storybook/docs/snippets/common/storybook-main-md-html-indexer.js.mdx

```js
// .storybook/main.js

import { loadCsf } from '@storybook/csf-tools';
import { compile } from '@storybook/mdx2-csf';

const indexer = async (fileName, opts) => {
  const title = fileName
    .split('/')
    .pop()
    .replace(/\.(md|html)$/, '');

  // Convert Markdown into MDX
  const source = `
      import { Meta, Description } from '@storybook/blocks';

      <Meta title='${title}' />
      <Description>{require('${fileName}')}</Description>
  `;

  // Compile MDX into CSF
  const code = await compile(source, {});

  // Parse CSF component
  return loadCsf(code, { ...opts, fileName }).parse();
};

export default {
  storyIndexers: (indexers) => {
    return [
      {
        test: /\.(md|html)$/,
        indexer,
      },
      ...(indexers || []),
    ];
  },
};
```