title: What does `(req,res,next)` at bottom mean?
body: <pre><code>router.post('/login', isNotLoggedIn, (req, res, next) =&gt; {
      passport.authenticate('local', (authError, user, info) =&gt; {
          if (authError) {
              console.error(authError);
              return next(authError);
          }
          if (!user) {
              req.flash('loginError', info.message);
              return res.redirect('/');
          }
  
          return req.login(user, (loginError) =&gt; {
              if (loginError) {
                  console.error(loginError);
                  return next(loginError);
              }
  
              return res.redirect('/');
          });
      })(req, res, next);// &lt;-- this line
  });
  </code></pre>
  
  <p>I'm trying to learning passport package from online lecture. But, I don't get this (req,res,next) at bottom. Can anybody help me out what does it mean?</p>