function wp_ajax_add_user( $action ) {
  if ( empty( $action ) ) {
    $action = 'add-user';
  }

  check_ajax_referer( $action );

  if ( ! current_user_can( 'create_users' ) ) {
    wp_die( -1 );
  }

  $user_id = edit_user();

  if ( ! $user_id ) {
    wp_die( 0 );
  } elseif ( is_wp_error( $user_id ) ) {
    $x = new WP_Ajax_Response(
      array(
        'what' => 'user',
        'id'   => $user_id,
      )
    );
    $x->send();
  }

  $user_object   = get_userdata( $user_id );
  $wp_list_table = _get_list_table( 'WP_Users_List_Table' );

  $role = current( $user_object->roles );

  $x = new WP_Ajax_Response(
    array(
      'what'         => 'user',
      'id'           => $user_id,
      'data'         => $wp_list_table->single_row( $user_object, '', $role ),
      'supplemental' => array(
        'show-link' => sprintf(
          /* translators: %s: The new user. */
          __( 'User %s added' ),
          '<a href="#user-' . $user_id . '">' . $user_object->user_login . '</a>'
        ),
        'role'      => $role,
      ),
    )
  );
  $x->send();
}