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Class

DropdownView (ui/dropdown)

@ckeditor/ckeditor5-ui/src/dropdown/dropdownview

class
See source

The dropdown view class. It manages the dropdown button and dropdown panel.

In most cases, the easiest way to create a dropdown is by using the createDropdown util:

const dropdown = createDropdown( locale );

// Configure dropdown's button properties:
dropdown.buttonView.set( {
	label: 'A dropdown',
	withText: true
} );

dropdown.render();

dropdown.panelView.element.textContent = 'Content of the panel';

// Will render a dropdown with a panel containing a "Content of the panel" text.
document.body.appendChild( dropdown.element );

If you want to add a richer content to the dropdown panel, you can use the addListToDropdown and addToolbarToDropdown helpers. See more examples in createDropdown documentation.

If you want to create a completely custom dropdown, then you can compose it manually:

const button = new DropdownButtonView( locale );
const panel = new DropdownPanelView( locale );
const dropdown = new DropdownView( locale, button, panel );

button.set( {
	label: 'A dropdown',
	withText: true
} );

dropdown.render();

panel.element.textContent = 'Content of the panel';

// Will render a dropdown with a panel containing a "Content of the panel" text.
document.body.appendChild( dropdown.element );

However, dropdown created this way will contain little behavior. You will need to implement handlers for actions such as clicking outside an open dropdown (which should close it) and support for arrow keys inside the panel. Therefore, unless you really know what you do and you really need to do it, it is recommended to use the createDropdown helper.

Filtering

Properties

  • readonly

    _panelPositions : Array<PositioningFunction>

    See source

    Returns panel positions to be used by the getOptimalPosition() utility considering the direction of the language the UI of the editor is displayed in.

  • observable

    ariaDescribedById : undefined | string

    See source

  • readonly inherited

    bindTemplate : BindChain<this>

    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' )
			}
		} );
	}
}

  • readonly

    buttonView : object

    See source

    Button of the dropdown view. Clicking the button opens the panelView.

  • observable

    class : undefined | string

    See source

    (Optional) The additional CSS class set on the dropdown element.

  • inherited

    element : null | HTMLDivElement

    See source

    An HTML element of the view. null until rendered from the template.

    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

    focusTracker : FocusTracker

    See source

    Tracks information about the DOM focus in the dropdown.

  • observable

    id : undefined | string

    See source

    (Optional) The id attribute of the dropdown (i.e. to pair with a <label> element).

  • observable

    isEnabled : boolean

    See source

    Controls whether the dropdown is enabled, i.e. it can be clicked and execute an action.

    See isEnabled.

  • observable

    isOpen : boolean

    See source

    Controls whether the dropdown view is open, i.e. shows or hides the panel.

    Note: When the dropdown gets open, it will attempt to call focus() on the first child of its panelView. See addToolbarToDropdown, addListToDropdown, and focusChildOnDropdownOpen to learn more about focus management in dropdowns.

  • inherited

    isRendered : boolean

    See source

    Set true when the view has already been rendered.

  • readonly

    keystrokes : KeystrokeHandler

    See source

    Instance of the KeystrokeHandler. It manages keystrokes of the dropdown:

    • ▼ opens the dropdown,
    • ◀ and Esc closes the dropdown.

  • listView : ListView | undefined

    See source

    A child list view of the dropdown located in its panel.

    Note: Only supported when dropdown has list view added using addListToDropdown.

  • inherited

    locale : undefined | Locale

    See source

    A set of tools to localize the user interface.

    Also see locale.

  • menuView : DropdownMenuRootListView | undefined

    See source

    A child menu component of the dropdown located in its panel.

    Note: Only supported when dropdown has a menu added using addMenuToDropdown.

  • observable

    panelPosition : 'auto' | PanelPosition

    See source

    The position of the panel, relative to the dropdown.

    Note: When 'auto', the panel will use one of the remaining positions to stay in the viewport, visible to the user. The positions correspond directly to default panel positions.

    Note: This value has an impact on the position property each time the panel becomes open.

    Defaults to 'auto'

  • readonly

    panelView : DropdownPanelView

    See source

    Panel of the dropdown. It opens when the buttonView is executed (i.e. clicked).

