.eleventy.js

const { DateTime } = require("luxon");
const CleanCSS = require("clean-css");
const UglifyJS = require("uglify-es");
const htmlmin = require("html-minifier");
const slugify = require("slugify");
const eleventyPluginNavigation = require("@11ty/eleventy-navigation");
const eleventyPluginHelmet = require('eleventy-plugin-helmet');
const eleventyPluginPWA = require("eleventy-plugin-pwa");

module.exports = (eleventyConfig) => {

  //
  // Plugins
  //

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

  // Eleventy Helmet Plugin
  // https://github.com/vseventer/eleventy-plugin-helmet
  eleventyConfig.addPlugin(eleventyPluginHelmet);

  // Eleventy PWA Plugin
  // https://github.com/okitavera/eleventy-plugin-pwa
  eleventyConfig.addPlugin(eleventyPluginPWA, {
    swDest: "dist/sw.js"
  });

  //
  // Filters
  //

  // Date format (human readable)
  //
  eleventyConfig.addFilter("humanDate", dateObj => {
    return DateTime.fromJSDate(dateObj).toFormat("EEEE DDD");
  });

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

  // Limit posts
  //
  eleventyConfig.addFilter("limitposts", function(array, limit) {
    return array.slice(0, limit);
  });

  // CleanCSS
  // https://github.com/jakubpawlowicz/clean-css
  eleventyConfig.addFilter("cssmin", function(code) {
    const cleanCSSOptions = {
      level: {
        1: {
          specialComments: false
        },
        2: {
          all: true
        }
      }
    };
    return new CleanCSS(cleanCSSOptions).minify(code).styles;
  });

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

  // HTMLMinifier
  // https://github.com/kangax/html-minifier
  eleventyConfig.addTransform("htmlmin", function(content, outputPath) {
    if (outputPath.indexOf(".html") > -1) {
      let minified = htmlmin.minify(content, {
        collapseWhitespace: true,
        processScripts: [
          'text/html',
          'application/ld+json'
        ],
        removeComments: true,
        useShortDoctype: true
      });
      return minified;
    }
    return content;
  });

  // Universal slug filter strips unsafe chars from URLs
  //
  eleventyConfig.addFilter("slugify", function(str) {
    return slugify(str, {
      lower: true,
      replacement: "-",
      remove: /[*+~.·,()'"`´%!?¿:@]/g
    });
  });

  // Markdown
  //
  let markdownIt = require("markdown-it");
  let markdownItOptions = {
    html: true,
    breaks: true,
    linkify: true
  };
  let markdownItAnchor = require("markdown-it-anchor");
  let markdownItAnchorOptions = {
    permalink: false
  };
  let markdownItAttrs = require("markdown-it-attrs");
  let markdownItAttrsOptions = {
    leftDelimiter: '{',
    rightDelimiter: '}',
    allowedAttributes: []
  };

  let markdownLib = markdownIt(markdownItOptions).use(markdownItAnchor, markdownItAnchorOptions).use(markdownItAttrs, markdownItAttrsOptions)
  eleventyConfig.setLibrary("md", markdownLib);

  // Exposes markdownit code pair for use with yaml data
  eleventyConfig.addPairedShortcode("markdownit", function(content) {
    return markdownLib.render(content);
  });

  // Data deep merge
  // https://www.11ty.dev/docs/data-deep-merge/
  eleventyConfig.setDataDeepMerge(true);

  // PassthroughCopy
  // https://www.11ty.dev/docs/copy/
  eleventyConfig.addPassthroughCopy("_headers");
  eleventyConfig.addPassthroughCopy("_redirects");
  eleventyConfig.addPassthroughCopy("src/admin");
  eleventyConfig.addPassthroughCopy("src/assets");
  eleventyConfig.addPassthroughCopy('src/BingSiteAuth.xml');
  eleventyConfig.addPassthroughCopy("src/favicon.ico");
  eleventyConfig.addPassthroughCopy("src/google3a9cfc1297810bcd.html");
  eleventyConfig.addPassthroughCopy("src/manifest.webmanifest");
  eleventyConfig.addPassthroughCopy("src/robots.txt");
  eleventyConfig.addPassthroughCopy("src/u");

  return {
    dataTemplateEngine: "njk",
    dir: {
      data: "_data",
      input: "src",
      output: "dist"
    },
    htmlTemplateEngine: "njk",
    markdownTemplateEngine: "liquid",
    passthroughFileCopy: true,
    templateFormats: ["md", "njk", "html", "liquid"]
  };

};