Hoist duplicated (non-`default`) buckets (in `css` and `js`) to `default` bucket

[zachleat]

Say this island exists in two separate independent sections of a WebC page:

<is-land on:visible webc:bucket="my-bucket">
	<style webc:keep @raw="getBundle('css', 'my-bucket')"></style>

	<template data-island="once">
		<script type="module" webc:keep :src="getBundleFileUrl('js', 'my-bucket')"></script>
	</template>

	<image-compare-defined></image-compare-defined>
</is-land>

Note that this means the same bucket CSS will exist in two places on the page <style webc:keep @raw="getBundle('css', 'my-bucket')"></style>.

More simply, what should happen when we output the same non-default bundle twice?

<style webc:keep @raw="getBundle('css', 'my-bucket')"></style>
<style webc:keep @raw="getBundle('css', 'my-bucket')"></style>

Or

<style webc:keep @raw="getBundle('css', 'my-bucket')"></style>
<link rel="stylesheet" webc:keep :src="getBundleFileUrl('css', 'my-bucket')">

In those cases I’d like to hoist the CSS from the compare-defined bucket into default.

Future versions of WebC will perform this bucket hoisting more intelligently inside of WebC at a component level.

This feature is specifically for the use case when getBundle is called more than once on a single page (or getBundle is used to output the same code as getBundleFileUrl).

Notably, you exclusively use external files (getBundleFileUrl) to workaround this issue too but I think we can do better for getBundle.

[zachleat]

This behavior will be opt-in with the hoistDuplicateBundlesFor option.

Usage:

const bundlerPlugin = require("@11ty/eleventy-plugin-bundle");

module.exports = function(eleventyConfig) {
	eleventyConfig.addPlugin(bundlerPlugin, {
		hoistDuplicateBundlesFor: ["css", "js"],
	});
};

[zachleat]

Shipping with @11ty/eleventy-plugin-bundle v1.0.2