.eleventy.js

const util = require('util');
const syntaxHighlight = require("@11ty/eleventy-plugin-syntaxhighlight");
const pluginRss = require("@11ty/eleventy-plugin-rss");
const { DateTime } = require("luxon");
const fs = require("fs");
const NOT_FOUND_PATH = "_site/404.html";

const getPostCount = (tag, posts) => {
  return posts.filter((post) => post.data.tags?.includes(tag)).length
}

const arrayIncludesTag = (tag, arr) => {
  return arr.some((item) => item.title === tag.title)
}

const getTags = (item) => {
  return item.data.tags.filter(function (item) {
    switch (item) {
      // this list should match the `filter` list in tags.njk
      case 'all':
      case 'nav':
      case 'post':
      case 'posts':
      case 'page':
        return false
    }

    return true
  })
}

module.exports = function (eleventyConfig) {

  eleventyConfig.addPlugin(syntaxHighlight);

  eleventyConfig.addPlugin(pluginRss);

  eleventyConfig.addFilter('console', function(value) {
      const str = util.inspect(value);
      return `<div style="white-space: pre-wrap;">${unescape(str)}</div>;`
  });

  eleventyConfig.addFilter('dump', obj => {
    return util.inspect(obj)
  });

  eleventyConfig.addFilter("postDate", (dateObj) => {
    return DateTime.fromJSDate(dateObj).toLocaleString(DateTime.DATE_FULL);
  });

  eleventyConfig.addFilter("postDateTime", (dateObj) => {
    const shortdate = DateTime.fromJSDate(dateObj).toISODate(DateTime.DATE_SHORT)
    if (shortdate) {
      return shortdate.replace(/\//g, '-');
    } else {
      return '';
    }
  });

  eleventyConfig.addCollection("posts", function(collectionApi) {
      return collectionApi.getFilteredByGlob("src/posts/**/*.md");
  });

  eleventyConfig.addCollection('allTags', function (collection) {
    let tagSet = new Set()

    collection.getAll().forEach(function (item) {
      if ('tags' in item.data) {
        const tags = getTags(item)

        for (const tag of tags) {
          tagSet.add({
            title: tag,
            postCount: getPostCount(tag, collection.getFilteredByGlob("src/posts/**/*.md")),
          })
        }
      }
    })

    const arr = []
    const sortedTags = [...tagSet]
      .sort((a, b) => a.postCount - b.postCount)
      .reverse()

    sortedTags.forEach((tag) => {
      if (arrayIncludesTag(tag, arr)) return
      arr.push(tag)
    })

    return arr
  })

  eleventyConfig.addShortcode("year", () => `${new Date().getFullYear()}`);

  eleventyConfig.addPassthroughCopy("src/images");

  eleventyConfig.addShortcode("topcap", function(cloudinaryImageName) {
    return `
    <div class="top-cap">
      <img aria-hidden="true"
      src="https://res.cloudinary.com/chipcullen/image/upload/b_rgb:000000,c_scale,o_98,w_300/v1669146466/${cloudinaryImageName}.webp"
      srcset="https://res.cloudinary.com/chipcullen/image/upload/b_rgb:000000,c_scale,o_98,w_600/v1669146466/${cloudinaryImageName}.webp 600w,
        https://res.cloudinary.com/chipcullen/image/upload/b_rgb:000000,c_scale,o_98,w_800/v1669146466/${cloudinaryImageName}.webp 800w,
        https://res.cloudinary.com/chipcullen/image/upload/b_rgb:000000,c_scale,o_98,w_1200/v1669146466/${cloudinaryImageName}.webp 1200w"
      loading="lazy"
      sizes="40vw"
      alt="" />
    </div>`;
  });

  // for 404 page development
  eleventyConfig.setBrowserSyncConfig({
    callbacks: {
      ready: function(err, bs) {

        bs.addMiddleware("*", (req, res) => {
          if (!fs.existsSync(NOT_FOUND_PATH)) {
            throw new Error(`Expected a \`${NOT_FOUND_PATH}\` file but could not find one. Did you create a 404.html template?`);
          }

          const content_404 = fs.readFileSync(NOT_FOUND_PATH);
          // Add 404 http status code in request header.
          res.writeHead(404, { "Content-Type": "text/html; charset=UTF-8" });
          // Provides the 404 content without redirect.
          res.write(content_404);
          res.end();
        });
      }
    }
  });
  return {
    dir: {
      input: "src",
      output: "dist",
    },
    templateFormats: ["html", "md", "njk"],
    passthroughFileCopy: true,
  };
};