed
`on( event, callback, [ options ] = { [options.priority] } )`

mixed
`once( event, callback, [ options ] = { [options.priority] } )`

inherited
`registerChild( children )`

inherited
`render()`

mixed
`set( name, [ value ] )`

inherited
`setTemplate( definition )`

mixed
`stopDelegating( [ event ], [ emitter ] )`

mixed
`stopListening( [ emitter ], [ event ], [ callback ] )`

inherited
`t()`

mixed
`unbind( [ unbindProperties ] )`

protected mixed
`_addEventListener( event, callback, [ options ] = { [options.priority] } )`

protected mixed
`_removeEventListener( event, callback )`

mixed
`change:{property}( eventInfo, name, value, oldValue )`

inherited
`render( eventInfo )`

mixed
`set:{property}( eventInfo, name, value, oldValue )`