liquid-intersection

intersection.liquid

{% comment %}Input from article{% endcomment %}
{% assign articleTopics = "t3,t4,t5" | split: "," %}
{% assign articleAuthors = "a1,a2" | split: "," %}

{% comment %}This will come from user.topics, user.authors{% endcomment %}
{% assign userTopics = "t1,t3,t5" | split: "," %}
{% assign userAuthors = "a2,a4" | split: "," %}

{% for userTopic in userTopics %}
  {% if articleTopics contains userTopic %}
		{% assign topicsIntersection = topicsIntersection | concat: userTopic  %}
  {% endif %}
{% endfor %}

{% if topicsIntersection.size > 0 %}
	Push-Thema: {{topicsIntersection.first }}
{% else %}
  {% for userAuthor in userAuthors %}
	  {% if articleAuthors contains userAuthor %}
			{% assign authorsIntersection = authorsIntersection | concat: userAuthor %}
  	{% endif %}
	{% endfor %}
	Push-Autor: {{authorsIntersection.first}}
{% endif %}