fix(vite-plugin-angular): preserve import.meta during Vitest downleveling

Author: benjavicente

packages/vite-plugin-angular/src/lib/angular-vitest-plugin-esbuild.spec.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it, vi } from 'vitest';
+import { angularVitestPlugin } from './angular-vitest-plugin';
+
+// Exercise the Vite 6/7 fallback while the workspace itself uses Vite 8.
+vi.mock(import('./utils/rolldown.js'), () => ({
+  getJsTransformConfigKey: () => 'esbuild',
+  isRolldown: () => false,
+}));
+
+const transform = (code: string, id: string) => {
+  const hook = angularVitestPlugin().transform as {
+    handler: (code: string, id: string) => Promise<{ code: string }>;
+  };
+  return hook.handler(code, id);
+};
+
+describe('angularVitestPlugin esbuild downleveling', () => {
+  it('preserves HMR access in generated CDK CSS modules', async () => {
+    const { code } = await transform(
+      'export const id = "/node_modules/@angular/cdk/overlay-prebuilt.css"; import.meta.hot.accept();',
+      '/node_modules/@angular/cdk/overlay-prebuilt.css',
+    );
+
+    expect(code).toContain('import.meta.hot.accept()');
+  });
+
+  it('preserves module metadata while downleveling async functions', async () => {
+    const { code } = await transform(
+      'export const url = import.meta.url; export async function example() { return await Promise.resolve(42); }',
+      '/node_modules/@angular/core/fesm2022/core.mjs',
+    );
+    const moduleUrl = `data:text/javascript;base64,${Buffer.from(code).toString('base64')}`;
+    const result = await import(moduleUrl);
+
+    expect(result.url).toBe(moduleUrl);
+    expect(await result.example()).toBe(42);
+    expect(code).not.toMatch(/\basync\s+function\b/);
+  });
+});

packages/vite-plugin-angular/src/lib/angular-vitest-plugin.ts

@@ -79,6 +79,7 @@ export function angularVitestPlugin(): Plugin {
             loader: 'js',
             format: 'esm',
             target: 'es2016',
+            supported: { 'import-meta': true },
             sourcemap: true,
             sourcefile: id,
           });