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Walker::display_element() public WP 2.5.0

Traverse elements to create list from elements.

Display one element if the element doesn't have any children otherwise, display the element and its children. Will only traverse up to the max depth and no ignore elements under that depth. It is possible to set the max depth to include all depths, see walk() method.

This method should not be called directly, use the walk() method instead.

{} It's a method of the class: Walker{}

No Hooks.

Return

null. Nothing.

Usage

$Walker = new Walker();
$Walker->display_element( $element, $children_elements, $max_depth, $depth, $args, $output );
$element(object) (required)
Data object.
$children_elements(array) (required) (passed by reference — &)
List of elements to continue traversing (passed by reference).
$max_depth(int) (required)
Max depth to traverse.
$depth(int) (required)
Depth of current element.
$args(array) (required)
An array of arguments.
$output(string) (required) (passed by reference — &)
Used to append additional content (passed by reference).

Changelog

Since 2.5.0 Introduced.

Code of Walker::display_element() WP 5.7.2

<?php
public function display_element( $element, &$children_elements, $max_depth, $depth, $args, &$output ) {
	if ( ! $element ) {
		return;
	}

	$id_field = $this->db_fields['id'];
	$id       = $element->$id_field;

	// Display this element.
	$this->has_children = ! empty( $children_elements[ $id ] );
	if ( isset( $args[0] ) && is_array( $args[0] ) ) {
		$args[0]['has_children'] = $this->has_children; // Back-compat.
	}

	$this->start_el( $output, $element, $depth, ...array_values( $args ) );

	// Descend only when the depth is right and there are children for this element.
	if ( ( 0 == $max_depth || $max_depth > $depth + 1 ) && isset( $children_elements[ $id ] ) ) {

		foreach ( $children_elements[ $id ] as $child ) {

			if ( ! isset( $newlevel ) ) {
				$newlevel = true;
				// Start the child delimiter.
				$this->start_lvl( $output, $depth, ...array_values( $args ) );
			}
			$this->display_element( $child, $children_elements, $max_depth, $depth + 1, $args, $output );
		}
		unset( $children_elements[ $id ] );
	}

	if ( isset( $newlevel ) && $newlevel ) {
		// End the child delimiter.
		$this->end_lvl( $output, $depth, ...array_values( $args ) );
	}

	// End this element.
	$this->end_el( $output, $element, $depth, ...array_values( $args ) );
}