Fix: correctly transform `import.meta.env.*` in MDX (#4858)

* fix: serialize route pattern for Netlify edge

Co-authored-by: Jackie Macharia <jackiewmacharia>

* fix: escape import.meta.env in MDX compiler output

* test: env vars in mdx

* chore: changeset

* deps: estree-util-visit, @types/estree

* feat: inject import.meta.env w/ recma

* feat: pull importMetaEnv from vite + astro configs

* test: `import.meta.env` in JSX

* fix: lockfile

* chore: update changeset

* fix: remove stray stashed commit

5 files changed, 119 insertions, 0 deletions

diff --git a/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/astro.config.mjs b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/astro.config.mjs
new file mode 100644
index 000000000..df0e78193
--- /dev/null
+++ b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/astro.config.mjs
@@ -0,0 +1,9 @@
+import mdx from '@astrojs/mdx';
+
+export default {
+	site: 'https://mdx-is-neat.com/',
+	markdown: {
+		syntaxHighlight: false,
+	},
+	integrations: [mdx()],
+}
diff --git a/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/package.json b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/package.json
new file mode 100644
index 000000000..d282c887e
--- /dev/null
+++ b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@test/mdx-env-variables",
+  "dependencies": {
+    "astro": "workspace:*",
+    "@astrojs/mdx": "workspace:*"
+  }
+}
diff --git a/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/src/pages/frontmatter.json.js b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/src/pages/frontmatter.json.js
new file mode 100644
index 000000000..ce3cf81e5
--- /dev/null
+++ b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/src/pages/frontmatter.json.js
@@ -0,0 +1,7 @@
+import { frontmatter } from './vite-env-vars.mdx';
+
+export function get() {
+	return {
+		body: JSON.stringify(frontmatter),
+	}
+}
diff --git a/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/src/pages/vite-env-vars.mdx b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/src/pages/vite-env-vars.mdx
new file mode 100644
index 000000000..dae32aed2
--- /dev/null
+++ b/packages/integrations/mdx/test/fixtures/mdx-vite-env-vars/src/pages/vite-env-vars.mdx
@@ -0,0 +1,38 @@
+---
+title: Let's talk about my import.meta.env.SITE
+---
+
+export const modeWorks =
+	import.meta.env.MODE === 'production' ? 'MODE works' : 'MODE does not work!';
+
+# About my import.meta.env.SITE
+
+My `import.meta.env.SITE` is so cool, I can put env variables in code!
+
+```js
+const site = import.meta.env.SITE;
+```
+
+## But I can use import.meta.env properly too
+
+<div data-env-site>
+
+I can compute my site, for example: {new URL('/blog/cool-post', import.meta.env.SITE)}
+
+</div>
+
+<div data-env-variable-exports>
+
+I can also use `import.meta.env` in variable exports: {modeWorks}
+
+</div>
+
+I can also use vars as HTML attributes:
+
+<div
+	data-env-dump
+	data-env-prod={import.meta.env.PROD}
+	data-env-dev={import.meta.env.DEV}
+	data-env-base-url={import.meta.env.BASE_URL}
+	data-env-mode={import.meta.env.MODE}
+></div>
diff --git a/packages/integrations/mdx/test/mdx-vite-env-vars.test.js b/packages/integrations/mdx/test/mdx-vite-env-vars.test.js
new file mode 100644
index 000000000..9504b7305
--- /dev/null
+++ b/packages/integrations/mdx/test/mdx-vite-env-vars.test.js
@@ -0,0 +1,58 @@
+import { expect } from 'chai';
+import { parseHTML } from 'linkedom';
+import { loadFixture } from '../../../astro/test/test-utils.js';
+
+describe('MDX - Vite env vars', () => {
+	let fixture;
+	before(async () => {
+		fixture = await loadFixture({
+			root: new URL('./fixtures/mdx-vite-env-vars/', import.meta.url),
+		});
+		await fixture.build();
+	});
+
+	it('Avoids transforming `import.meta.env` outside JSX expressions', async () => {
+		const html = await fixture.readFile('/vite-env-vars/index.html');
+		const { document } = parseHTML(html);
+		
+		expect(document.querySelector('h1')?.innerHTML).to.contain('import.meta.env.SITE');
+		expect(document.querySelector('code')?.innerHTML).to.contain('import.meta.env.SITE');
+		expect(document.querySelector('pre')?.innerHTML).to.contain('import.meta.env.SITE');
+	});
+	it('Allows referencing `import.meta.env` in frontmatter', async () => {
+		const { title = '' } = JSON.parse(await fixture.readFile('/frontmatter.json'));
+		expect(title).to.contain('import.meta.env.SITE');
+	});
+	it('Transforms `import.meta.env` in {JSX expressions}', async () => {
+		const html = await fixture.readFile('/vite-env-vars/index.html');
+		const { document } = parseHTML(html);
+
+		expect(document.querySelector('[data-env-site]')?.innerHTML).to.contain(
+			'https://mdx-is-neat.com/blog/cool-post',
+		);
+	});
+	it('Transforms `import.meta.env` in variable exports', async () => {
+		const html = await fixture.readFile('/vite-env-vars/index.html');
+		const { document } = parseHTML(html);
+
+		expect(document.querySelector('[data-env-variable-exports]')?.innerHTML).to.contain(
+			'MODE works',
+		);
+	});
+	it('Transforms `import.meta.env` in HTML attributes', async () => {
+		const html = await fixture.readFile('/vite-env-vars/index.html');
+		const { document } = parseHTML(html);
+
+		const dataAttrDump = document.querySelector('[data-env-dump]');
+		expect(dataAttrDump).to.not.be.null; 
+
+		expect(dataAttrDump.getAttribute('data-env-prod')).to.not.be.null;
+		expect(dataAttrDump.getAttribute('data-env-dev')).to.be.null;
+		expect(dataAttrDump.getAttribute('data-env-base-url')).to.equal(
+			'/',
+		);
+		expect(dataAttrDump.getAttribute('data-env-mode')).to.equal(
+			'production',
+		);
+	});
+});