mdsvex.config.js

import rehypeAutolinkHeadings from "rehype-autolink-headings";
import rehypeExternalLinks from "rehype-external-links";
import rehypeSlug from "rehype-slug";

import { defineMDSveXConfig as defineConfig } from "mdsvex";

const config = defineConfig({
  extensions: [".md"],
  rehypePlugins: [
    rehypeExternalLinks,
    rehypeSlug,
    [
      rehypeAutolinkHeadings,
      {
        behavior: "prepend",
        properties: { className: ["heading-link"], title: "Permalink", ariaHidden: "true" },
        content: {
          type: "element",
          tagName: "span",
          properties: {},
          children: [
            {
              type: "text",
              value:
                '<svg xmlns="http://www.w3.org/2000/svg" width="25" height="25" viewBox="0 0 448 512"><path fill="currentColor" d="M181.3 32.4c17.4 2.9 29.2 19.4 26.3 36.8l-9.8 58.8h95.1l11.5-69.3c2.9-17.4 19.4-29.2 36.8-26.3s29.2 19.4 26.3 36.8l-9.7 58.8H416c17.7 0 32 14.3 32 32s-14.3 32-32 32h-68.9l-21.3 128H384c17.7 0 32 14.3 32 32s-14.3 32-32 32h-68.9l-11.5 69.3c-2.9 17.4-19.4 29.2-36.8 26.3s-29.2-19.4-26.3-36.8l9.8-58.7h-95.2l-11.5 69.3c-2.9 17.4-19.4 29.2-36.8 26.3s-29.2-19.4-26.3-36.8l9.7-58.9H32c-17.7 0-32-14.3-32-32s14.3-32 32-32h68.9l21.3-128H64c-17.7 0-32-14.3-32-32s14.3-32 32-32h68.9l11.5-69.3c2.9-17.4 19.4-29.2 36.8-26.3zm5.8 159.6l-21.3 128h95.1l21.3-128h-95.1z"/></svg>'
            }
          ]
        }
      }
    ]
  ],
  smartypants: {
    dashes: "oldschool"
  }
});

export default config;