michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: const { Trait } = require("../light-traits");
michael@0: const { removeListener, on } = require("../../dom/events");
michael@0: 
michael@0: /**
michael@0:  * Trait may be used for building objects / composing traits that wish to handle
michael@0:  * multiple dom events from multiple event targets in one place. Event targets
michael@0:  * can be added / removed by calling `observe / ignore` methods. Composer should
michael@0:  * provide array of event types it wishes to handle as property
michael@0:  * `supportedEventsTypes` and function for handling all those events as
michael@0:  * `handleEvent` property.
michael@0:  */
michael@0: exports.DOMEventAssembler = Trait({
michael@0:   /**
michael@0:    * Function that is supposed to handle all the supported events (that are
michael@0:    * present in the `supportedEventsTypes`) from all the observed
michael@0:    * `eventTargets`.
michael@0:    * @param {Event} event
michael@0:    *    Event being dispatched.
michael@0:    */
michael@0:   handleEvent: Trait.required,
michael@0:   /**
michael@0:    * Array of supported event names.
michael@0:    * @type {String[]}
michael@0:    */
michael@0:   supportedEventsTypes: Trait.required,
michael@0:   /**
michael@0:    * Adds `eventTarget` to the list of observed `eventTarget`s. Listeners for
michael@0:    * supported events will be registered on the given `eventTarget`.
michael@0:    * @param {EventTarget} eventTarget
michael@0:    */
michael@0:   observe: function observe(eventTarget) {
michael@0:     this.supportedEventsTypes.forEach(function(eventType) {
michael@0:       on(eventTarget, eventType, this);
michael@0:     }, this);
michael@0:   },
michael@0:   /**
michael@0:    * Removes `eventTarget` from the list of observed `eventTarget`s. Listeners
michael@0:    * for all supported events will be unregistered from the given `eventTarget`.
michael@0:    * @param {EventTarget} eventTarget
michael@0:    */
michael@0:   ignore: function ignore(eventTarget) {
michael@0:     this.supportedEventsTypes.forEach(function(eventType) {
michael@0:       removeListener(eventTarget, eventType, this);
michael@0:     }, this);
michael@0:   }
michael@0: });