Why the else part of the '/logout' is not working even if i tried '/logout' many times?

I am being able to logout successfully, but the else part of the code does not come into play even when I browse /logout successfully.

router.get('/logout',(req,res)=>{
    if(req.session){
      req.session.destroy();
      res.clearCookie('session-id');
      res.redirect('/');
    }
    else{
      var err = new Error('You are not logged in!');
      err.status = 403;
      next(err);
    }
  });

Expectation: After logging out, the next time when a user requests /logout they should receive the reply specified in the else part, i.e. "You are not logged in!"