eleventy-plugin-bundle

Little bundles of code, little bundles of joy.

Create minimal per-page or app-level bundles of CSS, JavaScript, or HTML to be included in your Eleventy project.

Makes it easy to implement Critical CSS, in-use-only CSS/JS bundles, SVG icon libraries, or secondary HTML content to load via XHR.

Why?

This project is a minimum-viable-bundler and asset pipeline in Eleventy. It does not perform any transpilation or code manipulation (by default). The code you put in is the code you get out (with configurable transforms if you’d like to modify the code).

For more larger, more complex use cases you may want to use a more full featured bundler like Vite, Parcel, Webpack, rollup, esbuild, or others.

But do note that a full-featured bundler has a significant build performance cost, so take care to weigh the cost of using that style of bundler against whether or not this plugin has sufficient functionality for your use case—especially as the platform matures and we see diminishing returns on code transpilation (ES modules everywhere).

Installation

No installation necessary. Starting with Eleventy v3.0.0-alpha.10 and newer, this plugin is now bundled with Eleventy.

Usage

By default, Bundle Plugin v2.0 does not include any default bundles. You must add these yourself via eleventyConfig.addBundle. One notable exception happens when using the WebC Eleventy Plugin, which adds css, js, and html bundles for you.

To create a bundle type, use eleventyConfig.addBundle in your Eleventy configuration file (default .eleventy.js):

``js
// .eleventy.js
export default function(eleventyConfig) {
eleventyConfig.addBundle("css");
};
`

This does two things:

1. Creates a new css shortcode for adding arbitrary code to this bundle
2. Adds "css" as an eligible type argument to the getBundle and getBundleFileUrl shortcodes.

$3

`js
export default function(eleventyConfig) {
eleventyConfig.addBundle("css", {
// (Optional) Folder (relative to output directory) files will write to
toFileDirectory: "bundle",

// (Optional) File extension used for bundle file output, defaults to bundle name
outputFileExtension: "css",

// (Optional) Name of shortcode for use in templates, defaults to bundle name
shortcodeName: "css",
// shortcodeName: false, // disable this feature.

// (Optional) Modify bundle content
transforms: [],

// (Optional) If two identical code blocks exist in non-default buckets, they’ll be hoisted to the first bucket in common.
hoist: true,

// (Optional) In 11ty.js templates, having a named export of bundle will populate your bundles.
bundleExportKey: "bundle",
// bundleExportKey: false, // disable this feature.
});
};
`

Read more about hoist and duplicate bundle hoisting.

$3

The following Universal Shortcodes (available in njk, liquid, hbs, 11ty.js, and webc) are provided by this plugin:

* getBundle to retrieve bundled code as a string.
* getBundleFileUrl to create a bundle file on disk and retrieve the URL to that file.

Here’s a real-world commit showing this in use on the eleventy-base-blog project.

$3

`md


My Blog Post

This is some content, I am writing markup.

{% css %}
em { font-style: italic; }
{% endcss %}

More Markdown

{% css %}
strong { font-weight: bold; }
{% endcss %}
`

Renders to:

`html


My Blog Post

This is some content, I am writing markup.

More Markdown


`

Note that the bundled code is excluded!

_There are a few more examples below!_

$3

`html




{% css %}* { color: orange; }{% endcss %}
`

$3

Writes the bundle content to a content-hashed file location in your output directory and returns the URL to the file for use like this:

`html

`

Note that writing bundles to files will likely be slower for empty-cache first time visitors but better cached in the browser for repeat-views (and across multiple pages, too).

$3

`html

{% css "defer" %}em { font-style: italic; }{% endcss %}
`

`html



`

A default bucket is implied:

`html

{% css %}em { font-style: italic; }{% endcss %}
{% css "default" %}em { font-style: italic; }{% endcss %}




`

$3

#### Critical CSS

`js
// .eleventy.js
export default function(eleventyConfig) {
eleventyConfig.addBundle("css");
};
`

Use asset bucketing to divide CSS between the default bucket and a defer bucket, loaded asynchronously.

_(Note that some HTML boilerplate has been omitted from the sample below)_

`html











{% css %}/ Inline in the head, great with @font-face! /{% endcss %}

{% css "defer" %}/ Load me later /{% endcss %}


`

Related:

* Check out the demo of Critical CSS using Eleventy Edge for a repeat view optimization without JavaScript.
* You may want to improve the above code with fetchpriority when browser support improves.

#### SVG Icon Library

Here an svg is bundle is created.

`js
// .eleventy.js
export default function(eleventyConfig) {
eleventyConfig.addBundle("svg");
};
`

`html

{% getBundle "svg" %}



{% svg %}

{% endsvg %}

And now you can use icon-close in as many SVG instances as you’d like (without repeating the heftier SVG content).





`

#### React Helmet-style additions

`js
// .eleventy.js
export default function(eleventyConfig) {
eleventyConfig.addBundle("html");
};
`

This might exist in an Eleventy layout file:

`html

{% getBundle "html", "head" %}

`

And then in your content you might want to page-specific preconnect:

`html
{% html "head" %}

{% endhtml %}
`

#### Bundle Sass with the Render Plugin

You can render template syntax inside of the {% css %} shortcode too, if you’d like to do more advanced things using Eleventy template types.

This example assumes you have added the Render plugin and the scss custom template type to your Eleventy configuration file.

`html
{% css %}
{% renderTemplate "scss" %}
h1 { .test { color: red; } }
{% endrenderTemplate %}
{% endcss %}
`

Now the compiled Sass is available in your default bundle and will show up in getBundle and getBundleFileUrl.

#### Use with WebC

Starting with @11ty/eleventy-plugin-webc@0.9.0 (track at issue #48) this plugin is used by default in the Eleventy WebC plugin. Specifically, WebC Bundler Mode) now uses the bundle plugin under the hood.

To add CSS to a bundle in WebC, you would use a

`

To add JS to a page bundle in WebC, you would use a

`

* Existing calls via WebC helpers getCss or getJs (e.g.
{% endcss %}
* a way to declare dependencies? or just defer to buckets here
* What if we want to add code duplicates? Adding alert(1); alert(1);` to alert twice?
* sourcemaps (maybe via magic-string module or https://www.npmjs.com/package/concat-with-sourcemaps)
-->