code: function dbError(tx, err) {
              if (calledDBError) {
                  return;
              }
              err = idbModules.util.findError(arguments);
              req.readyState = "done";
              req.error = err || "DOMError";
              var e = idbModules.util.createEvent("error");
              e.debug = arguments;
              idbModules.util.callback("onerror", req, e);
              calledDBError = true;
          }
docs: cast to a string