Menu tpl that shows menu level (Drupal 8)

menu--main.html.twig

{% import _self as menus %}

{#
  We call a macro which calls itself to render the full tree.
  @see http://twig.sensiolabs.org/doc/tags/macro.html
#}
{{ menus.menu_links(items, attributes, 0) }}

{% macro menu_links(items, attributes, menu_level) %}
    {% import _self as menus %}
    {% if items %}

            {% if menu_level == 0 %}
                <div class="navigation__main">
                <ul{{ attributes }}>
            {% else %}
                <ul class="navigation__submenu menu-level-{{ menu_level }}">
            {% endif %}
            {% for item in items %}
                {%
                    set classes = [
                    'menu-item',
                    item.is_expanded ? 'menu-item--expanded',
                    item.is_collapsed ? 'menu-item--collapsed',
                    item.in_active_trail ? 'menu-item--active-trail',
                ]
                %}
                <li{{ item.attributes.addClass(classes) }}>
                    {{ link(item.title, item.url) }}
                    {% if item.below %}
                        {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
                    {% endif %}
                </li>
            {% endfor %}

        {% if menu_level == 0 %}
            </ul>
            </div>
        {% else %}
            </ul>
        {% endif %}

    {% endif %}
{% endmacro %}