pass user

//...
router.get('/:username', auth.optional, function(req, res, next) {
  // if the profile is being navigated to by a logged in user,
  if (req.payload) {
    User.findById(req.payload.id).then(function(user) {
      if (!user) { return res.json({profile: req.profile.toProfileJSONFor(false)}); }

      return res.json({profile: req.profile.toProfileJSONFor(user)});
    });
  } else {
    return res.json({profile: req.profile.toProfileJSONFor(false)});
  }
});
//...