basic event emitter

//index.js
var Emitter = require('./emitter');

var emtr = new Emitter();

emtr.on('greet', function(){
  console.log('Hello 1');
});

emtr.on('greet', function(){
  console.log('Hello 2');
});

console.log('Hello 3');

emtr.emit('greet');

//emitter.js
function Emitter(){
  this.events = {};
}

Emitter.prototype.on = function(type, listener){
  this.events[type] = this.events[type] || [];
  this.events[type].push(listener);
}

Emitter.prototype.emit = function(type, listener) {
  if (this.events[type]) {
    this.events[type].forEach(function(listener) {
      listener();
    });
  }
}

Emitter.prototype.emit = function(type){
  if (this.events[type]) {
    this.events[type].forEach(function(listener){
      listener();
    });
  }
}

module.exports = Emitter;