fix(unplugin): transform .astro files that arrive already compiled

packages/@stylexjs/unplugin/__tests__/unplugin.test.js

@@ -29,6 +29,46 @@ describe('@stylexjs/unplugin', () => {
     expect(result).toBeNull();
   });
 
+  test('includes .astro files', () => {
+    const plugin = unplugin.raw({});
+    expect(plugin.transformInclude('/virtual/page.astro')).toBe(true);
+    expect(
+      plugin.transformInclude('/virtual/page.astro?astro&type=script'),
+    ).toBe(true);
+  });
+
+  test('compiles StyleX in .astro modules', async () => {
+    const plugin = unplugin.rollup({
+      runtimeInjection: false,
+      devPersistToDisk: false,
+      dev: false,
+    });
+    if (typeof plugin.buildStart === 'function') {
+      plugin.buildStart();
+    }
+    // Astro hands bundler plugins the compiled module, not the `---` source
+    const source = `
+      import * as stylex from '@stylexjs/stylex';
+      const styles = stylex.create({ hero: { color: 'red' } });
+      export default styles;
+    `;
+    const result = await plugin.transform(source, '/virtual/page.astro');
+    expect(result).not.toBeNull();
+    expect(result.code).not.toContain('stylex.create');
+
+    const tempDir = fs.mkdtempSync(
+      path.join(os.tmpdir(), 'stylex-unplugin-test-'),
+    );
+    try {
+      await plugin.writeBundle({ dir: tempDir }, {});
+      const cssPath = path.join(tempDir, 'assets', 'stylex.css');
+      expect(fs.existsSync(cssPath)).toBe(true);
+      expect(fs.readFileSync(cssPath, 'utf8')).toContain('color: red;');
+    } finally {
+      fs.rmSync(tempDir, { recursive: true, force: true });
+    }
+  });
+
   test('still transforms built-in imports when a custom importSource is set', async () => {
     const plugin = unplugin.raw({ importSources: ['custom-stylex'] });
     if (typeof plugin.buildStart === 'function') {

packages/@stylexjs/unplugin/src/core.js

@@ -225,6 +225,13 @@ function discoverStylexPackages({
 
 const JS_LIKE_RE = /\.[cm]?[jt]sx?(\?|$)/;
 const SVELTE_LIKE_RE = /\.svelte(\?|$)/;
+const ASTRO_LIKE_RE = /\.astro(\?|$)/;
+
+function isTransformableId(id) {
+  return (
+    JS_LIKE_RE.test(id) || SVELTE_LIKE_RE.test(id) || ASTRO_LIKE_RE.test(id)
+  );
+}
 
 export const unpluginFactory = (userOptions = {}, metaOptions) => {
   // framework :: 'rollup' | 'vite' | 'rolldown' | 'farm' | 'unloader'
@@ -423,13 +430,13 @@ export const unpluginFactory = (userOptions = {}, metaOptions) => {
     },
 
     transformInclude(id) {
-      return JS_LIKE_RE.test(id) || SVELTE_LIKE_RE.test(id);
+      return isTransformableId(id);
     },
 
     // Core code transform
     async transform(code, id) {
       // Only handle JS-like files; avoid parsing CSS/JSON/etc
-      if (!JS_LIKE_RE.test(id) && !SVELTE_LIKE_RE.test(id)) return null;
+      if (!isTransformableId(id)) return null;
       if (!shouldHandle(code)) return null;
 
       // Extract the pure filename by removing everything after '?' (e.g., handling Vite's '?v=' cache busting).