(function (global, factory) {
'use strict';
var built = factory(global);
/* istanbul ignore else */
Eif (typeof module === 'object' && module) {
module.exports = built;
}
/* istanbul ignore next */
if (typeof define === 'function' && define.amd) {
define(factory);
}
global.EventEmitter = built;
}(typeof global !== 'undefined' ? global : /* istanbul ignore next */ this, function (global) {
'use strict';
/**
* Creates an instance of EventEmitter class.
*
* @constructor
*/
function EventEmitter() {
this._events = {};
}
EventEmitter.prototype = {
constructor: EventEmitter,
/**
* Adds event listener to an event.
*
* @param {string} event The name of the event.
* @param {Function} callback Callback method to be invoked when event is being emitted.
*/
on: function (event, callback) {
var listeners = this._events[event] = this._events[event] || [];
listeners.push(callback);
},
/**
* Removes an event from the list of event listeners to some event.
*
* @param {string} event The name of the event.
* @param {function} callback Callback method to be removed from the list of listeners.
*/
off: function (event, callback) {
var listeners = this._events[event];
if (listeners) {
var callbackIndex = listeners.indexOf(callback);
if (callbackIndex > -1) {
listeners.splice(callbackIndex, 1);
} else {
console.warn('Off: callback was not removed: ' + callback.toString());
}
} else {
console.warn('Off: there are no listeners for event: ' + event);
}
},
/**
* Emits an event. The function calls all registered listeners in the order they have been added. The provided args
* param will be passed to each listener of the event.
*
* @param {string} event The name of the event.
* @param {object} args Object, which will be passed to the listener as only argument.
*/
emit: function (event, args) {
var listeners = this._events[event];
if (listeners) {
// Slicing is needed to prevent the following situation:
// A listener is being invoked. During its execution, it may
// remove itself from the list. In this case, for loop will
// be damaged, since i will be out of sync.
listeners = listeners.slice(0);
for (var i = 0; i < listeners.length; i++) {
var listener = listeners[i];
listener.call(listener, args);
}
} else {
console.warn('No listeners for event: ' + event);
}
}
};
return EventEmitter;
})); |