Function parseIfNeeded

src/iframe-helper.js:409–428

(data)

 * @visibleForTesting
 */
export function parseIfNeeded(data) {
  if (typeof data == 'string') {
    if (data.charAt(0) == '{') {
      data =
        tryParseJson(data, (e) => {
          dev().warn(
            'IFRAME-HELPER',
            'Postmessage could not be parsed. ' +
              'Is it in a valid JSON format?',
            e
          );
        }) || null;
    } else if (isAmpMessage(data)) {
      data = deserializeMessage(data);
    } else {
      data = null;
    }
  }
  return /** @type {?JsonObject} */ (data);
}

/**
 * Manages a postMessage API for an iframe with a subscription message and