    Child views can be added to the panel's children collection:

    dropdown.panelView.children.add( childView );

    See children and add.

  • inherited

    t : undefined | LocaleTranslate

    See source

    Shorthand for t.

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

    Related:

  • inherited

    template : Template | undefined

    See source

    Template of this view. It provides the element representing the view in DOM, which is rendered.

  • toolbarView : ToolbarView | undefined

    See source

    A child toolbar of the dropdown located in the panel.

    Note: Only supported when dropdown has a toolbar added using addToolbarToDropdown.

  • inherited

    viewUid : string | undefined

    See source

  • protected inherited

    _unboundChildren : ViewCollection<View<HTMLElement>>

    See source

    A collection of view instances, which have been added directly into the children.

  • protected inherited

    _viewCollections : Collection<ViewCollection<View<HTMLElement>>>

    See source

    Collections registered with createCollection.

Static properties

  • static

    defaultPanelPositions : Record<string, PositioningFunction>

    See source

    A set of positioning functions used by the dropdown view to determine the optimal position (i.e. fitting into the browser viewport) of its panel when panelPosition is set to 'auto'`.

    The available positioning functions are as follow:

    South

    • south
    			[ Button ]
		+-----------------+
		|      Panel      |
		+-----------------+
    • southEast
    		[ Button ]
		+-----------------+
		|      Panel      |
		+-----------------+
    • southWest
    		         [ Button ]
		+-----------------+
		|      Panel      |
		+-----------------+
    • southMiddleEast
    		  [ Button ]
		+-----------------+
		|      Panel      |
		+-----------------+
    • southMiddleWest
    		       [ Button ]
		+-----------------+
		|      Panel      |
		+-----------------+

    North

    • north
    		+-----------------+
		|      Panel      |
		+-----------------+
		    [ Button ]
    • northEast
    		+-----------------+
		|      Panel      |
		+-----------------+
		[ Button ]
    • northWest
    		+-----------------+
		|      Panel      |
		+-----------------+
		         [ Button ]
    • northMiddleEast
    		+-----------------+
		|      Panel      |
		+-----------------+
		  [ Button ]
    • northMiddleWest
    		+-----------------+
		|      Panel      |
		+-----------------+
		       [ Button ]

    Positioning functions are compatible with DomPoint.

    The name that position function returns will be reflected in dropdown panel's class that controls its placement. See panelPosition to learn more.

  • private static

    _getOptimalPosition : ( Options ) => ( DomPoint | null )

    See source

    A function used to calculate the optimal position for the dropdown panel.

Methods

  • constructor( locale, buttonView, panelView )

    See source

    Creates an instance of the dropdown.

    Also see render.

    Parameters

    locale : undefined | Locale

    The localization services instance.

    buttonView : object
    panelView : DropdownPanelView

  • inherited

    bind( bindProperties ) → MultiBindChain

    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 : Array<'off' | 'on' | 'once' | 'listenTo' | 'stopListening' | 'fire' | 'delegate' | 'stopDelegating' | 'set' | 'bind' | 'unbind' | 'decorate' | 'element' | 'template' | 'focus' | 'id' | 'isRendered' | 'locale' | 't' | 'viewUid' | 'bindTemplate' | 'createCollection' | 'registerChild' | 'deregisterChild' | 'setTemplate' | 'extendTemplate' | 'render' | 'destroy' | 'class' | 'focusTracker' | 'isEnabled' | 'isOpen' | 'buttonView' | 'panelView' | 'keystrokes' | 'panelPosition' | 'listView' | 'toolbarView' | 'menuView' | 'ariaDescribedById'>

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

    Returns

    MultiBindChain

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

  • inherited

    bind( bindProperty1, bindProperty2 ) → DualBindChain<K1, DropdownView[ K1 ], K2, DropdownView[ K2 ]>

    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 );

    Type parameters

    K1
    K2

    Parameters

    bindProperty1 : K1

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

    bindProperty2 : K2

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

    Returns

    DualBindChain<K1, DropdownView[ K1 ], K2, DropdownView[ K2 ]>

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

  • inherited

    bind( bindProperty ) → SingleBindChain<K, DropdownView[ K ]>

    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 );

    Type parameters

    K

    Parameters

    bindProperty : K

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

    Returns

    SingleBindChain<K, DropdownView[ K ]>

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

  • inherited

    createCollection( [ views ] ) → ViewCollection<T>

    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 );

    Type parameters

    T : extends [object Object] = default

    Parameters

    [ views ] : Iterable<T>

    Initial views of the collection.

