tablesort_get_sort

tablesort_get_sort($headers)

function tablesort_get_sort($headers) {
  $query = \Drupal::request()->query;
  if ($query->has('sort')) {
    return (strtolower($query->get('sort')) == 'desc') ? 'desc' : 'asc';
  }
  // The user has not specified a sort. Use the default for the currently sorted
  // header if specified; otherwise use "asc".
  else {
    // Find out which header is currently being sorted.
    $ts = tablesort_get_order($headers);
    foreach ($headers as $header) {
      if (is_array($header) && isset($header['data']) && $header['data'] == $ts['name'] && isset($header['sort'])) {
        return $header['sort'];
      }
    }
  }
  return 'asc';
}