server.js

let http = require('http'),
  path = require('path'),
  fs = require('fs'),
  game = require('./scripts/server/game');

let mimeTypes = {
  '.js'   : 'text/javascript',
  '.html' : 'text/html',
  '.css'  : 'text/css',
  '.png'  : 'image/png',
  '.jpg'  : 'image/jpeg',
  '.wav'  : 'audio/wav',
  '.ico'  : 'image/x-icon'
};

function handleRequest(request, response) {
  let lookup = (request.url === '/') ? '/index.html' : decodeURI(request.url);
  let file = lookup.substring(1, lookup.length);

  fs.exists(file, function(exists) {
    if (exists) {
      fs.readFile(file, function(err, data) {
        if (err) {
          response.writeHead(500);
          response.end('Server Error!');
        } else {
          let headers = {'Content-type': mimeTypes[path.extname(lookup)]};
          response.writeHead(200, headers);
          response.end(data);
        }
      });
    } else {
      response.writeHead(404);
      response.end();
    }
  });
}

let server = http.createServer(handleRequest);

server.listen(3000, function() {
  game.initialize(server);
  console.log('Server is listening on port 3000');
});