.eleventy.js

const yaml = require("js-yaml");
const { DateTime } = require("luxon");
// const syntaxHighlight = require("@11ty/eleventy-plugin-syntaxhighlight");
const timeToRead = require("eleventy-plugin-time-to-read");
const lazyImagesPlugin = require("eleventy-plugin-lazyimages");
const htmlmin = require("html-minifier");
const searchFilter = require("./src/filters/searchFilter");
const markdownIt = require("markdown-it");
const markdownItMark = require("markdown-it-mark");
const markdownItFootnote = require("markdown-it-footnote");

module.exports = function (eleventyConfig) {

  // overwrite markdown-it options
  let options = {
    html: true,
    breaks: true
  };
  eleventyConfig.setLibrary("md", markdownIt(options));

  // support ==content== to <mark>content</mark>
  eleventyConfig.amendLibrary("md", mdLib => mdLib.use(markdownItMark));

  eleventyConfig.amendLibrary("md", mdLib => mdLib.use(markdownItFootnote));

  // Disable automatic use of your .gitignore
  eleventyConfig.setUseGitIgnore(false);

  // instead of overriding, merge data cascade (e.g. frontmatter) between templates & files (doc: https://www.11ty.dev/docs/data-deep-merge/)
  eleventyConfig.setDataDeepMerge(true);

  // 404 page sync when eleventy --serve.
  // https://www.11ty.dev/docs/quicktips/not-found/

  // Current Year (global custom data, doc: https://www.11ty.dev/docs/data-global-custom/)
  eleventyConfig.addGlobalData(
    "currentYear",
    async () => {
      return (new Date()).getFullYear();
    }
  );

  // human readable date
  eleventyConfig.addFilter("readableDate", (dateObj) => {
    return DateTime.fromJSDate(dateObj, { zone: "utc" }).toFormat("DD");
  });

  // date to yyyy-MM-dd
  eleventyConfig.addFilter("dateFormat", (dateObj) => {
    return DateTime.fromJSDate(dateObj, { zone: "utc" }).toFormat("yyyy-MM-dd");
  });

  // search
  eleventyConfig.addFilter("search", searchFilter);

  eleventyConfig.addCollection("post", collection => {
    return [...collection.getFilteredByGlob("./src/collections/post/*.md")];
  });

  // Syntax Highlighting for Code blocks
  // eleventyConfig.addPlugin(syntaxHighlight);

  // Time to read content
  eleventyConfig.addPlugin(timeToRead);

  // Image Lazy Loading
  eleventyConfig.addPlugin(lazyImagesPlugin, {
    imgSelector: ".single-article img", // only post images
    // preferNativeLazyLoad: false,
    // cacheFile: '', // Pass an empty string to turn off the cache.
  });

  // To Support .yaml Extension in _data (more readable)
  // You may remove this if you prefer JSON
  eleventyConfig.addDataExtension("yaml", (contents) =>
    yaml.safeLoad(contents)
  );

  // Add Tailwind Output CSS as Watch Target
  eleventyConfig.addWatchTarget("./src/static/css/main.scss");

  // Copy Static Files to /_Site
  eleventyConfig.addPassthroughCopy({
    "./src/static/fonts/*": "./static/fonts/",
    "./src/admin/config.yml": "./admin/config.yml",
    "./src/static/js/footer.js": "./static/js/footer.js",
    "./src/static/js/search.js": "./static/js/search.js",
    "./src/static/js/elasticlunr.min.js": "./static/js/elasticlunr.min.js",
  });

  // Katex Files (CSS use CDN)
  eleventyConfig.addPassthroughCopy({
    "./node_modules/katex/dist/katex.min.js": "./static/js/katex.min.js",
    "./node_modules/katex/dist/contrib/auto-render.min.js":
      "./static/js/auto-render.min.js",
  });

  // TOC Files (CSS use CDN)
  eleventyConfig.addPassthroughCopy({
    "./src/static/js/toc.js": "./static/js/toc.js",
  });

  // PrismJS Files
  eleventyConfig.addPassthroughCopy({
    "./src/static/css/lib/prism.css": "./static/css/prism.css", // customized
    // "./node_modules/prismjs/themes/prism-tomorrow.css": "./static/css/prism.css", // only for basic languages
    "./node_modules/prismjs/plugins/line-numbers/prism-line-numbers.css":
      "./static/css/prism-line-numbers.css",
    "./node_modules/prismjs/plugins/line-numbers/prism-line-numbers.min.js":
      "./static/js/prism-line-numbers.min.js",
    "./src/static/js/prism.js": "./static/js/prism.js",
  });

  // Copy Image Folder to /_site
  eleventyConfig.addPassthroughCopy("./src/static/img");

  // Copy favicon to route of /_site
  eleventyConfig.addPassthroughCopy("./src/favicon.ico");

  // Custom Filter: split()
  eleventyConfig.addFilter("split", function (str, seperator) {
    return str.split(seperator);
  });
  // Custom Filter: includes()
  eleventyConfig.addFilter("includes", function (array, item) {
    return array.includes(item);
  });
  // Custom Filter: substring()
  eleventyConfig.addFilter("substring", function (str, start, end) {
    return str.substring(start, end);
  });
  // Custom Filter: indexOf()
  eleventyConfig.addFilter("indexOf", function (array, indexItem) {
    return array.indexOf(indexItem);
  });

  // // Custom Filter: push()
  // eleventyConfig.addFilter("push", function(array, item) {
  //  return array.push(item);
  // });
  // // Custom Filter: pop()
  // eleventyConfig.addFilter("pop", function(array, item) {
  //  return array.pop(item);
  // });

  // Minify HTML
  eleventyConfig.addTransform("htmlmin", function (content, outputPath) {
    // Eleventy 1.0+: use this.inputPath and this.outputPath instead
    if (outputPath.endsWith(".html")) {
      let minified = htmlmin.minify(content, {
        useShortDoctype: true,
        removeComments: true,
        collapseWhitespace: true,
      });
      return minified;
    }
    return content;
  });

  return {
    dir: {
      // input directory
      input: "src",
      // ⚠️ These values are relative to input directory, i.e.: src/
      includes: "_includes",
      layouts: "_includes/layouts",
      data: "_data", // global data files

      // output directory
      output: "_site",
    },

    // Let Eleventy transform HTML files as nunjucks, so we can use .html instead of .njk
    htmlTemplateEngine: "njk",
    
    // use njk as the default template engine for .md files
    markdownTemplateEngine: "njk"
  };
};