astro/packages/integrations/mdx/src/rehype-apply-frontmatter-export.ts
2023-09-14 20:05:38 +08:00

49 lines
1.8 KiB
TypeScript

import { InvalidAstroDataError } from '@astrojs/markdown-remark';
import { safelyGetAstroData } from '@astrojs/markdown-remark/dist/internal.js';
import type { VFile } from 'vfile';
import { jsToTreeNode } from './utils.js';
export function rehypeApplyFrontmatterExport() {
return function (tree: any, vfile: VFile) {
const astroData = safelyGetAstroData(vfile.data);
if (astroData instanceof InvalidAstroDataError)
throw new Error(
// Copied from Astro core `errors-data`
// TODO: find way to import error data from core
'[MDX] A remark or rehype plugin attempted to inject invalid frontmatter. Ensure "astro.frontmatter" is set to a valid JSON object that is not `null` or `undefined`.'
);
const { frontmatter } = astroData;
const exportNodes = [
jsToTreeNode(`export const frontmatter = ${JSON.stringify(frontmatter)};`),
];
if (frontmatter.layout) {
// NOTE(bholmesdev) 08-22-2022
// Using an async layout import (i.e. `const Layout = (await import...)`)
// Preserves the dev server import cache when globbing a large set of MDX files
// Full explanation: 'https://github.com/withastro/astro/pull/4428'
exportNodes.unshift(
jsToTreeNode(
/** @see 'vite-plugin-markdown' for layout props reference */
`import { jsx as layoutJsx } from 'astro/jsx-runtime';
export default async function ({ children }) {
const Layout = (await import(${JSON.stringify(frontmatter.layout)})).default;
const { layout, ...content } = frontmatter;
content.file = file;
content.url = url;
return layoutJsx(Layout, {
file,
url,
content,
frontmatter: content,
headings: getHeadings(),
'server:root': true,
children,
});
};`
)
);
}
tree.children = exportNodes.concat(tree.children);
};
}