Walker_Category

17class Walker_Category extends Walker {18 19	/**20	 * What the class handles.21	 *22	 * @since 2.1.023	 * @var string24	 *25	 * @see Walker::$tree_type26	 */27	public $tree_type = 'category';28 29	/**30	 * Database fields to use.31	 *32	 * @since 2.1.033	 * @var string[]34	 *35	 * @see Walker::$db_fields36	 * @todo Decouple this37	 */38	public $db_fields = array(39		'parent' => 'parent',40		'id'     => 'term_id',41	);42 43	/**44	 * Starts the list before the elements are added.45	 *46	 * @since 2.1.047	 *48	 * @see Walker::start_lvl()49	 *50	 * @param string $output Used to append additional content. Passed by reference.51	 * @param int    $depth  Optional. Depth of category. Used for tab indentation. Default 0.52	 * @param array  $args   Optional. An array of arguments. Will only append content if style argument53	 *                       value is 'list'. See wp_list_categories(). Default empty array.54	 */55	public function start_lvl( &$output, $depth = 0, $args = array() ) {56		if ( 'list' !== $args['style'] ) {57			return;58		}59 60		$indent  = str_repeat( "\t", $depth );61		$output .= "$indent<ul class='children'>\n";62	}63 64	/**65	 * Ends the list of after the elements are added.66	 *67	 * @since 2.1.068	 *69	 * @see Walker::end_lvl()70	 *71	 * @param string $output Used to append additional content. Passed by reference.72	 * @param int    $depth  Optional. Depth of category. Used for tab indentation. Default 0.73	 * @param array  $args   Optional. An array of arguments. Will only append content if style argument74	 *                       value is 'list'. See wp_list_categories(). Default empty array.75	 */76	public function end_lvl( &$output, $depth = 0, $args = array() ) {77		if ( 'list' !== $args['style'] ) {78			return;79		}80 81		$indent  = str_repeat( "\t", $depth );82		$output .= "$indent</ul>\n";83	}84 85	/**86	 * Starts the element output.87	 *88	 * @since 2.1.089	 * @since 5.9.0 Renamed `$category` to `$data_object` and `$id` to `$current_object_id`90	 *              to match parent class for PHP 8 named parameter support.91	 *92	 * @see Walker::start_el()93	 *94	 * @param string  $output            Used to append additional content (passed by reference).95	 * @param WP_Term $data_object       Category data object.96	 * @param int     $depth             Optional. Depth of category in reference to parents. Default 0.