Добавить анимацию slideUp в Bootstrap 4 многоуровневый выпадающий

Question

В следующем примере я также хочу анимацию слайд-слайд-слайд для внутреннего подменю Теперь анимация работает только для первого уровня.

Скрипт, который я пробовал ниже.

$('.dropdown-menu a.dropdown-toggle').on('click', function(e) {
      if (!$(this).next().hasClass('show')) {
        $(this).parents('.dropdown-menu').first().find('.show').removeClass('show');
      }
      var $subMenu = $(this).next('.dropdown-menu').stop(true, true).slideDown();
      $subMenu.toggleClass('show');


      $(this).parents('li.nav-item.dropdown.show').on('hidden.bs.dropdown', function(e) {
        $('.dropdown-submenu .show').stop(true, true).slideUp().removeClass('show');
      });
  return false;
});

Комментарий для получения дополнительной помощи. Спасибо.

$('.dropdown-menu a.dropdown-toggle').on('click', function(e) {
  if (!$(this).next().hasClass('show')) {
    $(this).parents('.dropdown-menu').first().find('.show').removeClass('show');
  }
  var $subMenu = $(this).next('.dropdown-menu');
  $subMenu.toggleClass('show');


  $(this).parents('li.nav-item.dropdown.show').on('hidden.bs.dropdown', function(e) {
    $('.dropdown-submenu .show').removeClass('show');
  });
  return false;
});

// Add slideUp animation to Bootstrap dropdown when collapsing.
$('.dropdown').on('show.bs.dropdown', function() {
  $(this).find('.dropdown-menu').first().stop(true, true).slideDown();
});
  
$('.dropdown').on('hide.bs.dropdown', function() {
  $(this).find('.dropdown-menu').first().stop(true, true).slideUp();
});

.dropdown-submenu {
    position: relative;
}

.dropdown-submenu a::after {
    transform: rotate(-90deg);
    position: absolute;
    right: 6px;
    top: .8em;
}

.dropdown-submenu .dropdown-menu {
    top: 0;
    left: 100%;
    margin-left: .1rem;
    margin-right: .1rem;
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="" crossorigin="anonymous">

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js" integrity="" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="" crossorigin="anonymous"></script>
    
<nav class="navbar navbar-expand-lg navbar-light bg-light">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarNavDropdown">
        <ul class="navbar-nav">
            <li class="nav-item active">
                <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
            </li>
            <li class="nav-item dropdown">
                <a class="nav-link dropdown-toggle" href="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown link
        </a>
                <ul class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
                    <li><a class="dropdown-item" href="#">Action</a></li>
                    <li><a class="dropdown-item" href="#">Another action</a></li>
                    <li class="dropdown-submenu">
                        <a class="dropdown-item dropdown-toggle" href="#">Submenu</a>
                        <ul class="dropdown-menu">
                            <li><a class="dropdown-item" href="#">Submenu action</a></li>
                            <li><a class="dropdown-item" href="#">Another submenu action</a></li>

                            <li class="dropdown-submenu">
                                <a class="dropdown-item dropdown-toggle" href="#">Subsubmenu</a>
                                <ul class="dropdown-menu">
                                    <li><a class="dropdown-item" href="#">Subsubmenu action</a></li>
                                    <li><a class="dropdown-item" href="#">Another subsubmenu action</a></li>
                                </ul>
                            </li>
                            <li class="dropdown-submenu">
                                <a class="dropdown-item dropdown-toggle" href="#">Second subsubmenu</a>
                                <ul class="dropdown-menu">
                                    <li><a class="dropdown-item" href="#">Subsubmenu action</a></li>
                                    <li><a class="dropdown-item" href="#">Another subsubmenu action</a></li>
                                </ul>
                            </li>

                        </ul>
                    </li>
                </ul>
            </li>
        </ul>
    </div>
</nav>