astro/packages/markdown/remark/src/remark-initialize-astro-data.ts

import type { VFile } from 'vfile';

export function remarkInitializeAstroData() {
	return function (tree: any, vfile: VFile) {
		if (!vfile.data.astro) {
			vfile.data.astro = { frontmatter: {} };
		}
	};
}