gistfile1.js

function tagsMiddleware(req, res, next) {
  res.local('tags', {});
  if (req.session.logged_in) {
    User.findOne({ _id: req.session.user_id }, function (err, docs) {
      if (!err) {
        res.local('tags', {
          ignored: docs.ignored_tags,
          favorite: docs.favorite_tags
        }); 
      }   

      next();
    }); 
  } else {
    next();
  }
}