.eleventy.js

const { DateTime } = require("luxon");
const readingTime = require("eleventy-plugin-reading-time");
const pluginRss = require("@11ty/eleventy-plugin-rss");
const syntaxHighlight = require("@11ty/eleventy-plugin-syntaxhighlight");
const htmlmin = require("html-minifier");
const fs = require("fs");
const path = require("path");

const isDev = process.env.ELEVENTY_ENV === "development";
const isProd = process.env.ELEVENTY_ENV === "production";

const manifestPath = path.resolve(__dirname, "public", "assets", "manifest.json");

const manifest = isDev
  ? {
      "main.js": "/assets/main.js",
      "main.css": "/assets/main.css"
    }
  : JSON.parse(fs.readFileSync(manifestPath, { encoding: "utf8" }));

module.exports = function (eleventyConfig) {
  eleventyConfig.addPlugin(readingTime);
  eleventyConfig.addPlugin(pluginRss);
  eleventyConfig.addPlugin(syntaxHighlight);

  // setup mermaid markdown highlighter
  const highlighter = eleventyConfig.markdownHighlighter;
  eleventyConfig.addMarkdownHighlighter((str, language) => {
    if (language === "mermaid") {
      return `<pre class="mermaid">${str}</pre>`;
    }
    return highlighter(str, language);
  });

  eleventyConfig.setDataDeepMerge(true);
  eleventyConfig.addPassthroughCopy({ "src/images": "images" });
  eleventyConfig.setBrowserSyncConfig({ files: [manifestPath] });

  eleventyConfig.addShortcode("bundledcss", function () {
    return manifest["main.css"] ? `<link href="${manifest["main.css"]}" rel="stylesheet" />` : "";
  });

  eleventyConfig.addShortcode("bundledjs", function () {
    return manifest["main.js"] ? `<script src="${manifest["main.js"]}"></script>` : "";
  });

  eleventyConfig.addFilter("excerpt", (post) => {
    const content = post.replace(/(<([^>]+)>)/gi, "");
    return content.substr(0, content.lastIndexOf(" ", 200)) + "...";
  });

  eleventyConfig.addFilter("readableDate", (dateObj) => {
    return DateTime.fromJSDate(dateObj, { zone: "utc" }).toFormat("dd LLL yyyy");
  });

  eleventyConfig.addFilter("htmlDateString", (dateObj) => {
    return DateTime.fromJSDate(dateObj, { zone: "utc" }).toFormat("yyyy-LL-dd");
  });

  eleventyConfig.addFilter("dateToIso", (dateString) => {
    return new Date(dateString).toISOString();
  });

  eleventyConfig.addFilter("head", (array, n) => {
    if (n < 0) {
      return array.slice(n);
    }

    return array.slice(0, n);
  });

  eleventyConfig.addCollection("tagList", function (collection) {
    let tagSet = new Set();
    collection.getAll().forEach(function (item) {
      if ("tags" in item.data) {
        let tags = item.data.tags;

        tags = tags.filter(function (item) {
          switch (item) {
            case "all":
            case "nav":
            case "post":
            case "posts":
            case "tips":
              return false;
          }

          return true;
        });

        for (const tag of tags) {
          tagSet.add(tag);
        }
      }
    });

    return [...tagSet];
  });

  eleventyConfig.addFilter("pageTags", (tags) => {
    const generalTags = ["all", "nav", "post", "posts", "tips"];

    return tags
      .toString()
      .split(",")
      .filter((tag) => {
        return !generalTags.includes(tag);
      });
  });

  eleventyConfig.addTransform("htmlmin", function (content, outputPath) {
    if (outputPath && outputPath.endsWith(".html") && isProd) {
      return htmlmin.minify(content, {
        removeComments: true,
        collapseWhitespace: true,
        useShortDoctype: true
      });
    }

    return content;
  });

  return {
    dir: {
      input: "src",
      output: "public",
      includes: "includes",
      data: "data",
      layouts: "layouts",
      passthroughFileCopy: true,
      templateFormats: ["html", "njk", "md"],
      htmlTemplateEngine: "njk",
      markdownTemplateEngine: "njk"
    }
  };
};