.eleventy.js

import { DateTime } from "luxon";
import CleanCSS from "clean-css";
import UglifyJS from "uglify-js";
import htmlmin from "html-minifier";
import markdownIt from "markdown-it";
import markdownItAttrs from "markdown-it-attrs";
import markdownItAnchor from "markdown-it-anchor";
import eleventyNavigationPlugin from "@11ty/eleventy-navigation";
import { eleventyImageTransformPlugin } from "@11ty/eleventy-img";
import fontAwesomePlugin from "@11ty/font-awesome";
import bundlePlugin from "@11ty/eleventy-plugin-bundle";
// import addPairedShortcode from "";

export default function(eleventyConfig) {

  // Eleventy Image Plugin https://www.11ty.dev/docs/plugins/image/
  eleventyConfig.addPlugin(eleventyImageTransformPlugin)

  // Eleventy Navigation https://www.11ty.dev/docs/plugins/navigation/
  eleventyConfig.addPlugin(eleventyNavigationPlugin);

  // Add Bundle Plugin
  eleventyConfig.addPlugin(bundlePlugin);

  // Font Awesome Plugin
  eleventyConfig.addPlugin(fontAwesomePlugin);

  // Merge data instead of overriding
  // https://www.11ty.dev/docs/data-deep-merge/
  eleventyConfig.setDataDeepMerge(true);

  // Blog posts collection
  eleventyConfig.addCollection("post", collection => {
    return collection.getFilteredByGlob("posts/*.md").reverse();
  });

  // Add support for maintenance-free post authors
  eleventyConfig.addCollection("authors", collection => {
    const blogs = collection.getFilteredByGlob("posts/*.md");
    return blogs.reduce((coll, post) => {
      const author = post.data.author;
      if (!author) {
        return coll;
      }
      if (!coll.hasOwnProperty(author)) {
        coll[author] = [];
      }
      coll[author].push(post.data);
      return coll;
    }, {});
  });

  // Date formatting (human readable)
  eleventyConfig.addFilter("readableDate", dateObj => {
    return DateTime.fromJSDate(dateObj).toFormat("dd LLL yyyy");
  });

  // Date formatting (machine readable)
  eleventyConfig.addFilter("machineDate", dateObj => {
    return DateTime.fromJSDate(dateObj).toFormat("yyyy-MM-dd");
  });

  // Date for Current Year
  eleventyConfig.addFilter("currentYear", () => {
    return new Date().getFullYear();
  });

  // Extract headings for table of contents
  eleventyConfig.addFilter("extractHeadings", function(content) {
    const headingRegex = /<h([2-4])[^>]*id="([^"]*)"[^>]*>(.*?)<\/h\1>/g;
    const headings = [];
    let match;
    
    while ((match = headingRegex.exec(content)) !== null) {
      headings.push({
        level: parseInt(match[1]),
        id: match[2],
        text: match[3].replace(/<[^>]*>/g, '').replace(/&amp;/g, '&')
      });
    }
    
    return headings;
  });

  // Minify CSS
  eleventyConfig.addFilter("cssmin", function(code) {
    return new CleanCSS({}).minify(code).styles;
  });

  // Minify JS
  eleventyConfig.addFilter("jsmin", function(code) {
    let minified = UglifyJS.minify(code);
    if (minified.error) {
      console.log("UglifyJS error: ", minified.error);
      return code;
    }
    return minified.code;
  });

  // Minify HTML output
  eleventyConfig.addTransform("htmlmin", function(content, outputPath) {
    if (outputPath.indexOf(".html") > -1) {
      let minified = htmlmin.minify(content, {
        useShortDoctype: true,
        removeComments: true,
        collapseWhitespace: true
      });
      return minified;
    }
    return content;
  });

  // Don't process folders with static assets e.g. images
  eleventyConfig.addPassthroughCopy("favicon.ico");
  eleventyConfig.addPassthroughCopy("static/img");
  eleventyConfig.addPassthroughCopy("admin");
  eleventyConfig.addPassthroughCopy("_includes/assets/css/inline.css");
  eleventyConfig.addPassthroughCopy("static/js");

  /* Markdown Plugins */
  let options = {
    html: true,
    breaks: true,
    linkify: true
  };

  let opts = {
    permalink: false,
    level: [2, 3, 4] // Generate anchors for h2, h3, h4
  };

  eleventyConfig.setLibrary("md", markdownIt(options)
    .use(markdownItAnchor, opts)
    .use(markdownItAttrs)
  );

  return {
    templateFormats: ["md", "njk", "html", "liquid"],
    pathPrefix: "/",
    markdownTemplateEngine: "liquid",
    htmlTemplateEngine: "njk",
    dataTemplateEngine: "njk",
    dir: {
      input: ".",
      includes: "_includes",
      data: "_data",
      output: "_site"
    }
  };
};