From 104c18aa67290db8f11faa91d9a009871ea6e462 Mon Sep 17 00:00:00 2001
From: bholmesdev <hey@bholmes.dev>
Date: Mon, 22 Aug 2022 16:39:13 -0400
Subject: [PATCH 1/3] fix: move layout to async import

---
 packages/integrations/mdx/src/astro-data-utils.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/integrations/mdx/src/astro-data-utils.ts b/packages/integrations/mdx/src/astro-data-utils.ts
index f3d04e431617..cc1dc3f4c08f 100644
--- a/packages/integrations/mdx/src/astro-data-utils.ts
+++ b/packages/integrations/mdx/src/astro-data-utils.ts
@@ -24,9 +24,9 @@ export function rehypeApplyFrontmatterExport(pageFrontmatter: Record<string, any
 				jsToTreeNode(
 					/** @see 'vite-plugin-markdown' for layout props reference */
 					`import { jsx as layoutJsx } from 'astro/jsx-runtime';
-				import Layout from ${JSON.stringify(frontmatter.layout)};
 				
-				export default function ({ children }) {
+				export default async function ({ children }) {
+					const Layout = (await import(${JSON.stringify(frontmatter.layout)})).default;
 					const { layout, ...content } = frontmatter;
 					content.file = file;
 					content.url = url;

From 16d274276c62ac2adbc4b980a69441a5a95966bc Mon Sep 17 00:00:00 2001
From: bholmesdev <hey@bholmes.dev>
Date: Mon, 22 Aug 2022 17:11:59 -0400
Subject: [PATCH 2/3] chore: changeset

---
 .changeset/kind-onions-reply.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/kind-onions-reply.md

diff --git a/.changeset/kind-onions-reply.md b/.changeset/kind-onions-reply.md
new file mode 100644
index 000000000000..8092d377292c
--- /dev/null
+++ b/.changeset/kind-onions-reply.md
@@ -0,0 +1,5 @@
+---
+'@astrojs/mdx': patch
+---
+
+Fix dev server reload performance when globbing from an MDX layout

From 8fc7469302d3371de44317016ad9f71d66d2836d Mon Sep 17 00:00:00 2001
From: bholmesdev <hey@bholmes.dev>
Date: Mon, 22 Aug 2022 17:34:25 -0400
Subject: [PATCH 3/3] docs: clarify async import

---
 packages/integrations/mdx/src/astro-data-utils.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/integrations/mdx/src/astro-data-utils.ts b/packages/integrations/mdx/src/astro-data-utils.ts
index cc1dc3f4c08f..6bd2186e27b5 100644
--- a/packages/integrations/mdx/src/astro-data-utils.ts
+++ b/packages/integrations/mdx/src/astro-data-utils.ts
@@ -20,6 +20,10 @@ export function rehypeApplyFrontmatterExport(pageFrontmatter: Record<string, any
 			jsToTreeNode(`export const ${EXPORT_NAME} = ${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 */