We can avoid wrapping extends tags and overriding block tags, If we need to inject single block in parent template.

Step 1

Consider we have a nunjucks template with single block.

default.njk

  
  <title>Page Title</title>


  {% block content %}{% endblock %}
  

and a simple html page

index.html

---
layout: default
---
<header>
<h1>On Laughing</h1>
</header>
<main>
<p>A laugh draws a lot of painful lines.</p>
</main>
<footer>
<small>Copyright © Creator Inc.</small>
</footer>

Step 2

Now, Let's run njk.

njk index.html -b

> The current directory will be used for templates.

Result

The result will be something like

dist/index.html

  
    
    <title>Page Title</title>
  
  
    <header>
      <h1>On Laughing</h1>
    </header>
    <main>
      <p>A laugh draws a lot of painful lines.</p>
    </main>
    <footer>
      <small>Copyright © Creator Inc.</small>
    </footer>
  

Wrapping extends tag in each of our file isn't super cool,

and we can avoid this by using layout option in front-matter.

Example

Step 1

Consider we have a nunjucks template with 3 blocks.

default.njk

  
  <title>Page Title</title>


  <header>
    {% block header %}{% endblock %}
  </header>
  <main>
    {% block main %}{% endblock %}
  </main>
  <footer>
    {% block footer %}{% endblock %}
  </footer>

and a simple html page with content for these 3 blocks

index.html

---
layout: default
---
{% block header %}
<h1>On Laughing</h1>
{% endblock %}
{% block main %}
<p>A laugh draws a lot of painful lines.</p>
{% endblock %}
{% block footer %}
<small>Copyright © Creator Inc.</small>
{% endblock %}

Step 2

Now, Let's run njk.

njk index.html

> The current directory will be used for templates.

Result

The result will be something like

dist/index.html

  
    
    <title>Page Title</title>
  
  
    <header><h1>On Laughing</h1></header>
    <main><p>A laugh draws a lot of painful lines.</p></main>
    <footer><small>Copyright © Creator Inc.</small></footer>
  

We can go one step further and configure layout it in the data passed with -d or --data

Step 1

Remove front-matter from index.html

index.html

{% block header %}
<h1>On Laughing</h1>
{% endblock %}
{% block main %}
<p>A laugh draws a lot of painful lines.</p>
{% endblock %}
{% block footer %}
<small>Copyright © Creator Inc.</small>
{% endblock %}

Step 2 ( using yml )

data/page.yml

layout: default

We need to run

njk index.html -d data

Note that file name is important here, as we need page.layout property.

Step 2 ( using json )

We can pass a single json file instead of data folder

data.json

{
  "page": {
    "layout": "default"
  }
}

We need to run

njk index.html -d data.json

Result

The result will be same as our previous run (Example 2).