Home/CKEditor 5/API

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

Public
Inherited
Mixed
Protected
Private
Deprecated

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 );
```
Using a custom callback allows processing the value before passing it to the target property:
```
button.bind( 'isEnabled' ).to( command, 'value', value => value === 'heading1' );
```
It is also possible to bind to the same property in an array of observables. To bind a button to multiple commands (also Observables) so that each and every one of them must be enabled for the button to become enabled, use the following code:
```
button.bind( 'isEnabled' ).toMany( [ commandA, commandB, commandC ], 'isEnabled',
	( isAEnabled, isBEnabled, isCEnabled ) => isAEnabled && isBEnabled && isCEnabled );
```
Parameters

bindProperties : String

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

Returns

Object

The bind chain with the to() and toMany() methods.
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 a property becomes a part of the state and is 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 has a property with the given property name. This prevents from mistakenly overriding existing properties and methods, but means that foo.set( 'bar', 1 ) may be slightly slower than foo.bar = 1.

Parameters

name : String | Object

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

[ value ] : *

The property's value (if name was passed in the first parameter).
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.
_addEventListener( event, callback, [ options ] = { [options.priority] } )

protected mixed

Adds callback to emitter for given event.

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 {}
_removeEventListener( event, callback )

protected mixed

Removes callback from emitter for given event.

See source

Parameters

event : String

The name of the event.

callback : function

The function to stop being called.
_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: The event is fired even when the new value is the same as the old value.

Parameters

eventInfo : EventInfo

An object containing information about the fired event.

name : String

The property name.

value : *

The new property value.

oldValue : *

The previous property value.
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.

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TextWatcher (typing)

Filtering

Properties

hasMatch : Booleanmodule:typing/textwatcher~TextWatcher#hasMatch

isEnabled : Booleanmodule:typing/textwatcher~TextWatcher#isEnabled

model : Modelmodule:typing/textwatcher~TextWatcher#model

testCallback : functionmodule:typing/textwatcher~TextWatcher#testCallback

Methods

constructor( model, testCallback )module:typing/textwatcher~TextWatcher#constructor

Parameters

bind( bindProperties ) → Objectmodule:typing/textwatcher~TextWatcher#bind

Parameters

Returns

decorate( methodName )module:typing/textwatcher~TextWatcher#decorate

Parameters

delegate( events ) → EmitterMixinDelegateChainmodule:typing/textwatcher~TextWatcher#delegate

Parameters

Returns

fire( eventOrInfo, [ args ] ) → *module:typing/textwatcher~TextWatcher#fire

Parameters

Returns

listenTo( emitter, event, callback, [ options ] = { [options.priority] } )module:typing/textwatcher~TextWatcher#listenTo

Parameters

off( event, callback )module:typing/textwatcher~TextWatcher#off

Parameters

on( event, callback, [ options ] = { [options.priority] } )module:typing/textwatcher~TextWatcher#on

Parameters

once( event, callback, [ options ] = { [options.priority] } )module:typing/textwatcher~TextWatcher#once

Parameters

set( name, [ value ] )module:typing/textwatcher~TextWatcher#set

Parameters

stopDelegating( [ event ], [ emitter ] )module:typing/textwatcher~TextWatcher#stopDelegating

Parameters

stopListening( [ emitter ], [ event ], [ callback ] )module:typing/textwatcher~TextWatcher#stopListening

Parameters

unbind( [ unbindProperties ] )module:typing/textwatcher~TextWatcher#unbind

Parameters

_addEventListener( event, callback, [ options ] = { [options.priority] } )module:typing/textwatcher~TextWatcher#_addEventListener

Parameters

_removeEventListener( event, callback )module:typing/textwatcher~TextWatcher#_removeEventListener

Parameters

_evaluateTextBeforeSelection( suffix, data )module:typing/textwatcher~TextWatcher#_evaluateTextBeforeSelection

Parameters

Fires

_startListening()module:typing/textwatcher~TextWatcher#_startListening

Events

change:isEnabled( eventInfo, name, value, oldValue )module:typing/textwatcher~TextWatcher#event:change:isEnabled

Parameters

change:{property}( eventInfo, name, value, oldValue )module:typing/textwatcher~TextWatcher#event:change:{property}

Parameters

matched:data( eventInfo, data = { data.text, data.range, [data.testResult] } )module:typing/textwatcher~TextWatcher#event:matched:data

Parameters

matched:selection( eventInfo, data = { data.text, data.range, [data.testResult] } )module:typing/textwatcher~TextWatcher#event:matched:selection

Parameters

set:{property}( eventInfo, name, value, oldValue )module:typing/textwatcher~TextWatcher#event:set:{property}

Parameters

unmatched( eventInfo )module:typing/textwatcher~TextWatcher#event:unmatched

Parameters

`hasMatch : Boolean`

`isEnabled : Boolean`

`model : Model`

`testCallback : function`

`constructor( model, testCallback )`

`bind( bindProperties ) → Object`

`decorate( methodName )`

`delegate( events ) → EmitterMixinDelegateChain`

`fire( eventOrInfo, [ args ] ) → *`

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

`off( event, callback )`

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

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

`set( name, [ value ] )`

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

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

`unbind( [ unbindProperties ] )`

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

`_removeEventListener( event, callback )`

`_evaluateTextBeforeSelection( suffix, data )`

`_startListening()`

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

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

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

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

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

`unmatched( eventInfo )`