How Marius understood Node's single threaded asynchronous-ness & events

events.js

var events = require('events');
var eventEmitter = new events.EventEmitter()

function mainLoop() {
  console.log('starting application');
  eventEmitter.emit('AppStart');

  console.log('Running App');
  eventEmitter.emit('AppRun');

  console.log('Stopping App');
  eventEmitter.emit('AppStop');
}

function onAppStart() {
  console.log('»1 Handling App start Event');
}

function onAppRun() {
  console.log('»2 Handling App run Event');
  setTimeout(function() {
    console.log('»3 » Marius runs here!');
  }, 5000);
}

function onAppStop() {
  console.log('»4 Handling App Stop event');
}

eventEmitter.on('AppStart', onAppStart);
eventEmitter.on('AppRun', onAppRun);
eventEmitter.on('AppStop', onAppStop);

function onAppStart () {
  console.log('»1 » » start, start, start!!!');
}

mainLoop();

output.sh

[node-network (master)]$ node events.js 
Starting application
»1 » » Start: go, go, go!!!
Running Application
»2 Handling Application run Event
Stopping Application
»4 Handling Application Stop event
»3 » Marius runs here!