app.js

var createError = require("http-errors");
var express = require("express");
var path = require("path");
var cookieParser = require("cookie-parser");
var logger = require("morgan");
const expressSession = require("express-session");
var indexRouter = require("./routes/index");
var usersRouter = require("./routes/users");
const passport = require("passport");
const User = require("./routes/users");
const flash = require("connect-flash")
 
var app = express();

// view engine setup
app.set("views", path.join(__dirname, "views"));
app.set("view engine", "ejs");

// For displaying the error messsage as flash
app.use(flash()); 

// Setting sessions and passports
app.use(
  expressSession({
    resave: false,
    saveUninitialized: false,
    secret: "Prince",
  })
);
app.use(passport.initialize());
app.use(passport.session());
passport.serializeUser((User, done) => {
  done(null, User.id);
});

passport.deserializeUser((id, done) => {
  User.findById(id)
    .then(user => {
      done(null, user);
    })
    .catch(err => {
      done(err, null);
    });
});


app.use(logger("dev"));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, "public")));

app.use("/", indexRouter);
app.use("/users", usersRouter);

// catch 404 and forward to error handler
app.use(function (req, res, next) {
  next(createError(404));
});

// error handler
app.use(function (err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get("env") === "development" ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render("error");
});

module.exports = app;