block_core_accordion_item_render( array $attributes, string $content )

13function block_core_accordion_item_render( array $attributes, string $content ): string {14	if ( '' === $content ) {15		return $content;16	}17 18	$p         = new WP_HTML_Tag_Processor( $content );19	$unique_id = wp_unique_id( 'accordion-item-' );20 21	// Initialize the state of the item on the server using a closure,22	// since we need to get derived state based on the current context.23	wp_interactivity_state(24		'core/accordion',25		array(26			'isOpen' => function () {27				$context = wp_interactivity_get_context();28				return $context['openByDefault'];29			},30		)31	);32 33	if ( $p->next_tag( array( 'class_name' => 'wp-block-accordion-item' ) ) ) {34		$open_by_default = $attributes['openByDefault'] ? 'true' : 'false';35		$p->set_attribute( 'data-wp-context', '{ "id": "' . $unique_id . '", "openByDefault": ' . $open_by_default . ' }' );36		$p->set_attribute( 'data-wp-class--is-open', 'state.isOpen' );37		$p->set_attribute( 'data-wp-init', 'callbacks.initAccordionItems' );38		$p->set_attribute( 'data-wp-on-window--hashchange', 'callbacks.hashChange' );39 40		if ( $p->next_tag( array( 'class_name' => 'wp-block-accordion-heading__toggle' ) ) ) {41			$p->set_attribute( 'data-wp-on--click', 'actions.toggle' );42			$p->set_attribute( 'id', $unique_id );43			$p->set_attribute( 'aria-controls', $unique_id . '-panel' );44			$p->set_attribute( 'data-wp-bind--aria-expanded', 'state.isOpen' );45 46			if ( $p->next_tag( array( 'class_name' => 'wp-block-accordion-panel' ) ) ) {47				$p->set_attribute( 'id', $unique_id . '-panel' );48				$p->set_attribute( 'aria-labelledby', $unique_id );49				$p->set_attribute( 'data-wp-bind--hidden', 'state.isHidden' );50				$p->set_attribute( 'data-wp-on--beforematch', 'actions.handleBeforeMatch' );51 52				// Only modify content if all directives have been set.53				$content = $p->get_updated_html();54			}55		}56	}57 58	/*59	 * If an Accordion Item is collapsed by default, ensure any contained IMG has fetchpriority=low to deprioritize it60	 * from contending with resources in the critical rendering path. In contrast, remove the loading attribute to61	 * prevent the image from not being available when the item is expanded.62	 */63	if ( ! $attributes['openByDefault'] ) {64		$processor = new WP_HTML_Tag_Processor( $content );65		while ( $processor->next_tag( 'IMG' ) ) {66			$processor->set_attribute( 'fetchpriority', 'low' );67		}68		$content = $processor->get_updated_html();69	}70 71	return $content;72}