    Returns

    ViewCollection<T>

    A new collection of view instances.

  • inherited

    decorate( methodName ) → void

    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 extends ObservableMixin() {
	constructor() {
		super();
		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 : 'off' | 'on' | 'once' | 'listenTo' | 'stopListening' | 'fire' | 'delegate' | 'stopDelegating' | 'set' | 'bind' | 'unbind' | 'decorate' | 'element' | 'template' | 'focus' | 'id' | 'isRendered' | 'locale' | 't' | 'viewUid' | 'bindTemplate' | 'createCollection' | 'registerChild' | 'deregisterChild' | 'setTemplate' | 'extendTemplate' | 'render' | 'destroy' | 'class' | 'focusTracker' | 'isEnabled' | 'isOpen' | 'buttonView' | 'panelView' | 'keystrokes' | 'panelPosition' | 'listView' | 'toolbarView' | 'menuView' | 'ariaDescribedById'

    Name of the method to decorate.

    Returns

    void

  • inherited

    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 : Array<string>

    Event names that will be delegated to another emitter.

    Returns

    EmitterMixinDelegateChain

  • inherited

    deregisterChild( children ) → void

    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<HTMLElement> | Iterable<View<HTMLElement>>

    Child views to be removed.

    Returns

    void

    Related:

  • inherited

    destroy() → void

    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.

    Returns

    void

  • inherited

    extendTemplate( definition ) → void

    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 : Partial<TemplateDefinition>

    Definition which extends the template.

    Returns

    void

  • inherited

    fire( eventOrInfo, args ) → GetEventInfo<TEvent>[ 'return' ]

    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.

    Type parameters

    TEvent : extends BaseEvent

    The type describing the event. See BaseEvent.

    Parameters

    eventOrInfo : GetNameOrEventInfo<TEvent>

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

    args : TEvent[ 'args' ]

    Additional arguments to be passed to the callbacks.

    Returns

    GetEventInfo<TEvent>[ 'return' ]

    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).

  • focus() → void

    See source

    Focuses the buttonView.

    Returns

    void

  • inherited

    listenTo( emitter, event, callback, [ options ] ) → void

    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.

    Type parameters

    TEvent : extends BaseEvent

    The type describing the event. See BaseEvent.

    Parameters

    emitter : Emitter

    The object that fires the event.

    event : TEvent[ 'name' ]

    The name of the event.

    callback : GetCallback<TEvent>

    The function to be called on event.

    [ options ] : CallbackOptions

    Additional options.

    Returns

    void

  • inherited

    listenTo( emitter, event, callback, [ options ] ) → void

    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.

    Type parameters

    TEvent : extends BaseEvent

    The type describing the event. See BaseEvent.

    Parameters

    emitter : Emitter

    The object that fires the event.

    event : TEvent[ 'name' ]

    The name of the event.

    callback : GetCallback<TEvent>

    The function to be called on event.

    [ options ] : GetCallbackOptions<TEvent>

    Additional options.

    Returns

    void

  • inherited

    listenTo( emitter, event, callback, [ options ] ) → void

    See source

    Registers a callback function to be executed when an event is fired in a specific Emitter or DOM Node. It is backwards compatible with listenTo.

    Type parameters

    K : extends keyof DomEventMap

    Parameters

    emitter : Window | Node

    The object that fires the event.

    event : K

    The name of the event.

    callback : ( DropdownView, EventInfo<string, unknown>, DomEventMap[ K ] ) => void

    The function to be called on event.

    [ options ] : object

    Additional options.

    Returns

    void

  • inherited

    off( event, callback ) → void

    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.

    Returns

    void

  • inherited

    on( event, callback, [ options ] ) → void

    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).

    Type parameters

    TEvent : extends BaseEvent

    The type descibing the event. See BaseEvent.

