I am getting Error: req#logout requires a callback function when trying to call /logout.
I expect to logout and then when I try to authenticate again, to see the actual Google OAuth2.0 screen and not just “You are authenticated”.
I assume this happens because of the fact I have a session alive, hence I added req.logOut and req.session.destroy to get rid of it, but if I uncomment req.logOut I keep getting the error.
I tried to redefine /logout as in the code but I am still getting the same error.

index.js

const PORT = 3000;

require("dotenv").config();
const express = require("express");
const app = express();
const mongoose = require("mongoose");
const passport = require("passport");
const { isLoggedIn } = require("./middlewares/authMiddleware");
const session = require("express-session");
const bodyParser = require("body-parser");

// parse application/json
app.use(bodyParser.json());

// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }));

app.use(express.json());

app.use(
  session({
    secret: process.env.SESSION_SECRET,
    resave: false, // don't save session if unmodified
    saveUninitialized: false, // don't create session until something stored
  })
);

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

// Import routes
const userRoute = require("./app/routes/UserController");

// Route middleware
app.use("/api/v1/users", userRoute);

app.get("/", (req, res) => {
  res.send('<a href="/auth/google">Authenticate with Google</a>');
});

app.get(
  "/auth/google/callback",
  passport.authenticate("google", {
    successRedirect: "/protected",
    failureRedirect: "/auth/failure",
  })
);

app.get("/auth/failure", (req, res) => {
  res.send("Failed to authenticate..");
});

app.get(
  "/auth/google",
  passport.authenticate("google", { scope: ["email", "profile"] })
);

app.get("/protected", isLoggedIn, (req, res) => {
  res.send("You are authenticated");
});

app.get("/logout", (req, res, next) => {
  if (req.session) {
    req.logOut();
    req.session.destroy();
    res.redirect("/");
  }
});

/**
 * Configure mongoose
 */
// mongoose.Promise = global.Promise;
app.locals.db = mongoose
  .connect(process.env.DB_CONNECT, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
  })
  .then(() => {
    console.log("Connected to Database");

    app.listen(PORT, () => {
      console.log(`Server listening on port ${PORT}`);
    });
  });

authMiddleware.js

const passport = require("passport");
const GoogleStrategy = require("passport-google-oauth20").Strategy;
const User = require("../app/models/User");

passport.serializeUser((user, done) => {
  done(null, user);
});

passport.deserializeUser(function (user, done) {
  done(null, user);
});

passport.use(
  new GoogleStrategy(
    {
      clientID: process.env.GOOGLE_CLIENT_ID,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET,
      callbackURL: process.env.GOOGLE_CALLBACK_URL,
    },
    function (accessToken, refreshToken, profile, done) {
      User.findOne({ "oauth.googleId": profile.id })
        .then((existingUser) => {
          if (existingUser) {
            return done(null, existingUser);
          } else {
            var newUser = new User({
              name: profile.givenName,
              surname: profile.familyName,
              email: profile.emails[0].value,
              username: profile.displayName,
              oauth: {
                googleId: profile.id,
                displayName: profile.displayName,
                firstName: profile.name.givenName,
                lastName: profile.name.familyName,
                email: profile.emails[0].value,
              },
            });
            newUser
              .save()
              .then((newUser) => {
                return done(null, newUser);
              })
              .catch((err) => {
                return done(err);
              });
          }
        })
        .catch((err) => {
          return done(err);
        });
    }
  )
);

module.exports.isLoggedIn = function (req, res, next) {
  req.user ? next() : res.sendStatus(401);
};

module.exports.passport = passport;