{% if name is not null %}
    {% if name is onDisk %}
        {% include 'components/icons/'~ name ~'.svg.twig' %}
    {% else %}
        <span style="color: red">Icon '{{ name }}' missing in directory '/templates/components/icons/'.</span>
    {% endif %}
{% else %}
    <span style="color: red">Icon without 'name' parameter.</span>
{% endif %}