fix(@angular/build): support HTTP HEAD requests for virtual output files

packages/angular/build/src/tools/vite/middlewares/assets-middleware.ts

@@ -63,6 +63,12 @@ export function createAngularAssetsMiddleware(
       return;
     }
 
+    // Support HTTP HEAD requests for the virtual output files from the Angular build
+    if (req.method === 'HEAD' && outputFiles.get(pathname)?.servable) {
+      // While a GET will also generate content, the rest of the response is equivalent
+      req.method = 'GET';
+    }
+
     // Resource files are handled directly.
     // Global stylesheets (CSS files) are currently considered resources to workaround
     // dev server sourcemap issues with stylesheets.

tests/legacy-cli/e2e/tests/commands/serve/head-request.ts

@@ -0,0 +1,25 @@
+import { ngServe } from '../../../utils/project';
+
+export default async function () {
+  const port = await ngServe();
+  // HTML
+  await checkHeadForUrl(`http://localhost:${port}/index.html`);
+  // Generated JS
+  await checkHeadForUrl(`http://localhost:${port}/main.js`);
+  // Generated CSS
+  await checkHeadForUrl(`http://localhost:${port}/styles.css`);
+  // Configured asset
+  await checkHeadForUrl(`http://localhost:${port}/favicon.ico`);
+}
+
+async function checkHeadForUrl(url: string): Promise<void> {
+  const result = await fetch(url, { method: 'HEAD' });
+  const content = await result.blob();
+
+  if (content.size !== 0) {
+    throw new Error(`Expected "size" to be "0" but got "${content.size}".`);
+  }
+  if (result.status !== 200) {
+    throw new Error(`Expected "status" to be "200" but got "${result.status}".`);
+  }
+}

tests/legacy-cli/e2e/tests/i18n/extract-ivy.ts

@@ -27,6 +27,9 @@ export default async function () {
   `,
   );
 
+  // Ensure localize package is not present initially
+  await uninstallPackage('@angular/localize');
+
   // Should fail if `@angular/localize` is missing
   const { message: message1 } = await expectToFail(() => ng('extract-i18n'));
   if (!message1.includes(`i18n extraction requires the '@angular/localize' package.`)) {