load-async.js

var http = require("http");
var express = require("express");
var app = express();
var server = http.createServer(app);
var startServer = function(err){
  if( err ){
    console.log("wont start server due error", err );
    throw err;
  }
  server.listen(3000,function( err ){
    if( err ){
      console.log( "error on starting server", err );
      throw err;
    }

    console.log( "server is running on port: %s", server.addres().port);
  });
};


loadDataAsync(startServer);