If I want to handle errors from "incorrect" logins on this route how to collect (err) and where?
// POST LOGIN
usersRouter
.route('/login')
.post(passport.authenticate('local'), (req, res, next) => {
// for example, to declare an if here to catch err and call next with err...
res.statusCode = 200;
res.setHeader('Content-Type', 'application/json');
res.json({ success: true, status: 'You are successfully logged in!' });
});