Walker_Category_Checklist

19class Walker_Category_Checklist extends Walker {20	public $tree_type = 'category';21	public $db_fields = array(22		'parent' => 'parent',23		'id'     => 'term_id',24	); // TODO: Decouple this.25 26	/**27	 * Starts the list before the elements are added.28	 *29	 * @see Walker::start_lvl()30	 *31	 * @since 2.5.132	 *33	 * @param string $output Used to append additional content (passed by reference).34	 * @param int    $depth  Depth of category. Used for tab indentation.35	 * @param array  $args   An array of arguments. See {@see wp_terms_checklist()}.36	 */37	public function start_lvl( &$output, $depth = 0, $args = array() ) {38		$indent  = str_repeat( "\t", $depth );39		$output .= "$indent<ul class='children'>\n";40	}41 42	/**43	 * Ends the list of after the elements are added.44	 *45	 * @see Walker::end_lvl()46	 *47	 * @since 2.5.148	 *49	 * @param string $output Used to append additional content (passed by reference).50	 * @param int    $depth  Depth of category. Used for tab indentation.51	 * @param array  $args   An array of arguments. See {@see wp_terms_checklist()}.52	 */53	public function end_lvl( &$output, $depth = 0, $args = array() ) {54		$indent  = str_repeat( "\t", $depth );55		$output .= "$indent</ul>\n";56	}57 58	/**59	 * Start the element output.60	 *61	 * @see Walker::start_el()62	 *63	 * @since 2.5.164	 * @since 5.9.0 Renamed `$category` to `$data_object` and `$id` to `$current_object_id`65	 *              to match parent class for PHP 8 named parameter support.66	 *67	 * @param string  $output            Used to append additional content (passed by reference).68	 * @param WP_Term $data_object       The current term object.69	 * @param int     $depth             Depth of the term in reference to parents. Default 0.70	 * @param array   $args              An array of arguments. See {@see wp_terms_checklist()}.71	 * @param int     $current_object_id Optional. ID of the current term. Default 0.72	 */73	public function start_el( &$output, $data_object, $depth = 0, $args = array(), $current_object_id = 0 ) {74		// Restores the more descriptive, specific name for use within this method.75		$category = $data_object;76 77		if ( empty( $args['taxonomy'] ) ) {78			$taxonomy = 'category';79		} else {80			$taxonomy = $args['taxonomy'];81		}82 83		if ( 'category' === $taxonomy ) {84			$name = 'post_category';85		} else {86			$name = 'tax_input[' . $taxonomy . ']';87		}88 89		$args['popular_cats'] = ! empty( $args['popular_cats'] ) ? array_map( 'intval', $args['popular_cats'] ) : array();90 91		$class = in_array( $category->term_id, $args['popular_cats'], true ) ? ' class="popular-category"' : '';92 93		$args['selected_cats'] = ! empty( $args['selected_cats'] ) ? array_map( 'intval', $args['selected_cats'] ) : array();94 95		if ( ! empty( $args['list_only'] ) ) {96			$aria_checked = 'false';97			$inner_class  = 'category';98