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Class

TextWatcher (typing)

@ckeditor/ckeditor5-typing/src/textwatcher

class private
See source

The text watcher feature.

Fires the matched:data, matched:selection and unmatched events on typing or selection changes.

Filtering

Properties

  • hasMatch : Boolean

    readonly

    Whether there is a match currently.

    See source

  • isEnabled : Boolean

    observable

    Flag indicating whether the TextWatcher instance is enabled or disabled. A disabled TextWatcher will not evaluate text.

    See source

    To disable TextWatcher:

    const watcher = new TextWatcher( editor.model, testCallback );

// After this a testCallback will not be called.
watcher.isEnabled = false;

  • model : Model

    readonly

    The editor's model.

    See source

  • testCallback : function

    The function used to match the text.

    See source

    The test callback can return 3 values:

    • false if there is no match,
    • true if there is a match,
    • an object if there is a match and we want to pass some additional information to the event-matched:data event.

Methods

  • constructor( model, testCallback )

    Creates a text watcher instance.

    See source

    Parameters

    model : Model
    testCallback : function

    See testCallback.

  • bind( bindProperties ) → Object

    mixed

    Binds observable properties to other objects implementing the Observable interface.

    See source

    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 );

    It is also possible to bind to the same property in an array of observables. To bind a button to multiple commands (also Observables) so that each and every one of them must be enabled for the button to become enabled, use the following code:

    button.bind( 'isEnabled' ).toMany( [ commandA, commandB, commandC ], 'isEnabled',
    ( isAEnabled, isBEnabled, isCEnabled ) => isAEnabled && isBEnabled && isCEnabled );

    Parameters

    bindProperties : String

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

    Returns

    Object

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

  • 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.

    See source

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

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

    For example, to cancel the method execution the event can be stopped:

    class Foo {
    constructor() {
        this.decorate( 'method' );
    }

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

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

foo.method(); // Nothing is logged.

    Note: The high priority listener has been used to execute this particular callback before the one which calls the original method (which uses the "normal" priority).

    It is also possible to change the returned value:

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

foo.method(); // -> 'Foo'

    Finally, it is possible to access and modify the arguments the method is called with:

    method( a, b ) {
    console.log( `${ a }, ${ b }`  );
}

// ...

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

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

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

    Parameters

    methodName : String

    Name of the method to decorate.

  • delegate( events ) → EmitterMixinDelegateChain

    mixed

    Delegates selected events to another Emitter. For instance:

    See source
    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

  • fire( eventOrInfo, [ args ] ) → *

    mixed

    Fires an event, executing all callbacks registered for it.

    See source

    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).

  • 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.

    See source

    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 ).

    See source

    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.

    See source

    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.

    See source

    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 {}

  • 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.

    See source

    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).

  • stopDelegating( [ event ], [ emitter ] )

    mixed

    Stops delegating events. It can be used at different levels:

    See source
    • 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:

    See source
    • 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.

  • unbind( [ unbindProperties ] )

    mixed

    Removes the binding created with bind.

    See source
    // Removes the binding for the 'a' property.
A.unbind( 'a' );

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

    Parameters

    [ unbindProperties ] : String

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

  • _evaluateTextBeforeSelection( suffix, data )

    private

    Checks the editor content for matched text.

    See source

    Parameters

    suffix : 'data' | 'selection'

    A suffix used for generating the event name.

    data : Object

    Data object for event.

    Fires

  • _startListening()

    private

    Starts listening to the editor for typing and selection events.

    See source

Events

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

    Fired when the isEnabled property changed value.

    See source

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

    mixed

    Fired when a property changed value.

    See source
    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.

  • matched:data( eventInfo, data = { data.text, data.range, [data.testResult] } )

    Fired whenever the text watcher found a match for data changes.

    See source

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    data : Object

    Event data.

    Properties
    data.text : String

    The full text before selection to which the regexp was applied.

    data.range : Range

    The range representing the position of the data.text.

    [ data.testResult ] : Object

    The additional data returned from the testCallback.

  • matched:selection( eventInfo, data = { data.text, data.range, [data.testResult] } )

    Fired whenever the text watcher found a match for selection changes.

    See source

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    data : Object

    Event data.

    Properties
    data.text : String

    The full text before selection.

    data.range : Range

    The range representing the position of the data.text.

    [ data.testResult ] : Object

    The additional data returned from the testCallback.

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

    mixed

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

    See source

    You can control the final value of the property by using the event's return property.

    observable.set( 'prop', 1 );

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

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

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

observable.prop = 2; // -> 'Value is going to be changed from 1 to 2'
                     // -> 'Current property value is 1'
                     // -> 'Value has changed from 1 to 3'

    Note: Event is fired even when the new value is the same as the old value.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

    name : String

    The property name.

    value : *

    The new property value.

    oldValue : *

    The previous property value.

  • unmatched( eventInfo )

    Fired whenever the text does not match anymore. Fired only when the text watcher found a match.

    See source

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.