Super simple event emitter

simple-event-emitter.js

"use strict"

function EventEmitter() {
    this._events = Object.create(null)
}

EventEmitter.prototype.on = function (event, func) {
    var handlers = this._events[event] = this._events[event] || []
    if (handlers.indexOf(func) < 0) handlers.push(func)
}

EventEmitter.prototype.off = function (event, func) {
    if (this._events[event] == null) return
    var index = this._events[event].indexOf(func)
    if (index >= 0) this._events[event].splice(index, 1)
}

EventEmitter.prototype.emit = function (event) {
    var handlers = this._events[event]
    if (handlers == null) return
    var args = [].slice.call(arguments, 1)
    for (var i = 0; i < handlers.length; i++) handlers[i].apply(void 0, args)
}