Document (engine/model)
@ckeditor/ckeditor5-engine/src/model/document
Data model's document. It contains the model's structure, its selection and the history of changes.
Read more about working with the model in introduction to the the editing engine's architecture.
Usually, the document contains just one root element, so
you can retrieve it by just calling getRoot without specifying its name:
model.document.getRoot(); // -> returns the main rootHowever, the document may contain multiple roots – e.g. when the editor has multiple editable areas (e.g. a title and a body of a message).
Filtering
Properties
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The model differ object. Its role is to buffer changes done on the model document and then calculate a diff of those changes.
-
graveyard : RootElementreadonly
The graveyard tree root. A document always has a graveyard root that stores removed nodes.
-
The document's history.
-
The model that the document is a part of.
-
roots : Collectionreadonly
A list of roots that are owned and managed by this document. Use
createRootandgetRootto manipulate it. -
selection : DocumentSelectionreadonly
The selection in this document.
-
version : NumberThe document version. It starts from
0and every operation increases the version number. It is used to ensure that operations are applied on a proper document version.If the base version does not match the document version, a model-document-applyOperation-wrong-version error is thrown.
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_hasSelectionChangedFromTheLastChangeBlock : Booleanprivate
A boolean indicates whether the selection has changed until
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_postFixers : Set.<Function>private
Post-fixer callbacks registered to the model document.
Methods
-
Creates an empty document instance with no
roots(other than the graveyard root). -
createRoot( [ elementName ], [ rootName ] ) → RootElementCreates a new root.
Parameters
[ elementName ] : StringThe element name. Defaults to
'$root'which also has some basic schema defined ($blocks are allowed inside the$root). Make sure to define a proper schema if you use a different name.Defaults to
'$root'[ rootName ] : StringA unique root name.
Defaults to
'main'
Returns
RootElementThe created root.
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delegate( events ) → EmitterMixinDelegateChainmixed
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 : StringEvent names that will be delegated to another emitter.
Returns
-
destroy()Removes all event listeners set by the document instance.
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fire( eventOrInfo, [ args ] ) → *mixed
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.Parameters
eventOrInfo : String | EventInfoThe name of the event or
EventInfoobject 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 theevt.return's property (the event info is the first param of every callback).
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getRoot( [ name ] ) → RootElement | nullReturns a root by its name.
Parameters
[ name ] : StringA unique root name.
Defaults to
'main'
Returns
RootElement | nullThe root registered under a given name or
nullwhen there is no root with the given name.
-
getRootNames() → Array.<String>Returns an array with names of all roots (without the
graveyard) added to the document.Returns
Array.<String>Roots names.
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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
firemethod.Parameters
emitter : EmitterThe object that fires the event.
event : StringThe name of the event.
callback : functionThe function to be called on event.
[ options ] : ObjectAdditional options.
Properties[ options.priority ] : PriorityString | NumberThe 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 : StringThe name of the event.
callback : functionThe function to stop being called.
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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 : StringThe name of the event.
callback : functionThe function to be called on event.
[ options ] : ObjectAdditional options.
Properties[ options.priority ] : PriorityString | NumberThe 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
onfollowed byoffin the callback.Parameters
event : StringThe name of the event.
callback : functionThe function to be called on event.
[ options ] : ObjectAdditional options.
Properties[ options.priority ] : PriorityString | NumberThe 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
{}
-
registerPostFixer( postFixer )Used to register a post-fixer callback. A post-fixer mechanism guarantees that the features will operate on a correct model state.
An execution of a feature may lead to an incorrect document tree state. The callbacks are used to fix the document tree after it has changed. Post-fixers are fired just after all changes from the outermost change block were applied but before the change event is fired. If a post-fixer callback made a change, it should return
true. When this happens, all post-fixers are fired again to check if something else should not be fixed in the new document tree state.As a parameter, a post-fixer callback receives a writer instance connected with the executed changes block. Thanks to that, all changes done by the callback will be added to the same batch (and undo step) as the original changes. This makes post-fixer changes transparent for the user.
An example of a post-fixer is a callback that checks if all the data were removed from the editor. If so, the callback should add an empty paragraph so that the editor is never empty:
document.registerPostFixer( writer => { const changes = document.differ.getChanges(); // Check if the changes lead to an empty root in the editor. for ( const entry of changes ) { if ( entry.type == 'remove' && entry.position.root.isEmpty ) { writer.insertElement( 'paragraph', entry.position.root, 0 ); // It is fine to return early, even if multiple roots would need to be fixed. // All post-fixers will be fired again, so if there are more empty roots, those will be fixed, too. return true; } } } );Parameters
postFixer : function
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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 ] : 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.
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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 ] : 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.
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toJSON() → ObjectA custom
toJSON()method to solve child-parent circular dependencies.Returns
ObjectA clone of this object with the document property changed to a string.
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_getDefaultRange() → Rangeprotected
Returns the default range for this selection. The default range is a collapsed range that starts and ends at the beginning of this selection's document default root.
Returns
-
_getDefaultRoot() → RootElementprotected
Returns the default root for this document which is either the first root that was added to the document using
createRootor the graveyard root if no other roots were created.Returns
RootElementThe default root for this document.
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_handleChangeBlock( writer )protected
Check if there were any changes done on document, and if so, call post-fixers, fire
changeevent for features and conversion and then reset the differ. Firechange:dataevent when at least one operation or buffered marker changes the data. -
_hasDocumentChangedFromTheLastChangeBlock() → Booleanprotected
Returns whether there is a buffered change or if the selection has changed from the last
enqueueChange()block orchange()block.Returns
BooleanReturns
trueif document has changed from the lastchange()orenqueueChange()block.
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_callPostFixers( writer )private
Performs post-fixer loops. Executes post-fixer callbacks as long as none of them has done any changes to the model.
Parameters
writer : WriterThe writer on which post-fixer callbacks will be called.
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_validateSelectionRange( range ) → Booleanprivate
Checks whether a given range is a valid range for the document's selection.
Events
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change( eventInfo, batch )Fired after each
enqueueChange()block or the outermostchange()block was executed and the document was changed during that block's execution.The changes which this event will cover include:
- document structure changes,
- selection changes,
- marker changes.
If you want to be notified about all these changes, then simply listen to this event like this:
model.document.on( 'change', () => { console.log( 'The document has changed!' ); } );If, however, you only want to be notified about the data changes, then use the change:data event, which is fired for document structure changes and marker changes (which affects the data).
model.document.on( 'change:data', () => { console.log( 'The data has changed!' ); } );Parameters
-
change:data( eventInfo, batch )It is a narrower version of the
event-changeevent. It is fired for changes which affect the editor data. This is:- document structure changes,
- marker changes (which affects the data).
If you want to be notified about the data changes, then listen to this event:
model.document.on( 'change:data', () => { console.log( 'The data has changed!' ); } );If you would like to listen to all document changes, then check out the change event.
Parameters