app.js

require("dotenv").config();
const express = require("express");
const ejs = require("ejs");
const mongoose = require("mongoose");

const session = require("express-session");
const passport = require("passport");
const passportLocalMongoose = require("passport-local-mongoose");

const app = express();

app.set("view engine", "ejs");
app.use(express.urlencoded({ extended: true }));
app.use(express.static("public"));

app.use(session({
    secret: "Our little secret.",
    resave: false,
    saveUninitialized: false
}));
app.use(passport.initialize());
app.use(passport.session());

mongoose.connect("mongodb://localhost:27017/userDB", { useNewUrlParser: true, useUnifiedTopology: true });
mongoose.set("useCreateIndex",true);

const userSchema = new mongoose.Schema({
    email: String,
    password: String
});

userSchema.plugin(passportLocalMongoose);

const User = new mongoose.model("User", userSchema);//and then 2

passport.use(User.createStrategy());
passport.serializeUser(User.serializeUser());
passport.deserializeUser(User.deserializeUser());

app.get("/", function (req, res) {
    res.render("home");
});

app.get("/login", function (req, res) {
    res.render("login");
});

app.get("/register", function (req, res) {
    res.render("register");
});

app.get("/secrets",function(req,res){
    if(req.isAuthenticated()){
        res.render("secrets");
    }else{
        res.redirect("/login");
    } 
});

app.get("/logout",function(req,res){
    req.logout();
    res.redirect("/");
});

app.post("/register", function (req, res) {
    User.register({username:req.body.username},req.body.password,function(err,user){
        if(err){
            console.log(err);
            res.redirect("/register");
        }else{
            passport.authenticate("local")(req,res,function(){
                res.redirect("/secrets");
            });
        }
    });
});

app.post("/login", function (req, res) {
    const user=new User({
        username:req.body.username,
        password:req.body.password
    });
    req.login(user,function(err){
        if(err){
            console.log(err);
        }else{
            passport.authenticate("local")(req,res,function(){
                res.redirect("/secrets");
            });
        }
    });
});


app.listen(3000, function () {
    console.log("Server started on port 3000");
});