/*!
* The MIT License (MIT)
*
* Copyright (c) 2016 Mykhailo Stadnyk <mikhus@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/**
* Class EventEmitter - base event manager
*/
export default class EventEmitter {
/**
* @constructor
*/
constructor() {
this._events = {};
this.addListener = this.on;
this.removeListener = this.off;
}
/**
* Returns all event listeners
*
* @return {object}
*/
get listeners() {
return this._events;
}
/**
* Emits given event bypassing to each registered handler given args
*
* @param {string} event
* @param {...*} args
*/
emit(event, ...args) {
if (this._events[event]) {
let i = 0;
let s = this._events[event].length;
for (; i < s; i++) {
this._events[event][i] &&
this._events[event][i].apply(this, args);
}
}
}
/**
* Registers given handler for given event to be called only once when
* event is emitted
*
* @param {string} event
* @param {...function} handlers
*/
once(event, ...handlers) {
let i = 0;
let s = handlers.length;
let self = this;
for (; i < s; i++) {
let handler = handlers[i];
let wrapper = function() {
self.off(event, wrapper);
handler.apply(self, arguments);
};
handlers[i] = wrapper;
}
this.on.apply(this, [event].concat(handlers));
}
/**
* Registers given handlers for a given events to be called each time event
* is emitted
*
* @param {string} event
* @param {...function} handlers
*/
on(event, ...handlers) {
if (!this._events[event]) {
this._events[event] = [];
}
let i = 0;
let s = handlers.length;
for (; i < s; i++) {
this._events[event].push(handlers[i]);
}
}
/**
* Un-registers previously registered event handlers
*
* @param {string} event
* @param {...function} handlers
*/
off(event, ...handlers) {
if (!this._events[event]) {
return ;
}
let i = 0;
let s = handlers.length;
for (; i < s; i++) {
let handler = handlers[i];
let index;
while (~(index = this._events[event].indexOf(handler))) {
this._events[event].splice(index, 1);
}
}
}
/**
* Removes all listeners for a given event
*
* @param {string} event
*/
removeAllListeners(event) {
delete this._events[event];
}
}
module.exports = EventEmitter;