Twig recursive macro

list.html.twig

{% macro recursiveCategory(category) %}
    <li>
        <h4><a href="{{ path(category.route, category.routeParams) }}">{{ category }}</a></h4>

        {% if category.children|length %}
            <ul>
                {% for child in category.children %}
                    {{ _self.recursiveCategory(child) }}
                {% endfor %}
            </ul>
        {% endif %}
    </li>
{% endmacro %}

{% if categories %}
    <div id="categories">
        <ul>
            {% for category in categories %}
                {{ _self.recursiveCategory(category) }}
            {% endfor %}
        </ul>
    </div>
{% endif %}