Function getServiceForDocOrNull

src/service-helpers.js:216–224

(elementOrAmpDoc, id)

 * @return {?Object}
 */
export function getServiceForDocOrNull(elementOrAmpDoc, id) {
  const ampdoc = getAmpdoc(elementOrAmpDoc);
  const holder = getAmpdocServiceHolder(ampdoc);
  if (isServiceRegistered(holder, id)) {
    return getServiceInternal(holder, id);
  } else {
    return null;
  }
}

/**
 * Returns a promise for a service for the given id and ampdoc. Also expects