How is return res.json() different from res.json()?

Question

JavaScript

How is return res.json() different from res.json()?
And how is return next() different from next()?
In both cases, everything works the same way.

app.post('/login', function(req, res, next) {
  passport.authenticate('local', function(err, user, info) {
    if (err) return next(err);
    if (!user) {
      return res.status(401).json({ status: 'error', code: 'unauthorized' });
    } else {
      return res.json({ token: jwt.sign({id: user.id}, secret) });
    }
  })(req, res, next);
});

Answer 1

return is just the end of the function.
and

res.json({ token: jwt.sign({id: user.id}, secret) });
return;

This is the same.

Answer 2

Well, let's see where we return. In passport.authenticate, right? And then what? - callback. And the result of the callback is processed? - No. Well, here's the answer - you return to the void.