system_user_presave

system_user_presave(UserInterface $account)

function system_user_presave(UserInterface $account) {
  $config = \Drupal::config('system.date');
  if ($config->get('timezone.user.configurable') && !$account->getTimeZone() && !$config->get('timezone.user.default')) {
    $account->timezone = $config->get('timezone.default');
  }
}