lib/index.js
function custom (fn) {
  return function (req, res, next) {
    fn(req, function (result) {
      if (result === true) { return next(); }
      next(new ErrorUnauthorized('Authentication Failed'));
    });
  };
}
function custom (fn) {
  return function (req, res, next) {
    fn(req, function (result) {
      if (result === true) { return next(); }
      next(new ErrorUnauthorized('Authentication Failed'));
    });
  };
}
fn returns true/false to callback