message: return the target if the proxy is not defined
diff: @@ -66,7 +66,7 @@ export const parseDate = (date, format) => {
  export const createProxy = (target, handler) => {
  if (typeof Proxy === 'undefined') {
  - // TODO: Polyfill or simulate the behavior.
  + return target;
  }
  return new Proxy(target, handler);
  