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Class

DataController (engine/controller)

@ckeditor/ckeditor5-engine/src/controller/datacontroller

class

Controller for the data pipeline. The data pipeline controls how data is retrieved from the document and set inside it. Hence, the controller features two methods which allow to get and set data of the model using given:

Filtering

Properties

  • downcastDispatcher : DowncastDispatcher

    readonly

    Downcast dispatcher used by the get method. Downcast converters should be attached to it.

  • mapper : Mapper

    readonly

    Mapper used for the conversion. It has no permanent bindings, because they are created when getting data and cleared directly after the data are converted. However, the mapper is defined as a class property, because it needs to be passed to the DowncastDispatcher as a conversion API.

  • model : Model

    readonly

    Data model.

  • processor : DataProcessor

    readonly

    Data processor used during the conversion.

  • upcastDispatcher : UpcastDispatcher

    readonly

    Upcast dispatcher used by the set method. Upcast converters should be attached to it.

Methods

  • constructor( model, [ dataProcessor ] )

    Creates a data controller instance.

    Parameters

    model : Model

    Data model.

    [ dataProcessor ] : DataProcessor

    Data processor that should be used by the controller.

  • bind( bindProperties ) → Object

    mixed

    Binds obvervable properties to other objects implementing the Observable interface.

    Read more in the dedicated guide covering the topic of property bindings with some additional examples.

    Let's 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 another 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.

    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:

    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
  • destroy()

    Removes all event listeners set by the DataController.

  • 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).

  • get( [ options ] = { [options.rootName], [options.trim] } ) → String

    Returns the model's data converted by downcast dispatchers attached to downcastDispatcher and formatted by the data processor.

    Parameters

    [ options ] : Object
    Properties
    [ options.rootName ] : String

    Root name.

    Defaults to 'main'

    [ options.trim ] : String

    Whether returned data should be trimmed. This option is set to empty by default, which means whenever editor content is considered empty, an empty string will be returned. To turn off trimming completely use 'none'. In such cases exact content will be returned (for example <p>&nbsp;</p> for an empty editor).

    Defaults to 'empty'

    Returns

    String

    Output data.

  • init( data ) → Promise

    Sets initial input data parsed by the data processor and converted by the view-to-model converters. Initial data can be set only to document that version is equal 0.

    Note This method is decorated which is used by e.g. collaborative editing plugin that syncs remote data on init.

    When data is passed as a string it is initialized on a default main root:

    dataController.init( '<p>Foo</p>' ); // Initializes data on the `main` root.

    To initialize data on a different root or multiple roots at once, object containing rootName - data pairs should be passed:

    dataController.init( { main: '<p>Foo</p>', title: '<h1>Bar</h1>' } ); // Initializes data on the `main` and `title` roots.

    Parameters

    data : String | Object.<String, String>

    Input data as a string or an object containing rootName - data pairs to initialize data on multiple roots at once.

    Returns

    Promise

    Promise that is resolved after the data is set on the editor.

    Fires

  • 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 {}

  • parse( data, [ context ] ) → DocumentFragment

    Returns the data parsed by the data processor and then converted by upcast converters attached to the upcastDispatcher.

    Parameters

    data : String

    Data to parse.

    [ context ] : SchemaContextDefinition

    Base context in which the view will be converted to the model. See: convert.

    Defaults to '$root'

    Returns

    DocumentFragment

    Parsed data.

    Related:

  • set( data )

    mixed

    Sets input data parsed by the data processor and converted by the view-to-model converters. This method can be used any time to replace existing editor data by the new one without clearing the document history.

    This method also creates a batch with all the changes applied. If all you need is to parse data, use the parse method.

    When data is passed as a string it is set on a default main root:

    dataController.set( '<p>Foo</p>' ); // Sets data on the `main` root.

    To set data on a different root or multiple roots at once, object containing rootName - data pairs should be passed:

    dataController.set( { main: '<p>Foo</p>', title: '<h1>Bar</h1>' } ); // Sets data on the `main` and `title` roots.

    Parameters

    data : String | Object.<String, String>

    Input data as a string or an object containing rootName - data pairs to set data on multiple roots at once.

  • 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.

  • stringify( modelElementOrFragment ) → String

    Returns the content of the given model's element or model document fragment converted by the downcast converters attached to downcastDispatcher and formatted by the data processor.

    Parameters

    modelElementOrFragment : Element | DocumentFragment

    Element whose content will be stringified.

    Returns

    String

    Output data.

  • toModel( viewElementOrFragment, [ context ] ) → DocumentFragment

    Returns the result of the given view element or view document fragment converted by the view-to-model converters, wrapped by DocumentFragment.

    When marker elements were converted during the conversion process, it will be set as a document fragment's static markers map.

    Parameters

    viewElementOrFragment : Element | DocumentFragment

    Element or document fragment whose content will be converted.

    [ context ] : SchemaContextDefinition

    Base context in which the view will be converted to the model. See: convert.

    Defaults to '$root'

    Returns

    DocumentFragment

    Output document fragment.

  • toView( modelElementOrFragment ) → DocumentFragment

    Returns the content of the given model element or model document fragment converted by the downcast converters attached to downcastDispatcher to a view document fragment.

    Parameters

    modelElementOrFragment : Element | DocumentFragment

    Element or document fragment whose content will be converted.

    Returns

    DocumentFragment

    Output view DocumentFragment.

  • unbind( [ unbindProperties ] )

    mixed

    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 ] : String

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

  • _checkIfRootsExists( rootNames ) → Boolean

    private

    Checks if all provided root names are existing editor roots.

    Parameters

    rootNames : Array.<String>

    Root names to check.

    Returns

    Boolean

    Whether all provided root names are existing editor roots.

Events

  • 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.

  • init( eventInfo )

    Event fired after init() method has been run. It can be listened to to adjust/modify the initialisation flow. However, if the init event is stopped or prevented, the ready event should be fired manually.

    The init event is fired by decorated init method. See decorate for more information and samples.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

  • ready( eventInfo )

    Event fired once data initialisation has finished.

    Parameters

    eventInfo : EventInfo

    An object containing information about the fired event.

  • 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).

    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.