Allow AlpineJS syntax extensions in Markdown (#3554)

* Allow AlpineJS syntax extensions in Markdown

* Remove unwanted MDX ESM import/export support

.changeset/swift-rocks-refuse.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/markdown-remark': patch
+---
+
+Allow AlpineJS syntax extensions in Markdown

packages/markdown/remark/package.json

@@ -24,14 +24,18 @@
     "test": "mocha --exit --timeout 20000"
   },
   "dependencies": {
+    "@astrojs/micromark-extension-mdx-jsx": "^1.0.3",
     "@astrojs/prism": "^0.4.1",
+    "acorn": "^8.7.1",
+    "acorn-jsx": "^5.3.2",
     "assert": "^2.0.0",
     "github-slugger": "^1.4.0",
     "mdast-util-mdx-expression": "^1.2.0",
     "mdast-util-mdx-jsx": "^1.2.0",
     "mdast-util-to-string": "^3.1.0",
-    "micromark-extension-mdx-jsx": "^1.0.3",
-    "micromark-extension-mdxjs": "^1.0.0",
+    "micromark-extension-mdx-expression": "^1.0.3",
+    "micromark-extension-mdx-md": "^1.0.0",
+    "micromark-util-combine-extensions": "^1.0.0",
     "prismjs": "^1.28.0",
     "rehype-raw": "^6.1.1",
     "rehype-stringify": "^9.0.3",
@@ -55,6 +59,7 @@
     "@types/unist": "^2.0.6",
     "astro-scripts": "workspace:*",
     "chai": "^4.3.6",
+    "micromark-util-types": "^1.0.2",
     "mocha": "^9.2.2"
   }
 }

packages/markdown/remark/src/mdxjs.ts

@@ -0,0 +1,31 @@
+// Note: The code in this file is based on `micromark-extension-mdxjs`
+// and was adapted to use our fork `@astrojs/micromark-extension-mdx-jsx`
+// instead of `micromark-extension-mdx-jsx` to allow some extended syntax.
+// See `@astrojs/micromark-extension-mdx-jsx` on NPM for more details.
+// Also, support for ESM imports & exports in Markdown content was removed.
+
+import { Parser } from 'acorn';
+import acornJsx from 'acorn-jsx';
+import { combineExtensions } from 'micromark-util-combine-extensions';
+import { mdxExpression } from 'micromark-extension-mdx-expression';
+import { mdxJsx } from '@astrojs/micromark-extension-mdx-jsx';
+import { mdxMd } from 'micromark-extension-mdx-md';
+import type { Options } from 'micromark-extension-mdx-expression';
+import type { Extension } from 'micromark-util-types';
+
+export function mdxjs(options: Options): Extension {
+	const settings: any = Object.assign(
+		{
+			acorn: Parser.extend(acornJsx()),
+			acornOptions: { ecmaVersion: 2020, sourceType: 'module' },
+			addResult: true
+		},
+		options
+	);
+
+	return combineExtensions([
+		mdxExpression(settings),
+		mdxJsx(settings),
+		mdxMd
+	]);
+}

packages/markdown/remark/src/remark-mdxish.ts

@@ -1,6 +1,6 @@
 import type * as fromMarkdown from 'mdast-util-from-markdown';
 import type { Tag } from 'mdast-util-mdx-jsx';
-import { mdxjs } from 'micromark-extension-mdxjs';
+import { mdxjs } from './mdxjs.js';
 import { mdxFromMarkdown, mdxToMarkdown } from './mdast-util-mdxish.js';
 
 export default function remarkMdxish(this: any, options = {}) {

packages/markdown/remark/test/strictness.test.js

@@ -15,4 +15,126 @@ describe('strictness', () => {
 					`<img src="hi.jpg" /></p>`
 			);
 	});
+
+	it('should allow attribute names starting with ":" after element names', async () => {
+		const { code } = await renderMarkdown(
+			`<div :class="open ? '' : 'hidden'">Test</div>`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<div :class="open ? '' : 'hidden'">Test</div>`);
+	});
+
+	it('should allow attribute names starting with ":" after local element names', async () => {
+		const { code } = await renderMarkdown(
+			`<div.abc :class="open ? '' : 'hidden'">x</div.abc>`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<div.abc :class="open ? '' : 'hidden'">x</div.abc>`);
+	});
+
+	it('should allow attribute names starting with ":" after attribute names', async () => {
+		const { code } = await renderMarkdown(
+			`<input type="text" disabled :placeholder="hi">`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<input type="text" disabled :placeholder="hi" />`);
+	});
+
+	it('should allow attribute names starting with ":" after local attribute names', async () => {
+		const { code } = await renderMarkdown(
+			`<input type="text" x-test:disabled :placeholder="hi">`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<input type="text" x-test:disabled :placeholder="hi" />`);
+	});
+
+	it('should allow attribute names starting with ":" after attribute values', async () => {
+		const { code } = await renderMarkdown(
+			`<input type="text" :placeholder="placeholder">`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<input type="text" :placeholder="placeholder" />`);
+	});
+
+	it('should allow attribute names starting with "@" after element names', async () => {
+		const { code } = await renderMarkdown(
+			`<button @click="handleClick">Test</button>`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<button @click="handleClick">Test</button>`);
+	});
+
+	it('should allow attribute names starting with "@" after local element names', async () => {
+		const { code } = await renderMarkdown(
+			`<button.local @click="handleClick">Test</button.local>`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<button.local @click="handleClick">Test</button.local>`);
+	});
+
+	it('should allow attribute names starting with "@" after attribute names', async () => {
+		const { code } = await renderMarkdown(
+			`<button disabled @click="handleClick">Test</button>`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<button disabled @click="handleClick">Test</button>`);
+	});
+
+	it('should allow attribute names starting with "@" after local attribute names', async () => {
+		const { code } = await renderMarkdown(
+			`<button x-test:disabled @click="handleClick">Test</button>`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<button x-test:disabled @click="handleClick">Test</button>`);
+	});
+
+	it('should allow attribute names starting with "@" after attribute values', async () => {
+		const { code } = await renderMarkdown(
+			`<button type="submit" @click="handleClick">Test</button>`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<button type="submit" @click="handleClick">Test</button>`);
+	});
+
+	it('should allow attribute names containing dots', async () => {
+		const { code } = await renderMarkdown(
+			`<input x-on:input.debounce.500ms="fetchResults">`,
+			{}
+		);
+
+		chai
+			.expect(code.trim())
+			.to.equal(`<input x-on:input.debounce.500ms="fetchResults" />`);
+	});
+
 });