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Class

DropdownButtonView (ui/dropdown/button)

@ckeditor/ckeditor5-ui/src/dropdown/button/dropdownbuttonview

class

The default dropdown button view class.

const view = new DropdownButtonView();

view.set( {
    label: 'A button',
    keystroke: 'Ctrl+B',
    tooltip: true
} );

view.render();

document.body.append( view.element );

Also see the createDropdown() util.

Filtering

Properties

  • arrowView : IconView

    readonly

    An icon that displays arrow to indicate a dropdown button.

  • children : ViewCollection

    readonly inherited

    Collection of the child views inside of the button element.

  • element : HTMLElement

    inherited

    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' );
  • icon : String

    inherited observable

    (Optional) An XML content of the icon. When defined, an iconView should be added to the button.

  • iconView : IconView

    readonly inherited

    The icon view of the button. Will be added to children when the icon attribute is defined.

  • isEnabled : Boolean

    inherited observable

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

    To change the "on" state of the button, use isOn instead.

    Defaults to true

  • isOn : Boolean

    inherited observable

    Controls whether the button view is "on". It makes sense when a feature it represents is currently active, e.g. a bold button is "on" when the selection is in the bold text.

    To disable the button, use isEnabled instead.

    Defaults to true

  • isRendered : Boolean

    readonly inherited

    Set true when the view has already been rendered.

  • isVisible : Boolean

    inherited observable

    Controls whether the button view is visible. Visible by default, buttons are hidden using a CSS class.

    Defaults to true

  • keystroke : Boolean

    inherited observable

    (Optional) The keystroke associated with the button, i.e. CTRL+B, in the string format compatible with keyboard.

  • label : String

    inherited observable

    The label of the button view visible to the user when withText is true. It can also be used to create a tooltip.

  • labelView : View

    readonly inherited

    Label of the button view. It is configurable using the label attribute.

  • locale : Locale

    readonly inherited

    A set of tools to localize the user interface.

    Also see locale.

  • tabindex : String

    inherited observable

    (Optional) Controls the tabindex HTML attribute of the button. By default, the button is focusable but does not included in the Tab order.

    Defaults to -1

  • template : Template

    inherited

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

  • tooltip : Boolean | String | function

    inherited observable

    (Optional) Tooltip of the button, i.e. displayed when hovering the button with the mouse cursor.

    • If defined as a Boolean (e.g. true), then combination of label and keystroke will be set as a tooltip.
    • If defined as a String, tooltip will equal the exact text of that String.
    • If defined as a Function, label and keystroke will be passed to that function, which is to return a string with the tooltip text.

        const view = new ButtonView( locale );
        view.tooltip = ( label, keystroke ) => `A tooltip for ${ label } and ${ keystroke }.`

    Defaults to false

  • tooltipPosition : 's' | 'n'

    inherited observable

    (Optional) The position of the tooltip. See position to learn more about the available position values.

    Note: It makes sense only when the tooltip attribute is defined.

    Defaults to 's'

  • tooltipView : TooltipView

    readonly inherited

    Tooltip of the button view. It is configurable using the tooltip attribute.

  • type : 'button' | 'submit' | 'reset' | 'menu'

    inherited observable

    The HTML type of the button. Default button.

  • withText : Boolean

    inherited observable

    (Optional) Controls whether the label of the button is hidden (e.g. an icon–only button).

    Defaults to false

  • _unboundChildren : ViewCollection

    protected inherited

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

  • _viewCollections : Set.<ViewCollection>

    protected inherited

    Collections registered with createCollection.

  • _bindTemplate : Object

    private inherited

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

  • _tooltipString : Boolean

    private inherited observable

    Tooltip of the button bound to the template.

Methods

  • constructor( [ locale ] )

    inherited

    Creates an instance of the View class.

    Also see render.

    Parameters

    [ locale ] : Locale

    The localization services instance.

  • bind( bindProperties ) → Object

    mixed

    Binds observable properties to another objects implementing Observable interface (like Model).

    Once bound, the observable will immediately share the current state of properties of the observable it is bound to and react to the changes to these properties in the future.

    Note: To release the binding use unbind.

    Using bind().to() chain:

    A.bind( 'a' ).to( B );
    A.bind( 'a' ).to( B, 'b' );
    A.bind( 'a', 'b' ).to( B, 'c', 'd' );
    A.bind( 'a' ).to( B, 'b', C, 'd', ( b, d ) => b + d );

    It is also possible to bind to the same property in a observables collection using bind().toMany() chain:

    A.bind( 'a' ).toMany( [ B, C, D ], 'x', ( a, b, c ) => a + b + c );
    A.bind( 'a' ).toMany( [ B, C, D ], 'x', ( ...x ) => x.every( x => x ) );

    Parameters

    bindProperties : String

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

    Returns

    Object

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

  • bindTemplate()

    inherited

    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' )
                }
            } );
        }
    }
  • Creates a new collection of views, which can be used as children of this view.

    class SampleView extends View {
        constructor( locale ) {
            super( locale );
    
            this.items = this.createCollection();
    
            this.setTemplate( {
                tag: 'p',
    
                // `items` collection will render here.
                children: this.items
            } );
        }
    }
    
    const view = new SampleView( locale );
    const child = new ChildView( locale );
    
    view.render();
    
    // It will append <p></p> to the <body>.
    document.body.appendChild( view.element );
    
    // From now on the child is nested under its parent, which is also reflected in DOM.
    // <p><child#element></p>
    view.items.add( child );

    Returns

    ViewCollection

    A new collection of view instances.

