Update .eleventy.js

.eleventy.js

@@ -1,45 +1,49 @@
 const tocPlugin = require('eleventy-plugin-toc');
-const markdownIt = require("markdown-it");
-const CleanCSS = require("clean-css");
+const markdownIt = require('markdown-it');
+const CleanCSS = require('clean-css');
+const markdownItAnchor = require('markdown-it-anchor');
 
 module.exports = function (eleventyConfig) {
+  // Passthrough copy for assets
+  eleventyConfig.addPassthroughCopy('docs/assets');
 
-  eleventyConfig.addPassthroughCopy("docs/assets");
-  eleventyConfig.addFilter("cssmin", function(code) {
+  // CSS minification filter
+  eleventyConfig.addFilter('cssmin', function (code) {
     return new CleanCSS({}).minify(code).styles;
   });
-  // This filter is used for deriving the chapter names
-  // from data in chapters.json
+
+  // Heading filter for deriving chapter names
   eleventyConfig.addFilter('heading', function (str) {
-    return str.replace(/[_;\\/:*?\"<>|&']/g, " ");
+    return str.replace(/[_;\\/:*?\"<>|&']/g, ' ');
+  });
+
+  // Markdown rendering filter
+  const mdIt = markdownIt({
+    html: true,
+    linkify: true,
+  }).use(markdownItAnchor, {
+    permalink: true,
+    permalinkBefore: false,
+    permalinkClass: 'direct-link',
+    permalinkSymbol: '#',
+    level: [1, 2],
   });
 
-  // Filter for linking to section headers
-  // and displaying chapters in a page
-  let markdownItAnchor = require("markdown-it-anchor");
-  let mdIt = markdownIt({
-      html: true,
-      linkify: true
-    })
-    .use(markdownItAnchor, {
-      permalink: true,
-      permalinkBefore: false,
-      permalinkClass: "direct-link",
-      permalinkSymbol: "#",
-      level: [1, 2]
-    });
-  eleventyConfig.addFilter("markdown", function(code) {
-      if(code) {
-        return mdIt.render(code);
-      }
+  eleventyConfig.addFilter('markdown', function (code) {
+    return code ? mdIt.render(code) : '';
   });
-  eleventyConfig.setLibrary("md", mdIt);
+
+  // Set Markdown library
+  eleventyConfig.setLibrary('md', mdIt);
+
+  // Add TOC plugin
   eleventyConfig.addPlugin(tocPlugin);
 
+  // Configuration for Eleventy
   return {
     dir: {
       input: 'docs',
-      output: 'docs/_site'
-    }
-  }
-};
+      output: 'docs/_site',
+    },
+  };
+};