Function compareCurlsDomain

3p/recaptcha.js:218–233

* Function to compare curls domains with the passed subdomain * and window * @param {Window} win * @param {string} curlsSubdomain * @param {string} origin * @return {!Promise}

(win, curlsSubdomain, origin)

 * @return {!Promise}
 */
function compareCurlsDomain(win, curlsSubdomain, origin) {
  // Get the hostname after the culrs subdomain of the current iframe window
  const locationWithoutCurlsSubdomain = win.location.hostname
    .split('.')
    .slice(1)
    .join('.');
  const curlsHostname = curlsSubdomain + '.' + locationWithoutCurlsSubdomain;

  if (curlsHostname === win.location.hostname) {
    return Promise.resolve();
  }

  return Promise.reject(
    new Error('Origin domain does not match Iframe src: ' + origin)
  );
}