/** * @license Copyright (c) 2003-2015, CKSource - Frederico Knabben. All rights reserved. * For licensing, see LICENSE.md. */ 'use strict'; import Observer from './observer.js'; import DomEventData from './domeventdata.js'; /** * Base class for DOM event observers. This class handles * {@link engine.treeView.observer.Observer#observe adding} listeners to DOM elements, * {@link engine.treeView.observer.Observer#disable disabling} and * {@link engine.treeView.observer.Observer#enable re-enabling} events. * Child class needs to define * {@link engine.treeView.observer.DomEventObserver#domEventType DOM event type} and * {@link engine.treeView.observer.DomEventObserver#onDomEvent callback}. * * For instance: * * class ClickObserver extends DomEventObserver { * // It can also be defined as a normal property in the constructor. * get domEventType() { * return 'click'; * } * * onDomEvent( domEvt ) { * this.fire( 'click' ); * } * } * * @memberOf engine.treeView.observer * @extends engine.treeView.observer.Observer */ export default class DomEventObserver extends Observer { /** * Type of the DOM event the observer should listen on. Array of types can be defined * if the obsever should listen to multiple DOM events. * * @readonly * @member {String|Array.} engine.treeView.observer.DomEventObserver#domEventType */ /** * Callback which should be called when the DOM event occurred. Note that the callback will not be called if * observer {@link engine.treeView.observer.DomEventObserver#isEnabled is not enabled}. * * @see engine.treeView.observer.DomEventObserver#domEventType * @abstract * @method engine.treeView.observer.DomEventObserver#onDomEvent */ /** * @inheritDoc */ observe( domElement ) { const types = typeof this.domEventType == 'string' ? [ this.domEventType ] : this.domEventType; types.forEach( type => { domElement.addEventListener( type, domEvent => this.isEnabled && this.onDomEvent( domEvent ) ); } ); } /** * Calls {@link engine.treeView.TreeView#fire} if observer * {@link engine.treeView.observer.DomEventObserver#isEnabled is enabled}. * * @see engine.treeView.TreeView#fire * @param {String} eventType The event type (name). * @param {Event} domEvent The DOM event. * @param {Object} [additionalData] The additional data which should extend the * {@link engine.treeView.observer.DomEventData event data} object. */ fire( eventType, domEvent, additionalData ) { if ( this.isEnabled ) { this.treeView.fire( eventType, new DomEventData( this.treeView, domEvent, additionalData ) ); } } }