ContentPreprocess.php

<?php

namespace Drupal\content_moderation;

use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\node\Entity\Node;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Determines whether a route is the "Latest version" tab of a node.
 *
 * @internal
 */
class ContentPreprocess implements ContainerInjectionInterface {
    
    /**
     * The route match service.
     *
     * @var \Drupal\Core\Routing\RouteMatchInterface
     */
    protected $routeMatch;
    
    /**
     * Constructor.
     *
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   Current route match service.
     */
    public function __construct(RouteMatchInterface $route_match) {
        $this->routeMatch = $route_match;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('current_route_match'));
    }
    
    /**
     * @param array $variables
     *   Theme variables to preprocess.
     *
     * @see hook_preprocess_HOOK()
     */
    public function preprocessNode(array &$variables) {
        // Set the 'page' template variable when the node is being displayed on the
        // "Latest version" tab provided by content_moderation.
        $variables['page'] = $variables['page'] || $this->isLatestVersionPage($variables['node']);
    }
    
    /**
     * Checks whether a route is the "Latest version" tab of a node.
     *
     * @param \Drupal\node\Entity\Node $node
     *   A node.
     *
     * @return bool
     *   True if the current route is the latest version tab of the given node.
     */
    public function isLatestVersionPage(Node $node) {
        return $this->routeMatch
            ->getRouteName() == 'entity.node.latest_version' && ($pageNode = $this->routeMatch
            ->getParameter('node')) && $pageNode->id() == $node->id();
    }

}