Change frontmatter injection ordering (#5687)

* feat: make user frontmatter accessible in md

* test: new frontmatter injection

* refactor: move injection utils to remark pkg

* fix: add dist/internal to remark exports

* feat: update frontmater injection in mdx

* tests: new mdx injection

* chore: changeset

* chore: simplify frontmatter destructuring

* fix: remove old _internal references

* refactor: injectedFrontmatter -> remarkPluginFrontmatter

* docs: add content collections change

* chore: changeset heading levels

6 files changed, 15 insertions, 16 deletions

diff --git a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/astro.config.mjs b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/astro.config.mjs
index fc15686c2..5335fac87 100644
--- a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/astro.config.mjs
+++ b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/astro.config.mjs
@@ -1,12 +1,12 @@
 import { defineConfig } from 'astro/config';
 import mdx from '@astrojs/mdx';
-import { rehypeReadingTime, remarkTitle } from './src/markdown-plugins.mjs';
+import { rehypeReadingTime, remarkDescription, remarkTitle } from './src/markdown-plugins.mjs';
 
 // https://astro.build/config
 export default defineConfig({
   site: 'https://astro.build/',
 	integrations: [mdx({
-		remarkPlugins: [remarkTitle],
+		remarkPlugins: [remarkTitle, remarkDescription],
 		rehypePlugins: [rehypeReadingTime],
 	})],
 });
diff --git a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/markdown-plugins.mjs b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/markdown-plugins.mjs
index c0d5f7b2e..35b415787 100644
--- a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/markdown-plugins.mjs
+++ b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/markdown-plugins.mjs
@@ -18,3 +18,10 @@ export function remarkTitle() {
 		});
 	};
 }
+
+export function remarkDescription() {
+	return function (tree, vfile) {
+		const { frontmatter } = vfile.data.astro;
+		frontmatter.description = `Processed by remarkDescription plugin: ${frontmatter.description}`
+	};
+}
diff --git a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-1.mdx b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-1.mdx
index 1092099f0..0d96d95b9 100644
--- a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-1.mdx
+++ b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-1.mdx
@@ -1,5 +1,6 @@
 ---
 layout: '../layouts/Base.astro'
+description: Page 1 description
 ---
 
 # Page 1
diff --git a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-2.mdx b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-2.mdx
index c82eb97c2..fe6a8286b 100644
--- a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-2.mdx
+++ b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/page-2.mdx
@@ -1,5 +1,6 @@
 ---
 layout: '../layouts/Base.astro'
+description: Page 2 description
 ---
 
 # Page 2
diff --git a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/with-overrides.mdx b/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/with-overrides.mdx
deleted file mode 100644
index 4e11c1c37..000000000
--- a/packages/integrations/mdx/test/fixtures/mdx-frontmatter-injection/src/pages/with-overrides.mdx
+++ /dev/null
@@ -1,7 +0,0 @@
----
-title: 'Overridden title'
-injectedReadingTime: 
-  text: '1000 min read'
----
-
-# Working!
diff --git a/packages/integrations/mdx/test/mdx-frontmatter-injection.test.js b/packages/integrations/mdx/test/mdx-frontmatter-injection.test.js
index 780f7252c..8f598b78e 100644
--- a/packages/integrations/mdx/test/mdx-frontmatter-injection.test.js
+++ b/packages/integrations/mdx/test/mdx-frontmatter-injection.test.js
@@ -33,14 +33,11 @@ describe('MDX frontmatter injection', () => {
 		}
 	});
 
-	it('overrides injected frontmatter with user frontmatter', async () => {
+	it('allow user frontmatter mutation', async () => {
 		const frontmatterByPage = JSON.parse(await fixture.readFile('/glob.json'));
-		const readingTimes = frontmatterByPage.map(
-			(frontmatter = {}) => frontmatter.injectedReadingTime?.text
-		);
-		const titles = frontmatterByPage.map((frontmatter = {}) => frontmatter.title);
-		expect(titles).to.contain('Overridden title');
-		expect(readingTimes).to.contain('1000 min read');
+		const descriptions = frontmatterByPage.map((frontmatter = {}) => frontmatter.description);
+		expect(descriptions).to.contain('Processed by remarkDescription plugin: Page 1 description');
+		expect(descriptions).to.contain('Processed by remarkDescription plugin: Page 2 description');
 	});
 
 	it('passes injected frontmatter to layouts', async () => {