.eleventy.js

const fs = require('fs')
const moment = require('moment')
const syntaxHighlight = require('@11ty/eleventy-plugin-syntaxhighlight')
const embedYouTube = require('eleventy-plugin-youtube-embed')
const markdownIt = require('markdown-it')
const markdownItLinkAttr = require('markdown-it-link-attributes')
const markdownItAnchor = require('markdown-it-anchor')
const markdownItAttrs = require('markdown-it-attrs')
const typesetPlugin = require('eleventy-plugin-typeset')
const lazyImagesPlugin = require('eleventy-plugin-lazyimages')
const pluginRss = require('@11ty/eleventy-plugin-rss')
const pluginEmbedTweet = require('eleventy-plugin-embed-tweet')

module.exports = function (eleventyConfig) {
  /**
   * Opts in to a full deep merge when combining the Data Cascade.
   *
   * @link https://www.11ty.dev/docs/data-deep-merge/#data-deep-merge
   */
  eleventyConfig.setDataDeepMerge(true)

  /**
   * Add custom watch targets
   *
   * @link https://www.11ty.dev/docs/config/#add-your-own-watch-targets
   */
  eleventyConfig.addWatchTarget('./src/assets/')

  /**
   * Passthrough file copy
   *
   * @link https://www.11ty.io/docs/copy/
   */
  eleventyConfig.addPassthroughCopy('./src/favicon.ico')

  /**
   * Add filters
   *
   * @link https://www.11ty.io/docs/filters/
   */
  eleventyConfig.addFilter('dateReadable', (date) => {
    return moment(date).format('LL')
  })

  eleventyConfig.addFilter('limit', function (array, limit) {
    if (!limit) {
      return array
    }
    return array.slice(0, limit)
  })

  /**
   * Add shortcodes
   *
   * @link https://www.11ty.io/docs/shortcodes/
   */
  eleventyConfig.addShortcode('excerpt', (article) => {
    if (!article.hasOwnProperty('templateContent')) {
      console.warn(
        'Failed to extract excerpt: Document has no property "templateContent".'
      )
      return null
    }

    let excerpt = null
    const content = article.templateContent

    // The start and end separators to try and match to extract the excerpt
    const separatorsList = [
      { start: '<!-- Excerpt Start -->', end: '<!-- Excerpt End -->' },
      { start: '<p>', end: '</p>' },
    ]

    separatorsList.some((separators) => {
      const startPosition = content.indexOf(separators.start)
      const endPosition = content.indexOf(separators.end)

      if (startPosition !== -1 && endPosition !== -1) {
        excerpt = content
          .substring(startPosition + separators.start.length, endPosition)
          .trim()
        return true // Exit out of array loop on first match
      }
    })

    return excerpt
  })
  /**
   * Add Transforms
   *
   * @link https://www.11ty.io/docs/config/#transforms
   */
  if (process.env.ELEVENTY_ENV === 'production') {
    eleventyConfig.addTransform('htmlmin', require('./utils/htmlmin.js'))
  }

  /**
   * Override BrowserSync Server options
   *
   * @link https://www.11ty.dev/docs/config/#override-browsersync-server-options
   */
  eleventyConfig.setBrowserSyncConfig({
    notify: true,
    snippetOptions: {
      rule: {
        match: /<\/head>/i,
        fn: function (snippet, match) {
          return snippet + match
        },
      },
    },
    // Set local server 404 fallback
    callbacks: {
      ready: function (err, browserSync) {
        const content_404 = fs.readFileSync('dist/404/index.html')

        browserSync.addMiddleware('*', (req, res) => {
          // Provides the 404 content without redirect.
          res.write(content_404)
          res.end()
        })
      },
    },
  })

  /**
   * Set markdown libraries
   *
   * @link https://www.11ty.dev/docs/languages/markdown/#optional-set-your-own-library-instance
   */
  eleventyConfig.setLibrary(
    'md',
    markdownIt({ html: true })
      .use(markdownItAttrs)
      .use(markdownItAnchor, {
        permalink: true,
        permalinkSymbol: '<i data-feather="link" class="link"></i>',
      })
      .use(markdownItLinkAttr, {
        // Make external links open in a new tab.
        pattern: /^https?:\/\//,
        attrs: {
          target: '_blank',
          rel: 'noopener noreferrer',
        },
      })
  )

  /**
   * Add plugins
   *
   * @link https://www.11ty.dev/docs/plugins/
   */
  eleventyConfig.addPlugin(syntaxHighlight, {
    templateFormats: ['md'],
  })
  eleventyConfig.addPlugin(embedYouTube, {
    allowFullscreen: false,
  })
  eleventyConfig.addPlugin(typesetPlugin())
  eleventyConfig.addPlugin(lazyImagesPlugin, {
    transformImgPath: (imgPath) => `./src${imgPath}`,
  })
  eleventyConfig.addPlugin(pluginRss)
  eleventyConfig.addPlugin(pluginEmbedTweet)

  return {
    dir: {
      input: 'src',
      output: 'dist',
      layouts: 'layouts',
      includes: 'includes',
    },
    passthroughFileCopy: true,
    templateFormats: ['njk', 'md'],
    htmlTemplateEngine: 'njk',
    markdownTemplateEngine: 'njk',
  }
}