initialize-proxy.js

/**
 * Encapsulate the operation of creating a Proxy object assuring compatibility
 * across different versions of Node.js and browsers.
 */
initializeProxy(handler: ProxyHandler, proto: Object): Proxy {
  let proxy;
  if (typeof Proxy.create !== 'undefined') {
    proxy = Proxy.create(handler, proto);
  } else {
    proxy = new Proxy(proto, handler);
  }

  return proxy;
}