Nunjucks

You can override a .njk file’s template engine. Read more at Changing a Template’s Rendering Engine.

Nunjucks Environment Options Jump to heading #

We use Nunjucks defaults for all environment options (shown in the configure section of the Nunjucks docs).

Optional: Use your Nunjucks Environment Options Added in v1.0.0 Jump to heading #

It’s recommended to use the Configuration API to override the default Nunjucks options.

module.exports = function(eleventyConfig) {
  eleventyConfig.setNunjucksEnvironmentOptions({
    throwOnUndefined: true,
    autoescape: false, // warning: don’t do this!
  });
};

Advanced: Use your Nunjucks Environment Jump to heading #

While it is preferred and simpler to use the Options-specific API method above (new in Eleventy 1.0!)—as an escape mechanism for advanced usage you may pass in your own instance of a Nunjucks Environment using the Configuration API.

let Nunjucks = require("nunjucks");

module.exports = function(eleventyConfig) {
  let nunjucksEnvironment = new Nunjucks.Environment(
    new Nunjucks.FileSystemLoader("_includes")
  );

  eleventyConfig.setLibrary("njk", nunjucksEnvironment);
};

Supported Features Jump to heading #

Filters Jump to heading #

Filters are used to transform or modify content. You can add Nunjucks specific filters, but you probably want to add a Universal filter instead.

Read more about Nunjucks Filter syntax.

module.exports = function(eleventyConfig) {
  // Nunjucks Filter
  eleventyConfig.addNunjucksFilter("myNjkFilter", function(value) { … });

  // Nunjucks Asynchronous Filter (read on below)
  eleventyConfig.addNunjucksAsyncFilter("myAsyncNjkFilter", function(value, callback) { … });

  // Universal filters (Adds to Liquid, Nunjucks, and Handlebars)
  eleventyConfig.addFilter("myFilter", function(value) { … });
};

Usage Jump to heading #

<h1>{{ myVariable | myFilter }}</h1>

Multiple Filter Arguments Jump to heading #

module.exports = function(eleventyConfig) {
  // Nunjucks Filter
  eleventyConfig.addNunjucksFilter("concatThreeStrings", function(arg1, arg2, arg3) {
    return arg1 + arg2 + arg3;
  });
};

<h1>{{ "first" | concatThreeThings("second", "third") }}</h1>

Asynchronous Nunjucks Filters Jump to heading #

By default, almost all templating engines are synchronous. Nunjucks supports some asynchronous behavior, like filters. Here’s how that works:

module.exports = function(eleventyConfig) {
  eleventyConfig.addNunjucksAsyncFilter("myAsyncFilter", function(value, callback) {
    setTimeout(function() {
      callback(null, "My Result");
    }, 100);
  });
};

The last argument here is the callback function, the first argument of which is the error object and the second is the result data. Use this filter like you would any other: {{ myValue | myAsyncFilter }}.

Here’s a Nunjucks example with 2 arguments:

module.exports = function(eleventyConfig) {
  eleventyConfig.addNunjucksAsyncFilter("myAsyncFilter", function(value1, value2, callback) {
    setTimeout(function() {
      callback(null, "My Result");
    }, 100);
  });
};

Multi-argument filters in Nunjucks are called like this: {{ myValue1 | myAsyncFilter(myValue2) }}.

Shortcodes Jump to heading #

Shortcodes are reusable bits of content. You can add Nunjucks specific shortcodes, but it’s probably easier to add a Universal shortcode instead.

Single Shortcode Jump to heading #

module.exports = function(eleventyConfig) {
  // Nunjucks Shortcode
  eleventyConfig.addNunjucksShortcode("user", function(name, twitterUsername) { … });

  // Universal Shortcodes (Adds to Liquid, Nunjucks, JavaScript, Handlebars)
  eleventyConfig.addShortcode("user", function(name, twitterUsername) {
    return `<div class="user">
<div class="user_name">${name}</div>
<div class="user_twitter">@${twitterUsername}</div>
</div>`;
  });
};

Nunjucks Template Usage Jump to heading #

{% user "Zach Leatherman", "zachleat" %}

Outputs Jump to heading #

<div class="user">
  <div class="user_name">Zach Leatherman</div>
  <div class="user_twitter">@zachleat</div>>
</div>

Paired Shortcode Jump to heading #

module.exports = function(eleventyConfig) {
  // Nunjucks Shortcode
  eleventyConfig.addPairedNunjucksShortcode("user", function(bioContent, name, twitterUsername) { … });

  // Universal Shortcodes (Adds to Liquid, Nunjucks, Handlebars)
  eleventyConfig.addPairedShortcode("user", function(bioContent, name, twitterUsername) {
    return `<div class="user">
<div class="user_name">${name}</div>
<div class="user_twitter">@${twitterUsername}</div>
<div class="user_bio">${bioContent}</div>
</div>`;
  });
};

Nunjucks Usage Jump to heading #

Note that you can put any Nunjucks tags or content inside the {% user %} shortcode! Yes, even other shortcodes!

