app.js

// Terminal run command: node app.js

const express = require('express');
const path = require('path');
const session = require('express-session');
const passport = require('passport');
const LocalStrategy = require('passport-local').Strategy;
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const bcrypt = require('bcryptjs')
require('dotenv').config()

const mongoDB = process.env.MONGO_URI
mongoose.connect(mongoDB, { useNewUrlParser: true });
const db = mongoose.connection;
db.on('error', console.error.bind(console, 'mongo connection error'));

const User = mongoose.model(
    'User',
    new Schema({
        username: { type: String, required: true },
        password: { type: String, required: true }
    })
);

const app = express();
app.set('views', __dirname);
app.set('view engine', 'ejs');

passport.use(
    new LocalStrategy((username, password, done) => {
        User.findOne({ username: username }, (err, user) => {
            if (err) {
                return done(err);
            }
            if (!user) {
                return done(null, false, { msg: 'Incorrect username' });
            }
            bcrypt.compare(password, user.password, (err, res) => {
                if (res) {
                  // passwords match! log user in
                  return done(null, user)
                } else {
                  // passwords do not match!
                  return done(null, false, {msg: "Incorrect password"})
                }
            })
            return done(null, user);
        });
    })
);
passport.serializeUser(function(user, done) {
    done(null, user.id);
});
passport.deserializeUser(function(id, done) {
    User.findById(id, function(err, user) {
        done(err, user);
    });
});

app.use(session({ secret: process.env.SECRET, resave: false, saveUninitialized: true }));
app.use(passport.initialize());
app.use(passport.session());
app.use(express.urlencoded({ extended: false }));

app.get("/", (req, res) => {
    res.render("index", { user: req.user });
});  
app.get('/sign-up', (req, res) => res.render('sign-up-form'));
app.post('/sign-up', (req, res, next) => {
    password: bcrypt.hash(req.body.password, 10, (err, hashedPassword) => {
        const user = new User({
            username: req.body.username,
            password: hashedPassword
        }).save(err => {
            if (err) {
                return next(err);
            }
            res.redirect('/');
        });
    })
});
app.post('/log-in', passport.authenticate('local', {
        successRedirect: '/',
        failureRedirect: '/'
    })
);
app.get("/log-out", (req, res) => {
    req.logout();
    res.redirect("/");
});

app.listen(3000, () => console.log('### App listening on port 3000 ###'));