nodeJS + Express-Session error: Cannot set property 'loggedin' of undefined`

Question

I am trying to create a session variable (loggedin) if the user log in, but I get TypeError: Cannot set property 'loggedin' of undefined. I can't figure out why it does not work. I have tried to reinstall session records and alsp change place for it in the code but still the same error. Any idea why I get this error?

Here is the code:

   var mysql = require('mysql');
    var express = require('express'); 
    var session = require('express-session'); 
    var bodyParser = require('body-parser'); 
    var path = require('path');
    var app = express();

    var connection = mysql.createConnection({
            host     : 'localhost',
            user     : 'root',
            password : 'password',
            database : 'database'
        });

app.use(session({secret: 'secret', resave: true, saveUninitialized: true})); //Session setup

app.use(bodyParser.urlencoded({extended : true}));
app.use(bodyParser.json());

const router6 = express.Router();

app.use('/static', express.static(path.join(__dirname + '/public'))); 

router6.get('/login', function(request, response) {
response.sendFile(path.join(__dirname + '/login.html'));
}); 


//*** SESSION VARIABLE SET BELOW ***// 
//Post for authentication, from form action

router6.post('/authThis', function(request, response) { 
   let username = request.body.username; 
   let password = request.body.password;
   console.log(username + password)

   if (username && password) { 
   connection.query('SELECT * FROM users WHERE username = ? AND password = ?', [username, password], function(error, results, fields) { 
        if (results.length > 0) { 
            request.session.loggedin = true; //Error here. Says cannot set loggedin property
            request.session.username = username; 
            response.redirect('/');
            } else {
                    response.send('Incorrect Username and/or Password!'); 
                }           
                response.end();
            });
        } else {
            response.send('Please enter Username and Password!'); //om anv & lös inte fyllts i.
            response.end();
        }
        });


//******
        module.exports = router6;

Answer 1

You're exporting the router, which should be the app.

So app has access to all middleware, router6 doesn't.

router6 is an instance of app. You ask the app instance to use session. But you actually export the router.

So module.exports = app; should fix this.