docs: function mergeNewAndOldMeta(old, updated) {
    const merged = {
      firstPublishTime: old.firstPublishTime || updated.publishTime
    };
  
    if (!Object.keys(old).length) {
      return updated;
    }
  
    if (old.history && updated.history) {
      merged.history = old.history.concat(updated.history);
    }
  
    return Object.assign(old, updated, merged);
  }