docs/_includes/code/start.html

{% if include.type == 'promise' %}
  {% assign class = 'active' %}
{% else %}
  {% assign class = '' %}
{% endif %}
<div
  class="tab-pane {{ class }}"
  id="{{ include.type }}"
  data-code-id="{{ include.id }}"
  data-code-type="{{ include.type }}"
>