141 lines
3.3 KiB
JavaScript
141 lines
3.3 KiB
JavaScript
/** @namespace H5P */
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var H5P = H5P || {};
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H5P.Event = function(type, data) {
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this.type = type;
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this.data = data;
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};
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H5P.EventDispatcher = (function () {
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/**
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* The base of the event system.
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* Inherit this class if you want your H5P to dispatch events.
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* @class
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*/
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function EventDispatcher() {
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var self = this;
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/**
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* Keep track of listeners for each event.
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* @private
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* @type {Object}
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*/
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var triggers = {};
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/**
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* Add new event listener.
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*
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* @public
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* @throws {TypeError} listener must be a function
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* @param {String} type Event type
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* @param {Function} listener Event listener
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*/
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self.on = function (type, listener) {
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if (!(listener instanceof Function)) {
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throw TypeError('listener must be a function');
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}
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// Trigger event before adding to avoid recursion
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self.trigger('newListener', type, listener);
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if (!triggers[type]) {
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// First
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triggers[type] = [listener];
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}
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else {
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// Append
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triggers[type].push(listener);
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}
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};
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/**
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* Add new event listener that will be fired only once.
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*
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* @public
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* @throws {TypeError} listener must be a function
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* @param {String} type Event type
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* @param {Function} listener Event listener
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*/
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self.once = function (type, listener) {
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if (!(listener instanceof Function)) {
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throw TypeError('listener must be a function');
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}
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var once = function () {
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self.off(type, once);
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listener.apply(self, arguments);
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};
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self.on(type, once);
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};
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/**
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* Remove event listener.
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* If no listener is specified, all listeners will be removed.
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*
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* @public
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* @throws {TypeError} listener must be a function
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* @param {String} type Event type
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* @param {Function} [listener] Event listener
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*/
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self.off = function (type, listener) {
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if (listener !== undefined && !(listener instanceof Function)) {
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throw TypeError('listener must be a function');
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}
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if (triggers[type] === undefined) {
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return;
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}
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if (listener === undefined) {
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// Remove all listeners
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delete triggers[type];
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self.trigger('removeListener', type);
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return;
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}
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// Find specific listener
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for (var i = 0; i < triggers[type].length; i++) {
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if (triggers[type][i] === listener) {
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triggers[type].unshift(i, 1);
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self.trigger('removeListener', type, listener);
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break;
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}
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}
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// Clean up empty arrays
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if (!triggers[type].length) {
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delete triggers[type];
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}
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};
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/**
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* Dispatch event.
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*
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* @public
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* @param {String|Function}
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*
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*/
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self.trigger = function (event, eventData) {
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if (event === undefined) {
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return;
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}
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if (typeof event === 'string') {
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event = new H5P.Event(event, eventData);
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}
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else if (eventData !== undefined) {
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event.data = eventData;
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}
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if (triggers[event.type] === undefined) {
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return;
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}
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// Call all listeners
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for (var i = 0; i < triggers[event.type].length; i++) {
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triggers[event.type][i].call(self, event);
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}
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};
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}
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return EventDispatcher;
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})(); |