Walker_Nav_Menu_Checklist

16class Walker_Nav_Menu_Checklist extends Walker_Nav_Menu {17	/**18	 * @param array|false $fields Database fields to use.19	 */20	public function __construct( $fields = false ) {21		if ( $fields ) {22			$this->db_fields = $fields;23		}24	}25 26	/**27	 * Starts the list before the elements are added.28	 *29	 * @see Walker_Nav_Menu::start_lvl()30	 *31	 * @since 3.0.032	 *33	 * @param string   $output Used to append additional content (passed by reference).34	 * @param int      $depth  Depth of page. Used for padding.35	 * @param stdClass $args   Not used.36	 */37	public function start_lvl( &$output, $depth = 0, $args = null ) {38		$indent  = str_repeat( "\t", $depth );39		$output .= "\n$indent<ul class='children'>\n";40	}41 42	/**43	 * Ends the list of after the elements are added.44	 *45	 * @see Walker_Nav_Menu::end_lvl()46	 *47	 * @since 3.0.048	 *49	 * @param string   $output Used to append additional content (passed by reference).50	 * @param int      $depth  Depth of page. Used for padding.51	 * @param stdClass $args   Not used.52	 */53	public function end_lvl( &$output, $depth = 0, $args = null ) {54		$indent  = str_repeat( "\t", $depth );55		$output .= "\n$indent</ul>";56	}57 58	/**59	 * Start the element output.60	 *61	 * @see Walker_Nav_Menu::start_el()62	 *63	 * @since 3.0.064	 * @since 5.9.0 Renamed `$item` to `$data_object` and `$id` to `$current_object_id`65	 *              to match parent class for PHP 8 named parameter support.66	 *67	 * @global int        $_nav_menu_placeholder A placeholder for the nav menu item ID.68	 * @global int|string $nav_menu_selected_id  The ID of the selected nav menu.69	 *70	 * @param string   $output            Used to append additional content (passed by reference).71	 * @param WP_Post  $data_object       Menu item data object.72	 * @param int      $depth             Depth of menu item. Used for padding.73	 * @param stdClass $args              Not used.74	 * @param int      $current_object_id Optional. ID of the current menu item. Default 0.75	 */76	public function start_el( &$output, $data_object, $depth = 0, $args = null, $current_object_id = 0 ) {77		global $_nav_menu_placeholder, $nav_menu_selected_id;78 79		// Restores the more descriptive, specific name for use within this method.80		$menu_item = $data_object;81 82		$_nav_menu_placeholder = ( 0 > $_nav_menu_placeholder ) ? (int) $_nav_menu_placeholder - 1 : -1;83		$possible_object_id    = isset( $menu_item->post_type ) && 'nav_menu_item' === $menu_item->post_type ? $menu_item->object_id : $_nav_menu_placeholder;84		$possible_db_id        = ( ! empty( $menu_item->ID ) ) && ( 0 < $possible_object_id ) ? (int) $menu_item->ID : 0;85 86		$indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';87 88		$output .= $indent . '<li>';89		$output .= '<label class="menu-item-title">';90		$output .= '<input type="checkbox"' . wp_nav_menu_disabled_check( $nav_menu_selected_id, false ) . ' class="menu-item-checkbox';91 92		if ( ! empty( $menu_item->front_or_home ) ) {93			$output .= ' add-to-top';94		}95