Why doesn't Passport JS field validation work?

Question

JavaScript

Good afternoon!
Why doesn't field validation work in Passport JS?

passport.use(new LocalStrategy(
  function(username, password, done) {
    models.User.findOne({ username: username }, function (err, user) {
      if (err) { return done(err); }
      if (!user) {
        return done(null, false, { message: 'Incorrect username.' });
      }
      if (!user.validPassword(password)) {
        return done(null, false, { message: 'Incorrect password.' });
      }
      return done(null, user);
    });
  }
));

app.post('/login',
  passport.authenticate('local', { successRedirect: '/',
                                   failureRedirect: '/login',
                                   failureFlash: true
                                   })
);

Only parameters from app.post work, i.e. redirects. Flash does not work, as well as error output.