contentlayer.config.ts

import { defineDocumentType, ComputedFields, makeSource } from 'contentlayer2/source-files';
import { writeFileSync } from 'fs';
import readingTime from 'reading-time';
import { slug } from 'github-slugger';
import { visit } from 'unist-util-visit';
import path from 'path';
import { fromHtmlIsomorphic } from 'hast-util-from-html-isomorphic';
// Remark packages
import remarkGfm from 'remark-gfm';
import remarkMath from 'remark-math';
import {
  remarkExtractFrontmatter,
  remarkCodeTitles,
  remarkImgToJsx,
  extractTocHeadings,
} from 'pliny/mdx-plugins/index.js';
// Rehype packages
import rehypeSlug from 'rehype-slug';
import rehypeAutolinkHeadings from 'rehype-autolink-headings';
import rehypeKatex from 'rehype-katex';
import rehypeCitation from 'rehype-citation';
import rehypePresetMinify from 'rehype-preset-minify';
import siteMetadata from './data/siteMetadata';
import { allCoreContent, sortPosts } from 'pliny/utils/contentlayer.js';

const root = process.cwd();
const isProduction = process.env.NODE_ENV === 'production';

const getRehypeMdxCodeMeta = () => {
  return (options = {}) => {
    return (tree) => {
      visit(tree, 'element', visitor);
    };

    function visitor(node, index, parentNode) {
      if (node.tagName === 'code' && node.data && node.data.meta) {
        const blocks = node.data.meta.split(' ');

        node.properties = blocks.reduce((props, block) => {
          const [prop, value] = block.split('=');

          if (typeof value === 'undefined') {
            props.line = prop;

            return props;
          }

          props[prop] = value;

          return props;
        }, node.properties);
      }
    }
  };
};

// heroicon mini link
const icon = fromHtmlIsomorphic(
  `
  <span class="content-header-link">
  <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="currentColor" className="w-5 h-5 linkicon">
  <path d="M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z" />
  <path d="M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z" />
  </svg>
  </span>
`,
  { fragment: true }
);

const computedFields: ComputedFields = {
  readingTime: { type: 'json', resolve: (doc) => readingTime(doc.body.raw) },
  slug: {
    type: 'string',
    resolve: (doc) => doc._raw.flattenedPath.replace(/^.+?(\/)/, ''),
  },
  path: {
    type: 'string',
    resolve: (doc) => doc._raw.flattenedPath,
  },
  filePath: {
    type: 'string',
    resolve: (doc) => doc._raw.sourceFilePath,
  },
  toc: { type: 'string', resolve: (doc) => extractTocHeadings(doc.body.raw) },
};

/**
 * Count the occurrences of all tags across blog posts and write to json file
 */
function createTagCount(allBlogs) {
  const tagCount: Record<string, number> = {};
  allBlogs.forEach((file) => {
    if (file.tags && (!isProduction || file.draft !== true)) {
      file.tags.forEach((tag) => {
        const formattedTag = slug(tag);
        if (formattedTag in tagCount) {
          tagCount[formattedTag] += 1;
        } else {
          tagCount[formattedTag] = 1;
        }
      });
    }
  });
  writeFileSync('./app/tag-data.json', JSON.stringify(tagCount));
}

function createSearchIndex(allBlogs) {
  if (siteMetadata?.search?.provider === 'kbar' && siteMetadata.search.kbarConfig.searchDocumentsPath) {
    writeFileSync(
      `public/${siteMetadata.search.kbarConfig.searchDocumentsPath}`,
      JSON.stringify(allCoreContent(sortPosts(allBlogs)))
    );
    console.log('Local search index generated...');
  }
}

export const Blog = defineDocumentType(() => ({
  name: 'Blog',
  filePathPattern: 'writing/**/*.mdx',
  contentType: 'mdx',
  fields: {
    title: { type: 'string', required: true },
    date: { type: 'date', required: true },
    tags: { type: 'list', of: { type: 'string' }, default: [] },
    lastmod: { type: 'date' },
    draft: { type: 'boolean' },
    summary: { type: 'string' },
    images: { type: 'json' },
    authors: { type: 'list', of: { type: 'string' } },
    layout: { type: 'string' },
    bibliography: { type: 'string' },
    canonicalUrl: { type: 'string' },
    topic: { type: 'string' },
    order: { type: 'number' },
    skip: { type: 'boolean' },
  },
  computedFields: {
    ...computedFields,
    structuredData: {
      type: 'json',
      resolve: (doc) => ({
        '@context': 'https://schema.org',
        '@type': 'BlogPosting',
        headline: doc.title,
        datePublished: doc.date,
        dateModified: doc.lastmod || doc.date,
        description: doc.summary,
        image: doc.images ? doc.images[0] : siteMetadata.socialBanner,
        url: `${siteMetadata.siteUrl}/${doc._raw.flattenedPath}`,
      }),
    },
  },
}));

export const Authors = defineDocumentType(() => ({
  name: 'Authors',
  filePathPattern: 'authors/**/*.mdx',
  contentType: 'mdx',
  fields: {
    name: { type: 'string', required: true },
    avatar: { type: 'string' },
    occupation: { type: 'string' },
    company: { type: 'string' },
    email: { type: 'string' },
    twitter: { type: 'string' },
    linkedin: { type: 'string' },
    github: { type: 'string' },
    layout: { type: 'string' },
  },
  computedFields,
}));

export default makeSource({
  contentDirPath: 'data',
  documentTypes: [Blog, Authors],
  mdx: {
    cwd: process.cwd(),
    remarkPlugins: [remarkExtractFrontmatter, remarkGfm, remarkCodeTitles, remarkMath, remarkImgToJsx],
    rehypePlugins: [
      rehypeSlug,
      [
        rehypeAutolinkHeadings,
        {
          behavior: 'prepend',
          headingProperties: {
            className: ['content-header'],
          },
          content: icon,
        },
      ],
      rehypeKatex,
      getRehypeMdxCodeMeta(),
      [rehypeCitation, { path: path.join(root, 'data') }],
      rehypePresetMinify,
    ],
  },
  onSuccess: async (importData) => {
    const { allBlogs } = await importData();
    createTagCount(allBlogs);
    createSearchIndex(allBlogs);
  },
});