create-xdm-node.ts

import { createContentDigest } from 'gatsby-core-utils';
import graymatter from 'gray-matter';
import rehypeRaw from 'rehype-raw';
import remarkAutolinkHeadings from 'remark-autolink-headings';
import remarkExternalLinks from 'remark-external-links';
import remarkFrontmatter from 'remark-frontmatter';
import gfm from 'remark-gfm';
import remarkMath from 'remark-math';
import { remarkMdxFrontmatter } from 'remark-mdx-frontmatter';
import remarkSlug from 'remark-slug';
import remarkExtractAST from '../mdx-plugins/extract-mdast';
import customRehypeKatex from '../mdx-plugins/rehype-math';
import rehypeSnippets from '../mdx-plugins/rehype-snippets';
import remarkToC from '../mdx-plugins/remark-toc';
import getGatsbyImage from './wrapped-gatsby-img-plugin';
import { xdm } from './xdm';

// todo: migrate to resolver for even better development performance

export async function createXdmNode({ id, node, content }, api) {
  let xdmNode: any = {
    id,
    children: [],
    parent: node.id,
    internal: {
      content: content,
      type: `Xdm`,
    },
  };

  let compiledResult;
  const tableOfContents = {};
  const mdast = { data: null };

  const gatsbyImage = getGatsbyImage({
    ...api,
    xdmNode,
  });

  try {
    compiledResult = await xdm.compile(
      content.replace(/<!--/g, '{/* ').replace(/-->/g, '*/}'),
      {
        remarkPlugins: [
          gfm,
          remarkMath,
          remarkFrontmatter,
          remarkMdxFrontmatter,
          [remarkExtractAST, { mdast }],
          remarkExternalLinks,
          [remarkToC, { tableOfContents }],
          remarkSlug,
          [
            remarkAutolinkHeadings,
            {
              linkProperties: {
                ariaHidden: 'true',
                tabIndex: -1,
                className: 'anchor before',
              },
              content: {
                type: 'mdxJsxFlowElement',
                name: 'HeaderLink',
              },
            },
          ],
          gatsbyImage,
        ],
        rehypePlugins: [
          [
            rehypeRaw,
            {
              passThrough: [
                'mdxjsEsm',
                'mdxFlowExpression',
                'mdxTextExpression',
                'mdxJsxFlowElement',
                'mdxJsxTextElement',
              ],
            },
          ],
          customRehypeKatex,
          rehypeSnippets,
        ],
        outputFormat: 'function-body',
      }
    );
    compiledResult = String(compiledResult);
  } catch (e) {
    // add the path of the file to simplify debugging error messages
    e.message += `${node.absolutePath}: ${e.message}`;
    throw e;
  }

  // // extract all the exports
  // const { frontmatter, ...nodeExports } = extractExports(
  //   code,
  //   node.absolutePath
  // )

  const langSecOc = (content.match(/<LanguageSection/g) || []).length;
  const cppOc = (content.match(/<CPPSection/g) || []).length;
  const javaOc = (content.match(/<JavaSection/g) || []).length;
  const pyOc = (content.match(/<PySection/g) || []).length;
  if (langSecOc < Math.max(cppOc, javaOc, pyOc)) {
    throw new Error(
      `${node.absolutePath}: # lang sections = ${langSecOc} < max(${cppOc},${javaOc},${pyOc})`
    );
  }
  const { data: frontmatter } = graymatter(content);
  xdmNode = {
    ...xdmNode,
    body: compiledResult,
    frontmatter,
    isIncomplete: content.indexOf('<IncompleteSection') !== -1,
    cppOc,
    javaOc,
    pyOc,
    toc: tableOfContents,
    mdast: mdast.data,
  };

  // xdmNode.exports = nodeExports

  // Add path to the markdown file path
  if (node.internal.type === `File`) {
    xdmNode.fileAbsolutePath = node.absolutePath;
  }

  xdmNode.internal.contentDigest = createContentDigest(xdmNode);

  return xdmNode;
}