# Pastebin kP5o2wvs
var express = require('express');
var util = require('util');


function ControllerList () {
  this.controllers = {};
  
  function add (name, controller) {
    return this.controllers[`${name}Controller`] = controller;
  }
}


var app = express();
var list = new ControllerList(); // ControllerList is a class so we create new class instance

list.add('Users', function() {
  return {
    getUserById: function(){},
    editUserById: function(){},
    deleteUserById: function(){},
    // ...
  };
});

list.add('Purchase', function () {
  return {
    getAllPurchases: function () {},
    getPurchaseById: function() {},
    editPurchaseById: function() {},
    // ...
  }
});

var router = express.Router();

router.get('/', function () { // Home Router, not Home Controller
  // Router functions are used for managing URLs (/, /settings, /about, /profile)
  list.controllers.UserController.getUserById(100).then(function (userData) {
    res.send('do something with userData');
  });
});

router.get('/purchases', function (req, res) {
  list.controllers.PurchaseController.getAllPurchases().then(function (purchases) {
    res.send('do something with all purchases');
  });
});


app.use(router);
// Start server
app.listen(8000);