title: why does it add "(req, res)" after the "passport.authenticate()"?
body: <p>I am following a Node.JS tutorial that I saw the following code on it:</p>
  
  <pre><code>router.get('/checkJWTtoken', cors.corsWithOptions, (req, res) =&gt; {
    passport.authenticate('jwt', {session: false}, (err, user, info) =&gt; {
      if (err)
        return next(err);
  
      if (!user) {
        res.statusCode = 401;
        res.setHeader('Content-Type', 'application/json');
        return res.json({status: 'JWT invalid!', success: false, err: info});
      }
      else {
        res.statusCode = 200;
        res.setHeader('Content-Type', 'application/json');
        return res.json({status: 'JWT valid!', success: true, user: user});
  
      }
    }) (req, res);
  });
  </code></pre>
  
  <p>I can't understand why did it add <code>(req, res)</code> after the <code>passport.authenticate()</code> in both JavaScript syntax and also specifically <code>authenticate()</code> function?</p>