Nunjucks is a templating engine for JavaScript inspired by jinja2. It provides block inheritance, autoescaping, macros, asynchronous control, and more. Its runtime has less than 8K gzipped. It is available both in Node.js and in browsers.

Here's a snippet of Nunjucks:

{% extends "base.html" %}

{% block header %}
<h1>{{ title }}</h1>
{% endblock %}

{% block content %}
  {% for name, item in items %}
  <li>{{ name }}: {{ item }}</li>
  {% endfor %}
{% endblock %}

In Kulfon, Nunjucks templates use .njk file extension. You can also use.html if that's more convenient in your context.


Blocks are used in layout components to specify the places where the page content will be placed.

By convention there is at least one block called content which designates the main content for the final page. The markup placed within the block section in a layout component is the default value for that section.

In the following example if a page inheriting from this layout doesn't specify the content, the default h1 tag will be used instead.

{% extends "base.html" %}

{% block content %}
<h1>Default Title</h1>
{% endblock %}


Link Helper

There is the {% link %} helper available in Nunjucks templates to constract links i.e. <a href="#"> ... </a>. It automatically sets links classattribute to active for active links, which are the links that match the currently displayed pages. This is useful for building navigation bars where there is a visual clue, such as bottom border, to distinguish the currently selected navigation item.

Non-Nunjucks Pages: Org Mode & Markdown

Each page, which extends a Nunjucks layout component, must explicitly specify a block section by using {% block <name> %} ... {% endblock %} somewhere in its body.

There is, however, a convention in Kulfon that simplifies the creation of pages using either Org Mode or Markdown formats. Those pages don't need to specify the blocks explicitly. Instead, their content is stored in a content variable. This way, if you specify this variable as a default content for a main block, a corresponding layout component will be used for these pages.

Here's a layout that will display the content of each Org Mode or Markdown page with an added sidebar component.

  {% include "sidebar.njk" %}

  {% block content %}
    {{ content }}
  {% endblock %}

By default, a layout named index.njk from components/layouts/ directory will be used.

It is also possible to leverage an implicit layout inheritance which follows the directory structure in pages/. Each page located in <your-name> directory inside pages/ will first extends <your-name>.njk layout fromcomponents/layouts, and if it doesn't exist, it will default to index.njkfrom components/layouts.