    Parameters

    event : TEvent[ 'name' ]

    The name of the event.

    callback : GetCallback<TEvent>

    The function to be called on event.

    [ options ] : GetCallbackOptions<TEvent>

    Additional options.

    Returns

    void

  • inherited

    once( event, callback, [ options ] ) → void

    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.

    Type parameters

    TEvent : extends BaseEvent

    The type descibing the event. See BaseEvent.

    Parameters

    event : TEvent[ 'name' ]

    The name of the event.

    callback : GetCallback<TEvent>

    The function to be called on event.

    [ options ] : GetCallbackOptions<TEvent>

    Additional options.

    Returns

    void

  • inherited

    registerChild( children ) → void

    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<HTMLElement> | Iterable<View<HTMLElement>>

    Children views to be registered.

    Returns

    void

  • render() → void

    See source

    Recursively renders the view.

    Once the view is rendered:

    Note: The children of the view:

    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();

    Returns

    void

  • inherited

    set( values ) → void

    See source

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

    It accepts 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.

    In TypeScript, those properties should be declared in class using declare keyword. In example:

    public declare myProp1: number;
public declare myProp2: string;

constructor() {
	this.set( {
		'myProp1: 2,
		'myProp2: 'foo'
	} );
}

    Parameters

    values : object

    An object with name=>value pairs.

    Returns

    void

  • inherited

    set( name, value ) → void

    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.

    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.

    In TypeScript, those properties should be declared in class using declare keyword. In example:

    public declare myProp: number;

constructor() {
	this.set( 'myProp', 2 );
}

    Type parameters

    K

    Parameters

    name : K

    The property's name.

    value : DropdownView[ K ]

    The property's value.

    Returns

    void

  • inherited

    setTemplate( definition ) → void

    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.

    Returns

    void

  • inherited

    stopDelegating( [ event ], [ emitter ] ) → void

    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.

    Returns

    void

  • inherited

    stopListening( [ emitter ], [ event ], [ callback ] ) → void

    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.

    Returns

    void

  • inherited

    stopListening( [ emitter ], [ event ], [ callback ] ) → void

    See source

    Stops listening for events. It can be used at different levels: It is backwards compatible with listenTo.

    • 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 ] : Window | Node | 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.

    Returns

    void

  • inherited

    unbind( unbindProperties ) → void

    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 : Array<'off' | 'on' | 'once' | 'listenTo' | 'stopListening' | 'fire' | 'delegate' | 'stopDelegating' | 'set' | 'bind' | 'unbind' | 'decorate' | 'element' | 'template' | 'focus' | 'id' | 'isRendered' | 'locale' | 't' | 'viewUid' | 'bindTemplate' | 'createCollection' | 'registerChild' | 'deregisterChild' | 'setTemplate' | 'extendTemplate' | 'render' | 'destroy' | 'class' | 'focusTracker' | 'isEnabled' | 'isOpen' | 'buttonView' | 'panelView' | 'keystrokes' | 'panelPosition' | 'listView' | 'toolbarView' | 'menuView' | 'ariaDescribedById'>

    Observable properties to be unbound. All the bindings will be released if no properties are provided.

    Returns

    void

Events

  • change:ariaDescribedById( eventInfo, name, value, oldValue )

    See source

    Fired when the ariaDescribedById property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (ariaDescribedById).

    value : undefined | string

    New value of the ariaDescribedById property with given key or null, if operation should remove property.

    oldValue : undefined | string

    Old value of the ariaDescribedById property with given key or null, if property was not set before.

  • change:class( eventInfo, name, value, oldValue )

    See source

    Fired when the class property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (class).

    value : undefined | string

    New value of the class property with given key or null, if operation should remove property.

    oldValue : undefined | string

    Old value of the class property with given key or null, if property was not set before.

  • change:id( eventInfo, name, value, oldValue )

    See source

    Fired when the id property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (id).

    value : undefined | string

    New value of the id property with given key or null, if operation should remove property.

    oldValue : undefined | string

    Old value of the id property with given key or null, if property was not set before.

