ToolbarItem.php

<?php

namespace Drupal\toolbar\Element;

use Drupal\Core\Render\Attribute\RenderElement;
use Drupal\Core\Render\Element\RenderElementBase;
use Drupal\Core\Url;

/**
 * Provides a toolbar item that is wrapped in markup for common styling.
 *
 * The 'tray' property contains a renderable array.
 */
class ToolbarItem extends RenderElementBase {
    
    /**
     * {@inheritdoc}
     */
    public function getInfo() {
        $class = static::class;
        return [
            '#pre_render' => [
                [
                    $class,
                    'preRenderToolbarItem',
                ],
            ],
            'tab' => [
                '#type' => 'link',
                '#title' => '',
                '#url' => Url::fromRoute('<front>'),
            ],
        ];
    }
    
    /**
     * Provides markup for associating a tray trigger with a tray element.
     *
     * A tray is a responsive container that wraps renderable content. Trays
     * present content well on small and large screens alike.
     *
     * @param array $element
     *   A renderable array.
     *
     * @return array
     *   A renderable array.
     */
    public static function preRenderToolbarItem($element) {
        $id = $element['#id'];
        // Provide attributes for a toolbar item.
        $attributes = [
            'id' => $id,
        ];
        // If tray content is present, markup the tray and its associated trigger.
        if (!empty($element['tray'])) {
            // Provide attributes necessary for trays.
            $attributes += [
                'data-toolbar-tray' => $id . '-tray',
                'role' => 'button',
                'aria-pressed' => 'false',
            ];
            // Merge in module-provided attributes.
            $element['tab'] += [
                '#attributes' => [],
            ];
            $element['tab']['#attributes'] += $attributes;
            $element['tab']['#attributes']['class'][] = 'trigger';
            // Provide attributes for the tray theme wrapper.
            $attributes = [
                'id' => $id . '-tray',
                'data-toolbar-tray' => $id . '-tray',
            ];
            // Merge in module-provided attributes.
            if (!isset($element['tray']['#wrapper_attributes'])) {
                $element['tray']['#wrapper_attributes'] = [];
            }
            $element['tray']['#wrapper_attributes'] += $attributes;
            $element['tray']['#wrapper_attributes']['class'][] = 'toolbar-tray';
        }
        $element['tab']['#attributes']['class'][] = 'toolbar-item';
        return $element;
    }

}