Jekyll has first class support for tags and categories in blog posts.
Tag feature basically consists of three abilities:
- a) adding tags to posts,
- b) displaying all tags, with posts count and
- c) browsing posts by tag.
Adding tags to posts
Tags for a post are defined in the post’s front matter using either the key tag for a single entry or tags for multiple entries.
Since Jekyll expects multiple items mapped to the key tags,
it will automatically split a string entry if it contains whitespace.
For example, while front matter tag: classic hollywood will be processed into a singular entity "classic hollywood",
front matter tags: classic hollywood will be processed into an array of entries ["classic", "hollywood"].
Irrespective of the front matter key chosen(tag or tags),
Jekyll stores the metadata mapped to the plural key which is exposed to Liquid templates.
Displaying Tags
displaying tags on a post
{% if page.tags.size > 0 %}
{% for tagName in page.tags %}
- {{ tagName }}
{% endfor %}
{% endif %}displaying all tags in a site
Jekyll offers global array site.tags which contains information on all the tags.
Each element is an array as follows: [0] - tag name and [1] - all posts for the tag.
{% if site.tags.size > 0 %}
<ul>
{% for tag in site.tags %}
{% assign tagName = tag | first | downcase %}
{% assign postsCount = tag | last | size %}
<li><a href="/tags?tagName={{ tagName }}">{{ tagName }}</a>({{ postsCount }})</li>
{% endfor %}
</ul>
{% endif %}示例如下：
- java(1)
- agent(1)
- instrumentation(1)
All tags registered in the current site are exposed to Liquid templates via site.tags.
Iterating over site.tags on a page will yield another array with two items,
where the first item is the name of the tag and the second item being an array of posts with that tag.
{% for tag in site.tags %}
<p>{{ tag[0] }}</p>
<ul>
{% for post in tag[1] %}
<li><a href="{{ post.url }}">{{ post.title }}</a></li>
{% endfor %}
</ul>
{% endfor %}示例如下：