# ShadowRootRegistry

class

Keeps track of the shadow roots hosting a set of registered DOM nodes (for example an editor UI's editables, toolbars and menu bars, or a feature's own UI), so that consumers can, for instance, inject styles or listeners into every shadow root those nodes currently live in.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L22)

<a id="properties">

## Properties

<a id="member-_rootsByNode">

### `_rootsByNode: Map<Node, Array<ShadowRoot>>` _(private)_

The shadow roots hosting each registered node, as of the last time that node was looked at. Empty for a node that was detached or lived in the light DOM then. Re-derived for every node by each [`refresh`](#function-refresh), so a node that has since been attached, or moved to another tree, is picked up. The union of the values is [`getShadowRoots`](#function-getShadowRoots).

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L29)

<a id="methods">

## Methods

<a id="function-constructor">

### `constructor( args )` _(inherited)_

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/mix.ts#L57)

#### Parameters

* `args: [ ]`

<a id="function-delegate">

### `delegate( events ) → EmitterMixinDelegateChain` _(inherited)_

Delegates selected events to another [`Emitter`](module_utils_emittermixin-Emitter.md). For instance:

```typescript
emitterA.delegate( 'eventX' ).to( emitterB );
emitterA.delegate( 'eventX', 'eventY' ).to( emitterC );
```

then `eventX` is delegated (fired by) `emitterB` and `emitterC` along with `data`:

```typescript
emitterA.fire( 'eventX', data );
```

and `eventY` is delegated (fired by) `emitterC` along with `data`:

```typescript
emitterA.fire( 'eventY', data );
```

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L539)

#### Parameters

* `events: Array<string>`

  Event names that will be delegated to another emitter.

#### Returns

* `EmitterMixinDelegateChain`

<a id="function-fire">

### `fire( eventOrInfo, args ) → GetEventInfo<TEvent>[ 'return' ]` _(inherited)_

Fires an event, executing all callbacks registered for it.

The first parameter passed to callbacks is an [`EventInfo`](module_utils_eventinfo-EventInfo.md) object, followed by the optional `args` provided in the `fire()` method call.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L512)

#### Type parameters

* `TEvent: extends BaseEvent`

  The type describing the event. See [`BaseEvent`](module_utils_emittermixin-BaseEvent.md).

#### Parameters

* `eventOrInfo: GetNameOrEventInfo<TEvent>`

  The name of the event or `EventInfo` object 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 the [`evt.return`](module_utils_eventinfo-EventInfo.md#member-return)'s property (the event info is the first param of every callback).

<a id="function-getShadowRoots">

### `getShadowRoots() → Set<ShadowRoot>`

Returns the shadow roots currently hosting at least one registered node.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L34)

#### Returns

* `Set<ShadowRoot>`

<a id="function-listenTo:BASE_EMITTER">

### `listenTo( emitter, event, callback, options? ) → void` _(inherited)_

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.

```typescript
// 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](module_utils_eventinfo-EventInfo.md#member-stop) and set the [return value](module_utils_eventinfo-EventInfo.md#member-return) of the [`fire`](#function-fire) method.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L475)

#### Type parameters

* `TEvent: extends BaseEvent`

  The type describing the event. See [`BaseEvent`](module_utils_emittermixin-BaseEvent.md).

#### Parameters

* `emitter: Emitter`

  The 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`

<a id="function-off">

### `off( event, callback ) → void` _(inherited)_

Stops executing the callback on the given event. Shorthand for [`this.stopListening( this, event, callback )`](#function-stopListening:BASE_STOP).

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L444)

#### Parameters

* `event: string`

  The name of the event.

* `callback: Function`

  The function to stop being called.

#### Returns

* `void`

<a id="function-on">

### `on( event, callback, options? ) → void` _(inherited)_

Registers a callback function to be executed when an event is fired.

Shorthand for [`this.listenTo( this, event, callback, options )`](#function-listenTo:BASE_EMITTER) (it makes the emitter listen on itself).

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L416)

#### Type parameters

* `TEvent: extends BaseEvent`

  The type descibing the event. See [`BaseEvent`](module_utils_emittermixin-BaseEvent.md).

#### 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`

<a id="function-once">

### `once( event, callback, options? ) → void` _(inherited)_

Registers a callback function to be executed on the next time the event is fired only. This is similar to calling [`on`](#function-on) followed by [`off`](#function-off) in the callback.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L431)

#### Type parameters

* `TEvent: extends BaseEvent`

  The type descibing the event. See [`BaseEvent`](module_utils_emittermixin-BaseEvent.md).

#### 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`

<a id="function-refresh">

### `refresh() → void`

Re-derives the shadow roots of every registered node, firing [event-add](#event-add) for the roots that started hosting one and [event-remove](#event-remove) for those that stopped.

Call it whenever a registered node may have been attached, detached, or moved – for example on every editor UI update. Nodes are re-derived rather than resolved once, because the tree a node lives in is not fixed: an editable mounted by the integrator after the editor was created, or moved into a fullscreen container in another tree, ends up somewhere its roots were never derived from.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L87)

#### Returns

* `void`

<a id="function-registerNode">

### `registerNode( node ) → void`

Registers a node, so the shadow roots hosting it become a part of [`getShadowRoots`](#function-getShadowRoots).

The node does not have to be attached to the DOM yet; while it is not, it simply contributes no shadow root. The next [`refresh`](#function-refresh) picks it up once it is attached.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L52)

#### Parameters

* `node: Node`

#### Returns

* `void`

<a id="function-stopDelegating">

### `stopDelegating( event?, emitter? ) → void` _(inherited)_

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.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L552)

#### 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.

#### Returns

* `void`

<a id="function-stopListening:BASE_STOP">

### `stopListening( emitter?, event?, callback? ) → void` _(inherited)_

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.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/emittermixin.ts#L497)

#### 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`.

#### Returns

* `void`

<a id="function-unregisterNode">

### `unregisterNode( node ) → void`

Unregisters a previously [registered](#function-registerNode) node. Shadow roots that no longer host any registered node stop being a part of [`getShadowRoots`](#function-getShadowRoots).

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L67)

#### Parameters

* `node: Node`

#### Returns

* `void`

<a id="function-destroy">

### `destroy() → void` _(internal)_

Unregisters every currently registered node at once, firing [event-remove](#event-remove) for every shadow root that consequently stops being tracked.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L103)

#### Returns

* `void`

<a id="function-_fireRootChanges">

### `_fireRootChanges( previousRoots ) → void` _(private)_

Fires [event-add](#event-add) and [event-remove](#event-remove) for the difference between the given set of tracked shadow roots and the current one.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L114)

#### Parameters

* `previousRoots: Set<ShadowRoot>`

#### Returns

* `void`

<a id="events">

## Events

<a id="event-add">

### `add( eventInfo, root )`

Fired when a shadow root starts hosting a registered node.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L218)

#### Parameters

* `eventInfo: EventInfo`

  An object containing information about the fired event.

* `root: ShadowRoot`

  The shadow root that started being tracked.

<a id="event-remove">

### `remove( eventInfo, root )`

Fired when a shadow root no longer hosts any registered node.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-utils/src/dom/shadowrootregistry.ts#L229)

#### Parameters

* `eventInfo: EventInfo`

  An object containing information about the fired event.

* `root: ShadowRoot`

  The shadow root that stopped being tracked.

---

Full index of the CKEditor 5 API reference: [llms.txt](llms.txt)