Getting role hierarchy of logged in user in Symfony 5

SecurityController.php

<?php

namespace App\Controller;
use Symfony\Component\Security\Core\Role\RoleHierarchyInterface;


class SecurityController extends AbstractController
{
 

/* ... */

    public function __construct(RoleHierarchyInterface $roleHierarchy)
    {
        $this->roleHierarchy = $roleHierarchy;
    }

    /* ... */

    /**
    * @Route("/roles", name="app_roles")
    */
    public function getRoles() {
        $user = $this->getUser();
        if (!$user) {
            return $this->json([]);
        }
        $userRoles = $user->getRoles();
        $allRoles = $this->roleHierarchy->getReachableRoleNames($userRoles);
        return $this->json($allRoles);
    }

    /* ... */
}