Frontmatter injection for MD and MDX (#4176)

* feat: inject vfile data as exports

* feat: add vfile to renderMarkdown output

* feat: add safe astroExports parser to utils

* refactor: expose vite-plugin-utils on astro package

* feat: handle astroExports in mdx

* deps: vfile

* chore: lockfile

* test: astroExports in mdx

* refactor: merge plugin exports into forntmatter

* refactor: astroExports -> astro.frontmatter

* refactor: md astroExports -> astro.frontmatter

* feat: astro.frontmatter vite-plugin-markdown

* chore: remove unused import

* fix: inline safelyGetAstroData in MDX integration

* chore: check that frontmatter export is valid export name

* chore: error log naming

* test: mdx remark frontmatter injection

* fix: inconsistent shiki mod resolution

* fix: add new frontmatter and heading props

* test: remark vdata

* fix: spread astro.data.frontmatter

* test deps: mdast-util-to-string, reading-time

* fix: astro-md test package name

* test: md frontmatter injection

* fix: layouts

* deps: remove vite-plugin-utils export

* fix: package lock

* chore: remove dup import

* chore: changeset

* chore: add comment on safelyGetAstroData source

* deps: move mdast-util-to-string + reading-time to test fixture

* chore: move remark plugins to test fixture

* fix: override plugin frontmatter with user frontmatter

* test: md injected frontmatter overrides

* test: frontmatter injection overrides mdx

1 files changed, 40 insertions, 0 deletions

diff --git a/packages/integrations/mdx/test/mdx-frontmatter-injection.test.js b/packages/integrations/mdx/test/mdx-frontmatter-injection.test.js
new file mode 100644
index 000000000..ae1d485bb
--- /dev/null
+++ b/packages/integrations/mdx/test/mdx-frontmatter-injection.test.js
@@ -0,0 +1,40 @@
+import { expect } from 'chai';
+import { loadFixture } from '../../../astro/test/test-utils.js';
+
+const FIXTURE_ROOT = new URL('./fixtures/mdx-frontmatter-injection/', import.meta.url);
+
+describe('MDX frontmatter injection', () => {
+	let fixture;
+
+	before(async () => {
+		fixture = await loadFixture({
+			root: FIXTURE_ROOT,
+		});
+		await fixture.build();
+	});
+
+	it('remark supports custom vfile data - get title', async () => {
+		const frontmatterByPage = JSON.parse(await fixture.readFile('/glob.json'));
+		const titles = frontmatterByPage.map((frontmatter = {}) => frontmatter.title);
+		expect(titles).to.contain('Page 1');
+		expect(titles).to.contain('Page 2');
+	});
+
+	it('rehype supports custom vfile data - reading time', async () => {
+		const frontmatterByPage = JSON.parse(await fixture.readFile('/glob.json'));
+		const readingTimes = frontmatterByPage.map((frontmatter = {}) => frontmatter.injectedReadingTime);
+		expect(readingTimes.length).to.be.greaterThan(0);
+		for (let readingTime of readingTimes) {
+			expect(readingTime).to.not.be.null;
+			expect(readingTime.text).match(/^\d+ min read/);
+		}
+	});
+
+	it('overrides injected frontmatter with user frontmatter', 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');
+	});
+});