Improve MDX rendering performance (#8533)

3 files changed, 8 insertions, 7 deletions

diff --git a/packages/markdown/remark/src/frontmatter-injection.ts b/packages/markdown/remark/src/frontmatter-injection.ts
index 4f5118ece..4828873fd 100644
--- a/packages/markdown/remark/src/frontmatter-injection.ts
+++ b/packages/markdown/remark/src/frontmatter-injection.ts
@@ -27,12 +27,14 @@ export function safelyGetAstroData(vfileData: Data): MarkdownAstroData | Invalid
 	return astro;
 }
 
-export function setAstroData(vfileData: Data, astroData: MarkdownAstroData) {
-	vfileData.astro = astroData;
+export function setVfileFrontmatter(vfile: VFile, frontmatter: Record<string, any>) {
+	vfile.data ??= {};
+	vfile.data.astro ??= {};
+	(vfile.data.astro as any).frontmatter = frontmatter;
 }
 
 /**
- * @deprecated Use `setAstroData` instead
+ * @deprecated Use `setVfileFrontmatter` instead
  */
 export function toRemarkInitializeAstroData({
 	userFrontmatter,
diff --git a/packages/markdown/remark/src/index.ts b/packages/markdown/remark/src/index.ts
index 41d08ec9a..89c9ca8bd 100644
--- a/packages/markdown/remark/src/index.ts
+++ b/packages/markdown/remark/src/index.ts
@@ -9,7 +9,7 @@ import type {
 import {
 	InvalidAstroDataError,
 	safelyGetAstroData,
-	setAstroData,
+	setVfileFrontmatter,
 } from './frontmatter-injection.js';
 import { loadPlugins } from './load-plugins.js';
 import { rehypeHeadingIds } from './rehype-collect-headings.js';
@@ -27,7 +27,7 @@ import { unified } from 'unified';
 import { VFile } from 'vfile';
 import { rehypeImages } from './rehype-images.js';
 
-export { InvalidAstroDataError } from './frontmatter-injection.js';
+export { InvalidAstroDataError, setVfileFrontmatter } from './frontmatter-injection.js';
 export { rehypeHeadingIds } from './rehype-collect-headings.js';
 export { remarkCollectImages } from './remark-collect-images.js';
 export { remarkPrism } from './remark-prism.js';
@@ -125,7 +125,7 @@ export async function createMarkdownProcessor(
 	return {
 		async render(content, renderOpts) {
 			const vfile = new VFile({ value: content, path: renderOpts?.fileURL });
-			setAstroData(vfile.data, { frontmatter: renderOpts?.frontmatter ?? {} });
+			setVfileFrontmatter(vfile, renderOpts?.frontmatter ?? {});
 
 			const result: MarkdownVFile = await parser.process(vfile).catch((err) => {
 				// Ensure that the error message contains the input filename
diff --git a/packages/markdown/remark/src/internal.ts b/packages/markdown/remark/src/internal.ts
index a0f344a3a..0ab7e34bb 100644
--- a/packages/markdown/remark/src/internal.ts
+++ b/packages/markdown/remark/src/internal.ts
@@ -1,6 +1,5 @@
 export {
 	InvalidAstroDataError,
 	safelyGetAstroData,
-	setAstroData,
 	toRemarkInitializeAstroData,
 } from './frontmatter-injection.js';