Function getOrCreateAdCid

src/ad-cid.js:32–68

(
  ampDoc,
  clientIdScope,
  opt_clientIdCookieName,
  opt_timeout
)

 * @return {!Promise<string|undefined>} A promise for a CID or undefined.
 */
export function getOrCreateAdCid(
  ampDoc,
  clientIdScope,
  opt_clientIdCookieName,
  opt_timeout
) {
  const timeout =
    isNaN(opt_timeout) || opt_timeout == null ? 1000 : opt_timeout;
  const cidPromise = Services.cidForDoc(ampDoc).then((cidService) => {
    if (!cidService) {
      return;
    }
    return cidService
      .get(
        {
          scope: dev().assertString(clientIdScope),
          createCookieIfNotPresent: true,
          cookieName: opt_clientIdCookieName,
        },
        Promise.resolve(undefined)
      )
      .catch((error) => {
        // Not getting a CID is not fatal.
        dev().error('AD-CID', error);
        return undefined;
      });
  });
  // The CID should never be crucial for an ad. If it does not come within
  // 1 second, assume it will never arrive.
  return Services.timerFor(ampDoc.win)
    .timeoutPromise(timeout, cidPromise, 'cid timeout')
    .catch((error) => {
      // Timeout is not fatal.
      dev().warn('AD-CID', error);
      return undefined;
    });
}