Model (ui)
@ckeditor/ckeditor5-ui/src/model
The base MVC model class.
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Properties
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[x: string] : unknownmodule:ui/model~Model#__index[0]
Methods
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constructor( [ attributes ], [ properties ] )module:ui/model~Model#constructorCreates a new Model instance.
Parameters
[ attributes ] : Record<string, unknown>The model state attributes to be defined during the instance creation.
[ properties ] : Record<string, unknown>The (out of state) properties to be appended to the instance during creation.
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Binds observable properties to other objects implementing the
Observableinterface.Read more in the dedicated guide covering the topic of property bindings with some additional examples.
Consider two objects: a
buttonand an associatedcommand(bothObservable).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.isEnabledinstantly equalscommand.isEnabled,- whenever
command.isEnabledchanges,button.isEnabledwill 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
buttonto multiple commands (alsoObservables) 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 : Array<string>Observable properties that will be bound to other observable(s).
Returns
MultiBindChainThe bind chain with the
to()andtoMany()methods.
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inherited
bind( bindProperty1, bindProperty2 ) → DualBindChain<K1, Model[ K1 ], K2, Model[ K2 ]>module:ui/model~Model#bind:DUAL_BINDBinds observable properties to other objects implementing the
Observableinterface.Read more in the dedicated guide covering the topic of property bindings with some additional examples.
Consider two objects: a
buttonand an associatedcommand(bothObservable).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.isEnabledinstantly equalscommand.isEnabled,- whenever
command.isEnabledchanges,button.isEnabledwill 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
buttonto multiple commands (alsoObservables) 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 );Type parameters
K1 : extends stringK2 : extends string
Parameters
bindProperty1 : K1Observable property that will be bound to other observable(s).
bindProperty2 : K2Observable property that will be bound to other observable(s).
Returns
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inherited
bind( bindProperty ) → SingleBindChain<K, Model[ K ]>module:ui/model~Model#bind:SINGLE_BINDBinds observable properties to other objects implementing the
Observableinterface.Read more in the dedicated guide covering the topic of property bindings with some additional examples.
Consider two objects: a
buttonand an associatedcommand(bothObservable).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.isEnabledinstantly equalscommand.isEnabled,- whenever
command.isEnabledchanges,button.isEnabledwill 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
buttonto multiple commands (alsoObservables) 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 );Type parameters
K : extends string
Parameters
bindProperty : KObservable property that will be bound to other observable(s).
Returns
SingleBindChain<K, Model[ K ]>The bind chain with the
to()andtoMany()methods.
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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 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 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 : stringName of the method to decorate.
Returns
void
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Delegates selected events to another
Emitter. For instance:emitterA.delegate( 'eventX' ).to( emitterB ); emitterA.delegate( 'eventX', 'eventY' ).to( emitterC );then
eventXis delegated (fired by)emitterBandemitterCalong withdata:emitterA.fire( 'eventX', data );and
eventYis delegated (fired by)emitterCalong withdata:emitterA.fire( 'eventY', data );Parameters
events : Array<string>Event names that will be delegated to another emitter.
Returns
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Fires an event, executing all callbacks registered for it.
The first parameter passed to callbacks is an
EventInfoobject, followed by the optionalargsprovided in thefire()method call.Type parameters
Parameters
eventOrInfo : GetNameOrEventInfo<TEvent>The name of the event or
EventInfoobject if event is delegated.args : TEvent[ 'args' ]Additional arguments to be passed to the callbacks.
Returns
GetEventInfo<TEvent>[ 'return' ]By default the method returns
undefined. However, the return value can be changed by listeners through modification of theevt.return's property (the event info is the first param of every callback).
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inherited
listenTo( emitter, event, callback, [ options ] ) → voidmodule:ui/model~Model#listenTo:BASE_EMITTERRegisters 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
firemethod.Type parameters
Parameters
emitter : EmitterThe object that fires the event.
event : TEvent[ 'name' ]The name of the event.
callback : GetCallback<TEvent>The function to be called on event.
[ options ] : GetCallbackOptions<TEvent>Additional options.
Returns
void
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Stops executing the callback on the given event. Shorthand for
this.stopListening( this, event, callback ).Parameters
event : stringThe name of the event.
callback : FunctionThe function to stop being called.
Returns
void
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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).Type parameters
Parameters
event : TEvent[ 'name' ]The name of the event.
callback : GetCallback<TEvent>The function to be called on event.
[ options ] : GetCallbackOptions<TEvent>Additional options.
Returns
void
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Registers a callback function to be executed on the next time the event is fired only. This is similar to calling
onfollowed byoffin the callback.Type parameters
Parameters
event : TEvent[ 'name' ]The name of the event.
callback : GetCallback<TEvent>The function to be called on event.
[ options ] : GetCallbackOptions<TEvent>Additional options.
Returns
void
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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-overrideerror if the observable instance already has a property with the given property name. This prevents from mistakenly overriding existing properties and methods, but means thatfoo.set( 'bar', 1 )may be slightly slower thanfoo.bar = 1.In TypeScript, those properties should be declared in class using
declarekeyword. In example:public declare myProp1: number; public declare myProp2: string; constructor() { this.set( { 'myProp1: 2, 'myProp2: 'foo' } ); }Parameters
values : objectAn object with
name=>valuepairs.
Returns
void
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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-overrideerror if the observable instance already has a property with the given property name. This prevents from mistakenly overriding existing properties and methods, but means thatfoo.set( 'bar', 1 )may be slightly slower thanfoo.bar = 1.In TypeScript, those properties should be declared in class using
declarekeyword. In example:public declare myProp: number; constructor() { this.set( 'myProp', 2 ); }Type parameters
K : extends string
Parameters
name : KThe property's name.
value : Model[ K ]The property's value.
Returns
void
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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 ] : stringThe 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 ofeventto all emitters.
Returns
void
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inherited
stopListening( [ emitter ], [ event ], [ callback ] ) → voidmodule:ui/model~Model#stopListening:BASE_STOPStops 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 ] : EmitterThe 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 fromemitter.[ callback ] : Function(Requires the
event) The function to be removed from the call list for the givenevent.
Returns
void
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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 : Array<string>Observable properties to be unbound. All the bindings will be released if no properties are provided.
Returns
void
Events
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inherited
change:{property}( eventInfo, name, value, oldValue )module:ui/model~Model#event:change:{property}Fired when a property changed value.
observable.set( 'prop', 1 ); observable.on<ObservableChangeEvent<number>>( '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 : EventInfoAn object containing information about the fired event.
name : stringThe property name.
value : TValueThe new property value.
oldValue : TValueThe previous property value.
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inherited
set:{property}( eventInfo, name, value, oldValue )module:ui/model~Model#event:set:{property}Fired when a property value is going to be set but is not set yet (before the
changeevent is fired).You can control the final value of the property by using the event's
returnproperty.observable.set( 'prop', 1 ); observable.on<ObservableSetEvent<number>>( '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<ObservableChangeEvent<number>>( '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 : EventInfoAn object containing information about the fired event.
name : stringThe property name.
value : TValueThe new property value.
oldValue : TValueThe previous property value.
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