recipe to create event emitting class in nodejs

node_even_listener.js

// created from example at http://thejackalofjavascript.com/node-js-design-patterns/
// and using nodejs.org docs

var EventEmitter = require('events').EventEmitter;
var util = require('util');


function Batter(name) {
  this.name = name;
  // initialize properties from EventEmitter on this instance
  EventEmitter.call(this);

  this.swing = function() { 
    console.log('function swing() called, will emit strike event'); 
    this.emit('swing');
  }
}

// make Batter inherit functions from EventEmitter (on, emit, ...)
// this is direct prototype asignment way - tested and works
//Batter.prototype = EventEmitter.prototype;
// but this is the documented way https://nodejs.org/api/events.html
util.inherits(Batter, events.EventEmitter);

// create new istance of batter
var b = new Batter('Babe Ruth');

b.on('swing', function() { console.log('It is a Strrikkkeee!!!!'); });

// now call function
// that emits 'swing'
// and this calls on('swing') callback
b.swing();