markedForPreservation = comment => {
  if (comment.startsWith('!')) {
    return true;
  }
  if (comment.startsWith('*')) {
    // Detect jsdoc style @preserve, @copyright, @license, @cc_on (IE
    // cconditional comments)
    return /(?:^|\n)\s*\*?\s*@(?:preserve|copyright|license|cc_on)\b/.test(
      comment,
    );
  }
  return false;
}
Inspects a comment for a hint that it must be preserved by a transform.

@param {string} comment