getExpanded example

  public function getCurrentRouteMenuTreeParameters($menu_name) {
    $active_trail = $this->menuActiveTrail->getActiveTrailIds($menu_name);

    $parameters = new MenuTreeParameters();
    $parameters->setActiveTrail($active_trail)
      // We want links in the active trail to be expanded.       ->addExpandedParents($active_trail)
      // We marked the links in the active trail to be expanded, but we also       // want their descendants that have the "expanded" flag enabled to be       // expanded.       ->addExpandedParents($this->treeStorage->getExpanded($menu_name, $active_trail));

    return $parameters;
  }

  /** * {@inheritdoc} */
  public function load($menu_name, MenuTreeParameters $parameters) {
    $data = $this->treeStorage->loadTreeData($menu_name, $parameters);
    // Pre-load all the route objects in the tree for access checks.     if ($data['route_names'] && $this->routeProvider instanceof PreloadableRouteProviderInterface) {