async test - It's a bad .JS. Don't use this scenario in a real server. #devsample

async_test.js

/* async test - It's a bad .JS. Don't use this scenario in a real server.
 * 1. The function1 saved the 'callback' and call it when the 'connect' is emitted
 * 2. The function3 will be triggered again when the connect event happended. 
 */
'use strict';

var events = require("events"),
    servEvt = new events.EventEmitter();


function function1(callback) {
    console.log('function1');
    servEvt.on('connect', function () {
        callback();
    });
}

function function2(callback) {
    console.log('funtion2');
    callback();
}

function function3() {
    console.log('function3');
}

(function () {
    var async = require('async');
    /* run funciton1 & function2 in series */
    async.series([ function1, function2], function (err, results) {
        function3();
    });

    /*  emit the serv 'connect' event every 2 seconds */
    setInterval(function () { servEvt.emit('connect'); }, 1000 * 2);
})();