  • decorate( methodName )

    mixed

    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.

    This is a very simplified method decoration. Itself it doesn't change the behavior of a method (expect adding the event), but it allows to modify it later on by listening to the method's event.

    For example, in order to cancel the method execution one can stop the event:

    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: we used a high priority listener here to execute this callback before the one which calls the original method (which used the default priority).

    It's also possible to change the return value:

    foo.on( 'method', ( evt ) => {
        evt.return = 'Foo!';
    } );
    
    foo.method(); // -> 'Foo'

    Finally, it's possible to access and modify the parameters:

    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.

  • delegate( events ) → EmitterMixinDelegateChain

    mixed

    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
  • deregisterChild( children )

    inherited

    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.

  • destroy()

    inherited

    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.
  • extendTemplate( definition )

    inherited

    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.

  • fire( eventOrInfo, [ args ] ) → *

    mixed

    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).

  • focus()

    inherited

    Focuses the element of the button.

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

    mixed

    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 {}

  • off( event, callback )

    mixed

    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.

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

    mixed

    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 {}

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

    mixed

    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 {}

  • registerChild( children )

    inherited

    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.

  • render()

    inherited

    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();
    Overrides: ButtonView#render
  • set( name, [ value ] )

    mixed

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

  • setTemplate( definition )

    inherited

    Sets the template of the view with with given definition.

    A shorthand for:

    view.setTemplate( definition );

    Parameters

    definition : TemplateDefinition

    Definition of view's template.

  • stopDelegating( [ event ], [ emitter ] )

    mixed

    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.

  • stopListening( [ emitter ], [ event ], [ callback ] )

    mixed

    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.

  • t()

    inherited

    Shorthand for t.

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

  • unbind( [ unbindProperties ] )

    mixed

    Removes the binding created with bind.

    A.unbind( 'a' );
    A.unbind();

    Parameters

    [ unbindProperties ] : String

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

  • _createArrowView() → IconView

    private

    Creates a IconView instance as arrowView.

    Returns

    IconView
  • _createLabelView() → View

    private inherited

    Creates a label view instance and binds it with button attributes.

    Returns

    View
  • _createTooltipView() → TooltipView

    private inherited

    Creates a TooltipView instance and binds it with button attributes.

    Returns

    TooltipView
  • _getTooltipString( tooltip, label, keystroke ) → String

    private inherited

    Gets the text for the tooltipView from the combination of tooltip, label and keystroke attributes.

    Parameters

    tooltip : Boolean | String | function

    Button tooltip.

    label : String

    Button label.

    keystroke : String

    Button keystroke.

    Returns

    String

Events

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

    private inherited

    Fired when the _tooltipString property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (_tooltipString).

    value : Boolean

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

    oldValue : Boolean

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

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

    inherited

    Fired when the icon property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (icon).

    value : String

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

    oldValue : String

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

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

    inherited

    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:isOn( eventInfo, name, value, oldValue )

    inherited

    Fired when the isOn property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (isOn).

    value : Boolean

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

    oldValue : Boolean

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

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

    inherited

    Fired when the isVisible property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (isVisible).

    value : Boolean

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

    oldValue : Boolean

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

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

    inherited

    Fired when the keystroke property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (keystroke).

    value : Boolean

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

    oldValue : Boolean

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

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

    inherited

    Fired when the label property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (label).

    value : String

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

    oldValue : String

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

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

    inherited

    Fired when the tabindex property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (tabindex).

    value : String

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

    oldValue : String

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

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

    inherited

    Fired when the tooltip property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (tooltip).

    value : Boolean | String | function

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

    oldValue : Boolean | String | function

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

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

    inherited

    Fired when the tooltipPosition property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (tooltipPosition).

    value : 's' | 'n'

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

    oldValue : 's' | 'n'

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

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

    inherited

    Fired when the type property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (type).

    value : 'button' | 'submit' | 'reset' | 'menu'

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

    oldValue : 'button' | 'submit' | 'reset' | 'menu'

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

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

    inherited

    Fired when the withText property changed value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    Name of the changed property (withText).

    value : Boolean

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

    oldValue : Boolean

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

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

    mixed

    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.

  • execute( eventInfo )

    inherited

    Fired when the button view is clicked. It won't be fired when the button isEnabled is false.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

  • open( eventInfo )

    Fired when the dropdown should be opened. It will not be fired when the button is disabled.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

  • render( eventInfo )

    inherited

    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.