Internal_List of registered DOM elements.
Internal_List of views with external focus trackers that contribute to the state of this focus tracker.
ReadonlyfocusedThe currently focused element.
While #isFocused isFocused remains true, the focus can move between different UI elements. This property tracks those
elements and tells which one is currently focused.
Note: The values of this property are restricted to #elements or module:ui/view~View#element elements registered in #externalViews.
ReadonlyisTrue when one of the registered #elements or #externalViews is focused.
List of registered DOM elements.
Note: The list does do not include elements from #externalViews.
List of external focusable views that contribute to the state of this focus tracker. See #add to learn more.
Starts tracking a specified DOM element or a module:ui/view~View instance.
focus and blur events on this element.
Tracked elements are listed in #elements.FocusTracker instance (~ViewWithFocusTracker),
the external focus tracker's state (#isFocused, #focusedElement) starts contributing to the current tracker instance.
This allows for increasing the "reach" of a focus tracker instance, by connecting two or more focus trackers together when DOM
elements they track are located in different subtrees in DOM. External focus trackers are listed in #externalViews.FocusTracker (not a ~ViewWithFocusTracker),
its module:ui/view~View#element is used to track focus like any other DOM element.Binds #set observable properties to other objects implementing the module:utils/observablemixin~Observable interface.
Read more in the {@glink framework/deep-dive/observables#property-bindings 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,command.isEnabled changes, button.isEnabled will immediately reflect its value.Note: To release the binding, use module:utils/observablemixin~Observable#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 );
Observable property that will be bound to other observable(s).
The bind chain with the to() and toMany() methods.
Binds #set observable properties to other objects implementing the module:utils/observablemixin~Observable interface.
Read more in the {@glink framework/deep-dive/observables#property-bindings 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,command.isEnabled changes, button.isEnabled will immediately reflect its value.Note: To release the binding, use module:utils/observablemixin~Observable#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 );
The bind chain with the to() and toMany() methods.
Binds #set observable properties to other objects implementing the module:utils/observablemixin~Observable interface.
Read more in the {@glink framework/deep-dive/observables#property-bindings 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,command.isEnabled changes, button.isEnabled will immediately reflect its value.Note: To release the binding, use module:utils/observablemixin~Observable#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 );
Observable properties that will be bound to other observable(s).
The bind chain with the to() and toMany() methods.
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 {@glink framework/deep-dive/observables#decorating-object-methods 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 module:utils/eventinfo~EventInfo#stop 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 module:utils/priorities~PriorityString 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'
Name of the method to decorate.
Delegates selected events to another module:utils/emittermixin~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 );
Event names that will be delegated to another emitter.
Destroys the focus tracker by:
Fires an event, executing all callbacks registered for it.
The first parameter passed to callbacks is an module:utils/eventinfo~EventInfo object,
followed by the optional args provided in the fire() method call.
The type describing the event. See module:utils/emittermixin~BaseEvent.
The name of the event or EventInfo object if event is delegated.
Additional arguments to be passed to the callbacks.
By default the method returns undefined. However, the return value can be changed by listeners
through modification of the module:utils/eventinfo~EventInfo#return evt.return's property (the event info
is the first param of every callback).
Registers a callback function to be executed when an event is fired in a specific Emitter or DOM Node. It is backwards compatible with module:utils/emittermixin~Emitter#listenTo.
The object that fires the event.
The name of the event.
The function to be called on event.
Optionaloptions: CallbackOptions & { useCapture?: boolean; usePassive?: boolean }Additional options.
Optional ReadonlyuseCapture?: booleanIndicates that events of this type will be dispatched to the registered listener before being dispatched to any EventTarget beneath it in the DOM tree.
Optional ReadonlyusePassive?: booleanIndicates that the function specified by listener will never call preventDefault() and prevents blocking browser's main thread by this event handler.
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 module:utils/eventinfo~EventInfo#stop stop the event and set the module:utils/eventinfo~EventInfo#return return value of the #fire method.
The type describing the event. See module:utils/emittermixin~BaseEvent.
The object that fires the event.
The name of the event.
The function to be called on event.
Optionaloptions: CallbackOptionsAdditional options.