{% user "Zach Leatherman", "zachleat" %}
  Zach likes to take long walks on Nebraska beaches.
{% enduser %}

Outputs

<div class="user">
  <div class="user_name">Zach Leatherman</div>
  <div class="user_twitter">@zachleat</div>
  <div class="user_bio">Zach likes to take long walks on Nebraska beaches.</div>
</div>

Shortcode Named Argument Syntax (Nunjucks-only) Jump to heading #

Creates a single argument object to pass to the shortcode.

module.exports = function(eleventyConfig) {
  // Nunjucks Shortcode
  eleventyConfig.addNunjucksShortcode("user", function(user) {
    return `<div class="user">
<div class="user_name">${user.name}</div>
${user.twitter ? `<div class="user_twitter">@${user.twitter}</div>` : ''}
</div>`;
  });
};

Nunjucks Usage Jump to heading #

The order of the arguments doesn’t matter.

{% user name="Zach Leatherman", twitter="zachleat" %}
{% user twitter="zachleat", name="Zach Leatherman" %}

Outputs

<div class="user">
  <div class="user_name">Zach Leatherman</div>
  <div class="user_twitter">@zachleat</div>
</div>

Nunjucks Usage Jump to heading #

Importantly, this syntax means that any of the arguments can be optional (without having to pass in a bunch of null, null, null to maintain order).

{% user name="Zach Leatherman" %}

Outputs

<div class="user">
  <div class="user_name">Zach Leatherman</div>
</div>

Asynchronous Shortcodes Jump to heading #

Note that the configuration methods here to add asynchronous shortcodes are different than their synchronous counterparts. This is just another gentle reminder here that these API methods are pretty verbose and it’s probably easier to add a Universal shortcode instead.

module.exports = function(eleventyConfig) {
  eleventyConfig.addNunjucksAsyncShortcode("user", async function(name, twitterUsername) {
    return await fetchAThing();
  });

  eleventyConfig.addPairedNunjucksAsyncShortcode("user2", async function(content, name, twitterUsername) {
    return await fetchAThing();
  });
};

Nunjucks Usage Jump to heading #

This is identical to the synchronous Nunjucks usage.

{% user "Zach Leatherman", "zachleat" %}

{% user2 "Zach Leatherman", "zachleat" %}
  Zach likes to take long walks on Nebraska beaches.
{% enduser2 %}

Warning: The set Tag Does Not Work With Async Content Jump to heading #

Nunjucks’ {% set %} tag does not work to capture asynchronous content (e.g. asynchronous shortcodes).

Added in v1.0.0Starting in Eleventy v1.0.0, Eleventy provides a {% setAsync %} tag to work around this limitation. Notably and contrary to set, setAsync’s first argument is a string.

{% setAsync "myVariableName" %}
{% myAsyncShortcode %}
{% endsetAsync %}

<!-- Now use the variable -->
{{ myVariableName }}

Access to page data values Jump to heading #

If you aren’t using an arrow function, Nunjucks Shortcodes (and Handlebars, Liquid, and 11ty.js JavaScript Functions) will have access to Eleventy page data values without needing to pass them in as arguments.

module.exports = function(eleventyConfig) {
  eleventyConfig.addNunjucksShortcode("myShortcode", function() {
    // Available in 0.11.0 and above
    console.log( this.page );

    // For example:
    console.log( this.page.url );
    console.log( this.page.inputPath );
    console.log( this.page.fileSlug );
  });
};

Generic Global Added in v1.0.0 Jump to heading #

Nunjucks provides a custom way to add globals to templates. These can be any arbitrary JavaScript: functions, variables, etc. Note that this is not async-friendly (Nunjucks does not support await inside of templates).

module.exports = function(eleventyConfig) {
  eleventyConfig.addNunjucksGlobal("fortythree", 43);
};

{{ fortythree }}

module.exports = function(eleventyConfig) {
  eleventyConfig.addNunjucksGlobal("fortytwo", function() {
    return 42;
  });
};

{{ fortytwo() }}

Read more on the Nunjucks documentation or relevant discussion on Eleventy Issue #1060.

Other pages in Template Languages:

• HTML
• Markdown
• WebC
• JavaScript
• Nunjucks
• Liquid
• Handlebars
• Mustache
• EJS
• HAML
• Pug
• Custom

Related Docs

• Template Custom Tags
• Template Filters
• Template Shortcodes