List all posts, tags and categories in Jekyll. https://github.com/zhuochun/md-writer

categories.json

---
layout: none
---
{
    "categories": [
        {% for category in site.categories %}
        "{{ category | first }}"{% unless forloop.last %},{% endunless %}
        {% endfor %}
    ]
}

posts.json

---
layout: none
---
{
    "posts": [
        {% for post in site.posts %}
        {
            "title": "{{ post.title | xml_escape }}",
            "url": "{{ site.url }}{{ post.url }}",
            "date": "{{ post.date | date_to_xmlschema }}"
        }{% unless forloop.last %},{% endunless %}
        {% endfor %}
    ]
}

tags.json

---
layout: none
---
{
    "tags": [
        {% for tag in site.tags %}
        "{{ tag | first }}"{% unless forloop.last %},{% endunless %}
        {% endfor %}
    ]
}