remark-plugins.mjs

import { findAfter } from "unist-util-find-after";
import { visit } from "unist-util-visit";


export function remarkSectionize() {
  return (tree) => {
    const MAX_HEADING_DEPTH = 6;
    for (let depth = MAX_HEADING_DEPTH; depth > 0; depth--) {
      visit(
        tree,
        (node) => node.type === "heading" && node.depth === depth,
        (node, index, parent) => {
          const start = node;
          const startIndex = index;
          const depth = start.depth;

          const isEnd = (node) =>
            (node.type === "heading" && node.depth <= depth) ||
            node.type === "export";
          const end = findAfter(parent, start, isEnd);
          const endIndex = parent.children.indexOf(end);

          const between = parent.children.slice(
            startIndex,
            endIndex > 0 ? endIndex : undefined
          );

          const textNode = node.children.at(-1);
          const text = textNode.value
            .trimEnd()
            .toLowerCase()
            .split(" ")
            .join("-");

          const section = {
            type: "div",
            depth: depth,
            children: between,
            data: {
              hName: "div",
              hProperties: {
                id: text,
              },
            },
          };

          parent.children.splice(startIndex, section.children.length, section);
        }
      );
    }
  };
}