ContextWatchdog

The watched item.

The context instance. Keep in mind that this property might be changed when the context watchdog restarts, so do not keep this instance internally. Always operate on the ContextWatchdog#context property.

An array of crashes saved as an object with the following properties:

• message: String,
• stack: String,
• date: Number,
• filename: String | undefined,
• lineno: Number | undefined,
• colno: Number | undefined,

Specifies the state of the item watched by the watchdog. The state can be one of the following values:

• initializing – Before the first initialization, and after crashes, before the item is ready.
• ready – A state when the user can interact with the item.
• crashed – A state when an error occurs. It quickly changes to initializing or crashedPermanently depending on how many and how frequent errors have been caught recently.
• crashedPermanently – A state when the watchdog stops reacting to errors and keeps the item it is watching crashed,
• destroyed – A state when the item is manually destroyed by the user after calling watchdog.destroy().

The creation method.

Related:

• ContextWatchdog#setCreator

The destruction method.

Related:

• ContextWatchdog#setDestructor

A map of internal watchdogs for added items.

An action queue, which is used to handle async functions queuing.

The current context instance.

The configuration for the Context.

Context properties (nodes/references) that are gathered during the initial context creation and are used to distinguish the origin of an error.

The watchdog configuration.

The context watchdog class constructor.

const watchdog = new ContextWatchdog( Context );

await watchdog.create( contextConfiguration );

await watchdog.add( item );

See the Watchdog feature guide to learn more how to use this feature.

Type parameters

TContext : extends [object Object] = Context

Parameters

Context : object

The Context class.

Properties

Context.create : Promise<TContext>

watchdogConfig : WatchdogConfig

The watchdog configuration.

Defaults to {}

Adds items to the watchdog. Once created, instances of these items will be available using the getItem method.

Items can be passed together as an array of objects:

await watchdog.add( [ {
	id: 'editor1',
	type: 'editor',
	sourceElementOrData: document.querySelector( '#editor' ),
	config: {
		plugins: [ Essentials, Paragraph, Bold, Italic ],
		toolbar: [ 'bold', 'italic', 'alignment' ]
	},
	creator: ( element, config ) => ClassicEditor.create( element, config )
} ] );

Or one by one as objects:

await watchdog.add( {
	id: 'editor1',
	type: 'editor',
	sourceElementOrData: document.querySelector( '#editor' ),
	config: {
		plugins: [ Essentials, Paragraph, Bold, Italic ],
		toolbar: [ 'bold', 'italic', 'alignment' ]
	},
	creator: ( element, config ) => ClassicEditor.create( element, config )
] );

Then an instance can be retrieved using the getItem method:

const editor1 = watchdog.getItem( 'editor1' );

Note that this method can be called multiple times, but for performance reasons it is better to pass all items together.

Parameters

itemConfigurationOrItemConfigurations : ArrayOrItem<ContextWatchdogItemConfiguration>

An item configuration object or an array of item configurations.

Returns

Promise<unknown>

Initializes the context watchdog. Once it is created, the watchdog takes care about recreating the context and the provided items, and starts the error handling mechanism.

await watchdog.create( {
	plugins: []
} );

Parameters

contextConfig : ContextConfig

The context configuration. See Context.

Defaults to {}

Returns

Promise<unknown>

Destroys the context watchdog and all added items. Once the context watchdog is destroyed, new items cannot be added.

await watchdog.destroy();

Returns

Promise<unknown>

Returns an item instance with the given itemId.

const editor1 = watchdog.getItem( 'editor1' );

Parameters

itemId : string

The item ID.

Returns

unknown

The item instance or undefined if an item with a given ID has not been found.

Gets the state of the given item. See state for a list of available states.

const editor1State = watchdog.getItemState( 'editor1' );

Parameters

itemId : string

Item ID.

Returns

WatchdogState

The state of the item.

Stops listening to the specified event name by removing the callback from event listeners.

Note that this method differs from the CKEditor 5's default EventEmitterMixin implementation.

Parameters

eventName : keyof WatchdogEventMap

The event name.

callback : unknown

A callback which will be removed from event listeners.

Returns

void

Starts listening to a specific event name by registering a callback that will be executed whenever an event with a given name fires.

Note that this method differs from the CKEditor 5's default EventEmitterMixin implementation.

Type parameters

K : extends keyof WatchdogEventMap

Parameters

eventName : K

The event name.

callback : WatchdogEventCallback<K>

A callback which will be added to event listeners.

Returns

void

Removes and destroys item(s) with given ID(s).

await watchdog.remove( 'editor1' );

Or

await watchdog.remove( [ 'editor1', 'editor2' ] );

Parameters

itemIdOrItemIds : ArrayOrItem<string>

Item ID or an array of item IDs.

Returns

Promise<unknown>

Sets the function that is responsible for the context creation. It expects a function that should return a promise (or undefined).

watchdog.setCreator( config => Context.create( config ) );

Parameters

creator : ( config: ContextConfig ) => Promise<TContext>

Returns

void

Sets the function that is responsible for the context destruction. Overrides the default destruction function, which destroys only the context instance. It expects a function that should return a promise (or undefined).

watchdog.setDestructor( context => {
	// Do something before the context is destroyed.

	return context
		.destroy()
		.then( () => {
			// Do something after the context is destroyed.
		} );
} );

Parameters

destructor : ( context: Context ) => Promise<unknown>

Returns

void

Checks whether an error comes from the context instance and not from the item instances.

Parameters

error : CKEditorError

Returns

boolean

Fires an event with a given event name and arguments.

Note that this method differs from the CKEditor 5's default EventEmitterMixin implementation.

Type parameters

K : extends keyof WatchdogEventMap

Parameters

eventName : K

args : WatchdogEventArgs<K>

Returns

void

Returns the watchdog for a given item ID.

Parameters

itemId : string

Item ID.

Returns

Watchdog

Restarts the context watchdog.

Returns

Promise<unknown>

Starts error handling by attaching global error handlers.

Returns

void

Stops error handling by detaching global error handlers.

Returns

void

Initializes the context watchdog.

Returns

Promise<unknown>

Destroys the context instance and all added items.

Returns

Promise<unknown>

Fired when a new CKEditorError error connected to the watchdog instance occurs and the watchdog will react to it.

watchdog.on( 'error', ( evt, { error, causesRestart } ) => {
	console.log( 'An error occurred.' );
} );

Parameters

eventInfo : EventInfo

An object containing information about the fired event.

<anonymous> : WatchdogErrorEventData

Fired when a new error occurred in one of the added items.

watchdog.on( 'itemError', ( evt, { error, itemId } ) => {
	console.log( `An error occurred in an item with the '${ itemId }' ID.` );
} );

Parameters

eventInfo : EventInfo

An object containing information about the fired event.

<anonymous> : ContextWatchdogItemErrorEventData

Fired after an item has been restarted.

	watchdog.on( 'itemRestart', ( evt, { itemId } ) => {
		console.log( 'An item with with the '${ itemId }' ID has been restarted.' );
	} );

Parameters

eventInfo : EventInfo

An object containing information about the fired event.

<anonymous> : ContextWatchdogItemRestartEventData

Fired after the watchdog restarts the context and the added items because of a crash.

watchdog.on( 'restart', () => {
	console.log( 'The context has been restarted.' );
} );

Parameters

eventInfo : EventInfo

An object containing information about the fired event.

Fired when the watchdog state changed.

Parameters

eventInfo : EventInfo

An object containing information about the fired event.