code: function pathParamMiddleware (req, res, next, value, name) {
      if (req.pathParams) {
        // Path parameters have already been parsed by
        req.params[name] = req.pathParams[name] || req.params[name];
      }
  
      next();
    }
docs: This is a special type of Express middleware that specifically parses path parameters and sets `req.params`.
  See http://expressjs.com/4x/api.html#router.param