  • change:isEnabled( eventInfo, name, value, oldValue )

    See source

    Fired when the isEnabled property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (isEnabled).

    value : boolean

    New value of the isEnabled property with given key or null, if operation should remove property.

    oldValue : boolean

    Old value of the isEnabled property with given key or null, if property was not set before.

  • change:isOpen( eventInfo, name, value, oldValue )

    See source

    Fired when the isOpen property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (isOpen).

    value : boolean

    New value of the isOpen property with given key or null, if operation should remove property.

    oldValue : boolean

    Old value of the isOpen property with given key or null, if property was not set before.

  • change:panelPosition( eventInfo, name, value, oldValue )

    See source

    Fired when the panelPosition property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (panelPosition).

    value : 'auto' | PanelPosition

    New value of the panelPosition property with given key or null, if operation should remove property.

    oldValue : 'auto' | PanelPosition

    Old value of the panelPosition property with given key or null, if property was not set before.

  • inherited

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

    See source

    Fired when a property changed value.

    observable.set( 'prop', 1 );

observable.on<ObservableChangeEvent<number>>( '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 : TValue

    The new property value.

    oldValue : TValue

    The previous property value.

  • execute( eventInfo )

    See source

    Fired when an item inside the dropdown is executed.

    Note: Only supported when dropdown was integrated with its child view using one of the helper functions: addListToDropdown, addToolbarToDropdown, or addMenuToDropdown.

    When integrated with a list, it fires when a child of one of ListItemViews fired execute event.

    When integrated with a toolbar, it fires when one of the buttons has been executed.

    When integrated with a nested menu, it fires when one of the menu buttons has been executed.

    In each case, the event is delegated from the component which fired it. It does not have additional parameters and event.source is the original component.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

  • inherited

    render( eventInfo, <anonymous> )

    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.

    <anonymous> : Parameters<TObservable[ TName ]>

  • set:ariaDescribedById( eventInfo, name, value, oldValue )

    See source

    Fired when the ariaDescribedById property is going to be set but is not set yet (before the change event is fired).

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (ariaDescribedById).

    value : undefined | string

    New value of the ariaDescribedById property with given key or null, if operation should remove property.

    oldValue : undefined | string

    Old value of the ariaDescribedById property with given key or null, if property was not set before.

  • set:class( eventInfo, name, value, oldValue )

    See source

    Fired when the class property is going to be set but is not set yet (before the change event is fired).

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (class).

    value : undefined | string

    New value of the class property with given key or null, if operation should remove property.

    oldValue : undefined | string

    Old value of the class property with given key or null, if property was not set before.

  • set:id( eventInfo, name, value, oldValue )

    See source

    Fired when the id property is going to be set but is not set yet (before the change event is fired).

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (id).

    value : undefined | string

    New value of the id property with given key or null, if operation should remove property.

    oldValue : undefined | string

    Old value of the id property with given key or null, if property was not set before.

  • set:isEnabled( eventInfo, name, value, oldValue )

    See source

    Fired when the isEnabled property is going to be set but is not set yet (before the change event is fired).

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (isEnabled).

    value : boolean

    New value of the isEnabled property with given key or null, if operation should remove property.

    oldValue : boolean

    Old value of the isEnabled property with given key or null, if property was not set before.

  • set:isOpen( eventInfo, name, value, oldValue )

    See source

    Fired when the isOpen property is going to be set but is not set yet (before the change event is fired).

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (isOpen).

    value : boolean

    New value of the isOpen property with given key or null, if operation should remove property.

    oldValue : boolean

    Old value of the isOpen property with given key or null, if property was not set before.

  • set:panelPosition( eventInfo, name, value, oldValue )

    See source

    Fired when the panelPosition property is going to be set but is not set yet (before the change event is fired).

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : string

    Name of the changed property (panelPosition).

    value : 'auto' | PanelPosition

    New value of the panelPosition property with given key or null, if operation should remove property.

    oldValue : 'auto' | PanelPosition

    Old value of the panelPosition property with given key or null, if property was not set before.

  • inherited

    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<ObservableSetEvent<number>>( '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<ObservableChangeEvent<number>>( '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 : TValue

    The new property value.

    oldValue : TValue

    The previous property value.

  • inherited

    submit( eventInfo )

    See source

    Fired by submitHandler helper.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.