message: Only allow post data to specific origin.
  Fixes
diff: @@ -7,6 +7,7 @@ export default function (window: Window, url: string, data: MessageData) {
  const editor = window.open(url)!;
  const wait = 10000;
  const step = 250;
  + const { origin } = new URL(url);
  // eslint-disable-next-line no-bitwise
  let count = ~~(wait / step);
  @@ -24,7 +25,7 @@ export default function (window: Window, url: string, data: MessageData) {
  if (count <= 0) {
  return;
  }
  - editor.postMessage(data, '*');
  + editor.postMessage(data, origin);
  setTimeout(send, step);
  count -= 1;
  }
  