.eleventy.js

const { DateTime } = require('luxon');
const pluginRss = require('@11ty/eleventy-plugin-rss');
const pluginSyntaxHighlight = require('@11ty/eleventy-plugin-syntaxhighlight');

module.exports = function(eleventyConfig) {
  eleventyConfig.addPlugin(pluginRss);
  eleventyConfig.addPlugin(pluginSyntaxHighlight);
  eleventyConfig.setDataDeepMerge(true);

  eleventyConfig.addLayoutAlias('post', 'layouts/post.njk');

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

  // https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#valid-date-string
  eleventyConfig.addFilter('htmlDateString', dateObj => {
    return DateTime.fromJSDate(dateObj).toFormat('yyyy-LL-dd');
  });

  // Get the first `n` elements of a collection.
  eleventyConfig.addFilter('head', (array, n) => {
    if (n < 0) {
      return array.slice(n);
    }

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

  eleventyConfig.addCollection('tagList', require('./_11ty/getTagList'));

  eleventyConfig.addPassthroughCopy('img');
  eleventyConfig.addPassthroughCopy('css');

  /* Markdown Plugins */
  let markdownIt = require('markdown-it');
  let markdownItAnchor = require('markdown-it-anchor');
  let options = {
    html: true,
    breaks: true,
    linkify: true
  };
  let opts = {
    permalink: true,
    permalinkClass: 'direct-link',
    permalinkSymbol: '#'
  };

  eleventyConfig.setLibrary('md', markdownIt(options).use(markdownItAnchor, opts));

  return {
    templateFormats: ['md', 'njk', 'html', 'liquid'],
    pathPrefix: '/',
    markdownTemplateEngine: 'liquid',
    htmlTemplateEngine: 'njk',
    dataTemplateEngine: 'njk',
    passthroughFileCopy: true,
    dir: {
      input: '.',
      includes: '_includes',
      data: '_data',
      output: 'dist'
    }
  };
};