.eleventy.js

const {EleventyServerlessBundlerPlugin} = require('@11ty/eleventy');
const serialize = require('serialize-javascript');
const {titleCase} = require('title-case');
const {isWebUri} = require('valid-url');
const markdownIt = require('markdown-it');
const markdownItFootnote = require('markdown-it-footnote');

/**
 * @typedef {import('@11ty/eleventy/src/UserConfig')} EleventyConfig
 * @typedef {ReturnType<import('@11ty/eleventy/src/defaultConfig')>} EleventyReturnValue
 *
 * @type {(eleventyConfig: EleventyConfig)) => EleventyReturnValue}
 */
module.exports = function (eleventyConfig) {
	let markdownItOptions = {
		html: true,
		breaks: true,
		linkify: true,
	};
	let markdownLib = markdownIt(markdownItOptions).use(markdownItFootnote);
	eleventyConfig.setLibrary('md', markdownLib);

	eleventyConfig.addPlugin(EleventyServerlessBundlerPlugin, {
		name: 'serverless',
		functionsDir: './netlify/functions',
		inputDir: './src',
		copy: ['src/themes/'],
	});

	eleventyConfig.addPassthroughCopy('src/assets');
	eleventyConfig.addPassthroughCopy('src/scripts');
	eleventyConfig.addPassthroughCopy('src/themes');

	eleventyConfig.addFilter('debug', (output) =>
		JSON.stringify(output, null, 2)
	);
	eleventyConfig.addFilter('formatThemeName', (input) =>
		titleCase(input.replace(/\-/g, ' '))
	);
	eleventyConfig.addFilter('serialize', (input) =>
		serialize(input, {isJSON: true})
	);
	eleventyConfig.addFilter('toStylesheet', toStylesheet);

	return {
		dir: {
			input: 'src',
		},
	};
};

/**
 * Takes chosen theme and determines stylesheet href
 * @param {string} theme chosen theme
 * @param {{
 * 		list: string[],
 * 		normalized: Object<string, true>
 * }}
 * @returns {string} valid href for chosen theme
 */
function toStylesheet(theme = 'default', themes) {
	if (isWebUri(theme)) {
		return theme;
	} else if (themes.normalized[theme]) {
		return `/themes/${theme}.css`;
	} else {
		return `/themes/default.css`;
	}
}