@nuxtjs/mdc/dist/runtime/parser/toc.js

Nuxt MDC module

import { flattenNode, flattenNodeText } from "../utils/ast.js";
const TOC_TAGS = ["h2", "h3", "h4", "h5", "h6"];
const TOC_TAGS_DEPTH = TOC_TAGS.reduce((tags, tag) => {
  tags[tag] = Number(tag.charAt(tag.length - 1));
  return tags;
}, {});
const getHeaderDepth = (node) => TOC_TAGS_DEPTH[node.tag];
const getTocTags = (depth) => {
  if (depth < 1 || depth > 5) {
    console.log(`\`toc.depth\` is set to ${depth}. It should be a number between 1 and 5. `);
    depth = 1;
  }
  return TOC_TAGS.slice(0, depth);
};
function nestHeaders(headers) {
  if (headers.length <= 1) {
    return headers;
  }
  const toc = [];
  let parent;
  headers.forEach((header) => {
    if (!parent || header.depth <= parent.depth) {
      header.children = [];
      parent = header;
      toc.push(header);
    } else {
      parent.children.push(header);
    }
  });
  toc.forEach((header) => {
    if (header.children?.length) {
      header.children = nestHeaders(header.children);
    } else {
      delete header.children;
    }
  });
  return toc;
}
export function generateFlatToc(body, options) {
  const { searchDepth, depth, title = "" } = options;
  const tags = getTocTags(depth);
  const headers = flattenNode(body, searchDepth).filter((node) => tags.includes(node.tag || ""));
  const links = headers.map((node) => ({
    id: node.props?.id,
    depth: getHeaderDepth(node),
    text: flattenNodeText(node)
  }));
  return {
    title,
    searchDepth,
    depth,
    links
  };
}
export function generateToc(body, options) {
  const toc = generateFlatToc(body, options);
  toc.links = nestHeaders(toc.links);
  return toc;
}