Function postMessageToWindows

src/iframe-helper.js:374–389

(iframe, targets, type, object, opt_is3P)

 * @param {boolean=} opt_is3P set to true if the iframe is 3p.
 */
export function postMessageToWindows(iframe, targets, type, object, opt_is3P) {
  if (!iframe.contentWindow) {
    return;
  }
  object['type'] = type;
  object['sentinel'] = getSentinel_(iframe, opt_is3P);
  let payload = object;
  if (opt_is3P) {
    // Serialize ourselves because that is much faster in Chrome.
    payload = 'amp-' + JSON.stringify(object);
  }
  for (let i = 0; i < targets.length; i++) {
    const target = targets[i];
    target.win./*OK*/ postMessage(payload, target.origin);
  }
}

/**
 * Gets the sentinel string.