Jekyll (Liquid) for loop to sort posts by category in alphabetical or date-based or similiar order.

jekyll-sorted-category-for-loop-alphabetical-date.liquid

{% comment %}
#
#  Change date order by adding '| reversed'
#  To sort by title or other variables use {% assign sorted_posts = category[1] | sort: 'title' %}
#
{% endcomment %}
{% assign sorted_cats = site.categories | sort %}
{% for category in sorted_cats %}
{% assign sorted_posts = category[1] | reversed %}
<h2 id="{{category[0] | uri_escape | downcase }}">{{category[0] | capitalize}}</H2>
<ul>
  {% for post in sorted_posts %}
 	<li><a href="{{ site.url }}{{ site.baseurl }}{{  post.url }}">{{  post.title }}</a></li>
  {% endfor %}
</ul>
{% endfor %}