Walker_Category::start_el()publicWP 2.1.0

Starts the element output.

Method of the class: Walker_Category{}

Return

null. Nothing (null).

Usage

$Walker_Category = new Walker_Category();
$Walker_Category->start_el( $output, $data_object, $depth, $args, $current_object_id );
$output(string) (required) (passed by reference — &)
Used to append additional content (passed by reference).
$data_object(WP_Term) (required)
Category data object.
$depth(int)
Depth of category in reference to parents.
$args(array)
An array of arguments. See wp_list_categories().
Default: empty array
$current_object_id(int)
ID of the current category.

Notes

Changelog

Since 2.1.0 Introduced.
Since 5.9.0 Renamed $category to $data_object and $id to $current_object_id to match parent class for PHP 8 named parameter support.

Walker_Category::start_el() code WP 6.6.2

public function start_el( &$output, $data_object, $depth = 0, $args = array(), $current_object_id = 0 ) {
	// Restores the more descriptive, specific name for use within this method.
	$category = $data_object;

	/** This filter is documented in wp-includes/category-template.php */
	$cat_name = apply_filters( 'list_cats', esc_attr( $category->name ), $category );

	// Don't generate an element if the category name is empty.
	if ( '' === $cat_name ) {
		return;
	}

	$atts         = array();
	$atts['href'] = get_term_link( $category );

	if ( $args['use_desc_for_title'] && ! empty( $category->description ) ) {
		/**
		 * Filters the category description for display.
		 *
		 * @since 1.2.0
		 *
		 * @param string  $description Category description.
		 * @param WP_Term $category    Category object.
		 */
		$atts['title'] = strip_tags( apply_filters( 'category_description', $category->description, $category ) );
	}

	/**
	 * Filters the HTML attributes applied to a category list item's anchor element.
	 *
	 * @since 5.2.0
	 *
	 * @param array   $atts {
	 *     The HTML attributes applied to the list item's `<a>` element, empty strings are ignored.
	 *
	 *     @type string $href  The href attribute.
	 *     @type string $title The title attribute.
	 * }
	 * @param WP_Term $category          Term data object.
	 * @param int     $depth             Depth of category, used for padding.
	 * @param array   $args              An array of arguments.
	 * @param int     $current_object_id ID of the current category.
	 */
	$atts = apply_filters( 'category_list_link_attributes', $atts, $category, $depth, $args, $current_object_id );

	$attributes = '';
	foreach ( $atts as $attr => $value ) {
		if ( is_scalar( $value ) && '' !== $value && false !== $value ) {
			$value       = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
			$attributes .= ' ' . $attr . '="' . $value . '"';
		}
	}

	$link = sprintf(
		'<a%s>%s</a>',
		$attributes,
		$cat_name
	);

	if ( ! empty( $args['feed_image'] ) || ! empty( $args['feed'] ) ) {
		$link .= ' ';

		if ( empty( $args['feed_image'] ) ) {
			$link .= '(';
		}

		$link .= '<a href="' . esc_url( get_term_feed_link( $category, $category->taxonomy, $args['feed_type'] ) ) . '"';

		if ( empty( $args['feed'] ) ) {
			/* translators: %s: Category name. */
			$alt = ' alt="' . sprintf( __( 'Feed for all posts filed under %s' ), $cat_name ) . '"';
		} else {
			$alt   = ' alt="' . $args['feed'] . '"';
			$name  = $args['feed'];
			$link .= empty( $args['title'] ) ? '' : $args['title'];
		}

		$link .= '>';

		if ( empty( $args['feed_image'] ) ) {
			$link .= $name;
		} else {
			$link .= "<img src='" . esc_url( $args['feed_image'] ) . "'$alt" . ' />';
		}

		$link .= '</a>';

		if ( empty( $args['feed_image'] ) ) {
			$link .= ')';
		}
	}

	if ( ! empty( $args['show_count'] ) ) {
		$link .= ' (' . number_format_i18n( $category->count ) . ')';
	}

	if ( 'list' === $args['style'] ) {
		$output     .= "\t<li";
		$css_classes = array(
			'cat-item',
			'cat-item-' . $category->term_id,
		);

		if ( ! empty( $args['current_category'] ) ) {
			// 'current_category' can be an array, so we use `get_terms()`.
			$_current_terms = get_terms(
				array(
					'taxonomy'   => $category->taxonomy,
					'include'    => $args['current_category'],
					'hide_empty' => false,
				)
			);

			foreach ( $_current_terms as $_current_term ) {
				if ( $category->term_id === $_current_term->term_id ) {
					$css_classes[] = 'current-cat';
					$link          = str_replace( '<a', '<a aria-current="page"', $link );
				} elseif ( $category->term_id === $_current_term->parent ) {
					$css_classes[] = 'current-cat-parent';
				}

				while ( $_current_term->parent ) {
					if ( $category->term_id === $_current_term->parent ) {
						$css_classes[] = 'current-cat-ancestor';
						break;
					}

					$_current_term = get_term( $_current_term->parent, $category->taxonomy );
				}
			}
		}

		/**
		 * Filters the list of CSS classes to include with each category in the list.
		 *
		 * @since 4.2.0
		 *
		 * @see wp_list_categories()
		 *
		 * @param string[] $css_classes An array of CSS classes to be applied to each list item.
		 * @param WP_Term  $category    Category data object.
		 * @param int      $depth       Depth of page, used for padding.
		 * @param array    $args        An array of wp_list_categories() arguments.
		 */
		$css_classes = implode( ' ', apply_filters( 'category_css_class', $css_classes, $category, $depth, $args ) );
		$css_classes = $css_classes ? ' class="' . esc_attr( $css_classes ) . '"' : '';

		$output .= $css_classes;
		$output .= ">$link\n";
	} elseif ( isset( $args['separator'] ) ) {
		$output .= "\t$link" . $args['separator'] . "\n";
	} else {
		$output .= "\t$link<br />\n";
	}
}