web/_includes/related-posts.html

<!--
 The related posts of current post.
 Placed in the bottom of every single post.
 © 2019 Cotes Chung
 Published under the MIT License
-->

{% assign MAX_SIZE = 3 %}
{% assign TAG_SCORE = 1 %}
{% assign CATEGORY_SCORE = 0.5 %}

{% assign score_list = "" | split: "" %}
{% assign post_index = 0 %}

{% for post in site.posts %}
  {% if post.url != page.url %}
    {% assign score = 0 %}

    {% for tag in post.tags %}
      {% if page.tags contains tag %}
        {% assign score = score | plus: TAG_SCORE %}
      {% endif %}
    {% endfor %}

    {% for category in post.categories %}
      {% if page.categories contains category %}
        {% assign score = score | plus: CATEGORY_SCORE %}
      {% endif %}
    {% endfor %}

    {% if score > 0 %}
      {% capture score_item %}{{ score }}:{{ post_index }}{% endcapture %}
      {% assign score_list = score_list | push: score_item %}
    {% endif %}

  {% endif %}
  {% assign post_index = post_index | plus: 1 %}
{% endfor %}

{% if score_list.size > 0 %}
  {% assign score_list = score_list | sort | reverse %}
  {% assign count = 0 %}
  <div id="related-posts" class="mt-4 mb-4 pb-3">
    <h3 class="pt-2 mt-1 mb-4" data-toc-skip>Related Posts</h3>
    <div class="card-deck mb-4">
    {% for score_item in score_list %}
      {% assign data = score_item | split: ":" %}
      {% assign index = data[1] | plus: 0 %}
      {% assign post = site.posts[index] %}
      <div class="card">
        <a href="{{ post.url }}">
          <div class="card-body">
            <span class="timeago small">
                {{ post.date | date: POST_DATE }}
                <i class="hidden">{{ post.date | date_to_xmlschema }}</i>
            </span>
            <h3 class="pt-0 mt-2 mb-3" data-toc-skip>{{ post.title }}</h3>
            <div class="text-muted small">
              <p>{{ post.content | markdownify | strip_html | truncate: 200 | replace: '&', '&amp;' }}</p>
            </div>
          </div>
        </a>
      </div>
      {% assign count = count | plus: 1 %}
      {% if count >= MAX_SIZE %}
        {% break %}
      {% endif %}
    {% endfor %}
    </div> <!-- .card-deck -->
  </div>
{% endif %}