var events = require('events');
var eventEmitter = new events.EventEmitter();
var connectHandler = function connected() {
     console.log('connection successful.');
     eventEmitter.emit('data_received');
}

eventEmitter.on('connection', connectHandler);

eventEmitter.on('data_received', function(){
    console.log('data received successfully.');
});

eventEmitter.emit('connection');
console.log("Program Ended.");