the-social-notebook-server/server/server.js

'use strict';
var server;
var express = require('express');
var api = require('./api');



class Server {
  constructor() {
    console.log('Pin');
    this.app = express();
    this.app.use('/api', api);
    // this.app.get('/', (req, res) => {
    //   res.status(200)
    //     .send('Hello, world - PIN PIN PIN!');
    // });

    this.app.use((req, res, next) => {
      res.statusCode = 404;
      res.send('<h1>404 - Daaaa</h1>Not Here - Yo!');
      next();
    });
  }

  run() {
    var _server = this.app.listen(process.env.PORT || '8080', () => {
      console.log('App listening on port %s', _server.address()
        .port);
      console.log('Press Ctrl+C to quit.');
    });
  }
}

module.exports.getInstance = () => {
  if (!server) {
    server = new Server();
  }
  return server;
};