80 lines
2.7 KiB
JavaScript
80 lines
2.7 KiB
JavaScript
/*
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* Implements EventTarget
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* https://developer.mozilla.org/en-US/docs/Web/API/EventTarget
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*/
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;(function () {
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'use strict';
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window.textsecure = window.textsecure || {};
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function EventTarget() {
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}
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EventTarget.prototype = {
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constructor: EventTarget,
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dispatchEvent: function(ev) {
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if (!(ev instanceof Event)) {
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throw new Error('Expects an event');
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}
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if (this.listeners === null || typeof this.listeners !== 'object') {
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this.listeners = {};
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}
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var listeners = this.listeners[ev.type];
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var results = [];
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if (typeof listeners === 'object') {
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for (var i = 0, max = listeners.length; i < max; i += 1) {
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var listener = listeners[i];
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if (typeof listener === 'function') {
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results.push(listener.call(null, ev));
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}
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}
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}
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return results;
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},
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addEventListener: function(eventName, callback) {
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if (typeof eventName !== 'string') {
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throw new Error('First argument expects a string');
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}
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if (typeof callback !== 'function') {
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throw new Error('Second argument expects a function');
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}
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if (this.listeners === null || typeof this.listeners !== 'object') {
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this.listeners = {};
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}
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var listeners = this.listeners[eventName];
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if (typeof listeners !== 'object') {
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listeners = [];
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}
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listeners.push(callback);
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this.listeners[eventName] = listeners;
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},
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removeEventListener: function(eventName, callback) {
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if (typeof eventName !== 'string') {
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throw new Error('First argument expects a string');
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}
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if (typeof callback !== 'function') {
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throw new Error('Second argument expects a function');
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}
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if (this.listeners === null || typeof this.listeners !== 'object') {
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this.listeners = {};
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}
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var listeners = this.listeners[eventName];
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if (typeof listeners === 'object') {
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for (var i=0; i < listeners.length; ++ i) {
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if (listeners[i] === callback) {
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listeners.splice(i, 1);
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return;
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}
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}
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}
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this.listeners[eventName] = listeners;
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},
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extend: function(obj) {
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for (var prop in obj) {
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this[prop] = obj[prop];
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}
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return this;
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}
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};
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textsecure.EventTarget = EventTarget;
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}());
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