LOGIN USER

 PASSPORT.AUTHENTICATE() MIDDLEWARE IS USED FOR THE AUTHENTICATION.

 passport.authenticate("local", {

    failureRedirect: "/login",

    failureFlash: true,

  })

HERE LOCAL IS LOCAL STRATEGY THAT VERIFIES USERNAME/PASSWORD AUTHENTICATION. WHEN AUTHENTICATION FAILS PAGE IS REDIRECTED TO /login

AND A FLASH MESSAGE IS SENT.

router.get("/login", (req, res) => {

  res.render("users/login.ejs");

});

router.post(

  "/login",

  passport.authenticate("local", {

    failureRedirect: "/login",

    failureFlash: true,

  }),

  async (req, res) => {

    req.flash("success", "Welcome Back!");

    res.redirect("/listings");

  }

);