how to send json as a response after passport authenticationin node.js

Question

I am trying this git example.

Which works well when I integrated it with my project, but what I want to achieve is to send json as a response to the client/request,

Answer 1

There is an official Custom Callback documentation:

app.get('/login', function(req, res, next) {
  passport.authenticate('local', function(err, user, info) {
    if (err) { return next(err); }
    if (!user) { return res.redirect('/login'); }
    req.logIn(user, function(err) {
      if (err) { return next(err); }
      return res.redirect('/users/' + user.username);
    });
  })(req, res, next);
});

https://github.com/passport/www.passportjs.org/blob/master/views/docs/authenticate.md