Advanced Node and Express - Registration of New Users

server.js

'use strict';
require('dotenv').config();
const express = require('express');
const myDB = require('./connection');
const fccTesting = require('./freeCodeCamp/fcctesting.js');
const session = require('express-session');
const passport = require('passport');
const ObjectID = require('mongodb').ObjectID;
const LocalStrategy = require('passport-local');

const app = express();
app.set('view engine', 'pug');

fccTesting(app); // For fCC testing purposes
app.use('/public', express.static(process.cwd() + '/public'));
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

app.use(session({
  secret: process.env.SESSION_SECRET,
  resave: true,
  saveUninitialized: true,
  cookie: { secure: false }
}));

app.use(passport.initialize());
app.use(passport.session());

myDB(async (client) => {
  const myDataBase = await client.db('database').collection('users');

  // Be sure to change the title
  app.route('/').get((req, res) => {
    // Change the response to render the Pug template
    res.render('pug', { title: 'Connected to Database', message: 'Please login', showLogin: true, showRegistration: true });
  });
  app.route('/login').post(passport.authenticate('local', { failureRedirect: '/' }), (req, res) => {
    res.redirect('/profile');
  });
  app.route('/profile').get(ensureAuthenticated, (req, res) => {
    res.render(process.cwd() + '/views/pug/profile', { username: req.user.username });
  });
  app.route('/logout').get((req, res) => {
    req.logout();
    res.redirect('/');
  });

  app.route('/register').post(
    (req, res, next) => {
      myDataBase.findOne({ username: req.body.username }, function (err, user) {
        if (err) {
          next(err);
        } else if (user) {
          res.redirect('/');
        } else {
          myDataBase.insertOne({ username: req.body.username, password: req.body.password }, (err, doc) => {
            if (err) {
              res.redirect('/');
            } else {
              next(null, doc.ops[0]);
            }
          });
        }
      });
    },
    passport.authenticate('local', { failureRedirect: '/' }),
    (req, res, next) => {
      res.redirect('/profile');
    }
  );
  app.use((req, res, next) => {
    res.status(404).type('text').send('Not Found');
  });
  passport.serializeUser((user, done) => {
    done(null, user._id);
  });
  passport.deserializeUser((id, done) => {
    myDataBase.findOne({ _id: new ObjectID(id) }, (err, doc) => {
      if (err) return console.error(err);
      done(null, doc);
    });
  });
  passport.use(new LocalStrategy(
    function (username, password, done) {
      myDataBase.findOne({ username: username }, function (err, user) {
        if (err) { return done(err); }
        if (!user) { return done(null, false); }
        if (password !== user.password) { return done(null, false); }
        return done(null, user);
      });
    }
  ));
}).catch((e) => {
  app.route('/').get((req, res) => {
    res.render('pug', { title: e, message: 'Unable to login' });
  });
});

function ensureAuthenticated(req, res, next) {
  if (req.isAuthenticated()) {
    return next();
  }
  res.redirect('/');
}

app.listen(process.env.PORT || 3000, () => {
  console.log('Listening on port ' + process.env.PORT);
});