basic event emitter implementation for practice

emit.js

function EventEmitter() {
  this._events = {};
}

EventEmitter.prototype.on = function(event, func) {
  if (!this._events[event] || this._events === {}) {
    this._events[event] = func;
  } else if (this._events[event] && !(this._events[event] instanceof Array)) {
    var firstFunc = this._events[event];
    this._events[event] = [];
    this._events[event].push(firstFunc);
    this._events[event].push(func);
  } else if (this._events[event] && this._events instanceof Array) {
    this._events[event].push(func);
  }
};

EventEmitter.prototype.emit = function(event) {
  if (this._events[event] instanceof Array) {
    var eventArr = this._events[event];
    for (var i = 0; i < eventArr.length; i++) {
      var func = eventArr[i];
      func();
    }
  } else if (this._events[event] && !(this._events[event] instanceof Array)) {
    var firefunc = this._events[event];
    firefunc();
  }
};

EventEmitter.prototype.off = function(event) {
  delete this._events[event];
};

emitter = new EventEmitter();

emitter.on('hello', function() {
  console.log('hello fired!');
});

emitter.on('hello', function() {
  console.log('hola');
});

emitter.on('goodbye', function() {
  console.log('goodbye fired');
});

emitter.emit('hello');
emitter.emit('goodbye');

console.log(emitter._events.hello);
console.log(emitter._events.goodbye);

emitter.off('hello');
emitter.off('goodbye');

console.log(emitter._events.hello);
console.log(emitter._events.goodbye);