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 module:utils/eventinfo~EventInfo#stop stop the event and set the module:utils/eventinfo~EventInfo#return return value of the #fire method.
The type describing the event. See module:utils/emittermixin~BaseEvent.
The object that fires the event.
The name of the event.
The function to be called on event.
Optionaloptions: GetCallbackOptions<TEvent>Additional options.
Stops executing the callback on the given event.
Shorthand for #stopListening this.stopListening( this, event, callback ).
The name of the event.
The function to stop being called.
Registers a callback function to be executed when an event is fired.
Shorthand for #listenTo this.listenTo( this, event, callback, options ) (it makes the emitter
listen on itself).
The type descibing the event. See module:utils/emittermixin~BaseEvent.
The name of the event.
The function to be called on event.
Optionaloptions: GetCallbackOptions<TEvent>Additional options.
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.
The type descibing the event. See module:utils/emittermixin~BaseEvent.
The name of the event.
The function to be called on event.
Optionaloptions: GetCallbackOptions<TEvent>Additional options.
Stops tracking focus in the specified DOM element or a module:ui/view~View view instance. See #add to learn more.
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 );
}
The property's name.
The property's value.
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'
} );
}
An object with name=>value pairs.
Optional Readonly Internal_elements?: unknownList of registered DOM elements.
Optional Readonly Internal_externalViews?: unknownList of views with external focus trackers that contribute to the state of this focus tracker.
Optionaladd?: unknownOptionalbind?: unknownOptionaldecorate?: unknownOptionaldelegate?: unknownOptionaldestroy?: unknownOptionalelements?: unknownOptionalexternalViews?: unknownOptionalfire?: unknownOptional ReadonlyfocusedElement?: unknownThe currently focused element.
While #isFocused isFocused remains true, the focus can move between different UI elements. This property tracks those
elements and tells which one is currently focused.
Note: The values of this property are restricted to #elements or module:ui/view~View#element elements registered in #externalViews.
Optional ReadonlyisFocused?: unknownTrue when one of the registered #elements or #externalViews is focused.
OptionallistenTo?: unknownOptionaloff?: unknownOptionalon?: unknownOptionalonce?: unknownOptionalremove?: unknownOptionalset?: unknownOptionalstopDelegating?: unknownOptionalstopListening?: unknownOptionalunbind?: unknownStops delegating events. It can be used at different levels:
Optionalevent: stringThe name of the event to stop delegating. If omitted, stops it all delegations.
Optionalemitter: Emitter(requires event) The object to stop delegating a particular event to.
If omitted, stops delegation of event to all emitters.
Stops listening for events. It can be used at different levels: It is backwards compatible with module:utils/emittermixin~Emitter#listenTo.
Optionalemitter: Node | EventTarget | Emitter | WindowThe object to stop listening to. If omitted, stops it for all objects.
Optionalevent: string(Requires the emitter) The name of the event to stop listening to. If omitted, stops it
for all events from emitter.
Optionalcallback: Function(Requires the event) The function to be removed from the call list for the given
event.
Stops listening for events. It can be used at different levels:
Optionalemitter: EmitterThe object to stop listening to. If omitted, stops it for all objects.
Optionalevent: string(Requires the emitter) The name of the event to stop listening to. If omitted, stops it
for all events from emitter.
Optionalcallback: Function(Requires the event) The function to be removed from the call list for the given
event.
Removes the binding created with #bind.
// Removes the binding for the 'a' property.
A.unbind( 'a' );
// Removes bindings for all properties.
A.unbind();
Observable properties to be unbound. All the bindings will be released if no properties are provided.
Allows observing a group of DOM
Elements or module:ui/view~View view instances whether at least one of them (or their child) is focused.Used by the module:core/editor/editor~Editor in order to track whether the focus is still within the application, or were used outside of its UI.
Note
focusandblurlisteners use event capturing, so it is only needed to register wrapperElementwhich contain otherfocusableelements. But note that this wrapper element has to be focusable too (have e.g.tabindex="-1").Check out the {@glink framework/deep-dive/ui/focus-tracking "Deep dive into focus tracking"} guide to learn more.