.eleventy.js

const { DateTime } = require('luxon');
const fs = require('fs');
const pluginRss = require('@11ty/eleventy-plugin-rss');
const pluginSyntaxHighlight = require('@11ty/eleventy-plugin-syntaxhighlight');
const pluginNavigation = require('@11ty/eleventy-navigation');
const markdownIt = require('markdown-it');
const markdownItAnchor = require('markdown-it-anchor');
module.exports = function (eleventyConfig) {
  eleventyConfig.addPlugin(pluginRss);
  eleventyConfig.addPlugin(pluginSyntaxHighlight);
  eleventyConfig.addPlugin(pluginNavigation);
  eleventyConfig.setDataDeepMerge(true);
  eleventyConfig.addLayoutAlias('post', 'layouts/post.njk');

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

    return array.slice(0, n);
  });
  eleventyConfig.addFilter('min', (...numbers) => {
    return Math.min.apply(null, numbers);
  });

  eleventyConfig.addFilter('filterTagList', (tags) => {
    return (tags || []).filter(
      (tag) => ['all', 'nav', 'post', 'posts'].indexOf(tag) === -1
    );
  });
  eleventyConfig.addCollection('tagList', function (collection) {
    let tagSet = new Set();
    collection.getAll().forEach((item) => {
      (item.data.tags || []).forEach((tag) => tagSet.add(tag));
    });
    return [...tagSet];
  });
  eleventyConfig.addPassthroughCopy('img');
  eleventyConfig.addPassthroughCopy('css');
  let markdownLibrary = markdownIt({
    html: true,
    breaks: true,
    linkify: true,
  }).use(markdownItAnchor, {
    permalink: true,
    permalinkClass: 'direct-link',
    permalinkSymbol: '#',
  });
  eleventyConfig.setLibrary('md', markdownLibrary);
  eleventyConfig.setBrowserSyncConfig({
    callbacks: {
      ready: function (err, browserSync) {
        const content_404 = fs.readFileSync('_site/404.html');

        browserSync.addMiddleware('*', (req, res) => {
          res.writeHead(404, { 'Content-Type': 'text/html; charset=UTF-8' });
          res.write(content_404);
          res.end();
        });
      },
    },
    ui: false,
    ghostMode: false,
  });
  return {
    templateFormats: ['md', 'njk', 'html', 'liquid'],
    pathPrefix: '/',
    markdownTemplateEngine: 'njk',
    htmlTemplateEngine: 'njk',
    dataTemplateEngine: false,
    dir: {
      input: '.',
      includes: '_includes',
      data: '_data',
      output: '_site',
    },
  };
};