fix(@angular/build): quote weak ETags of assets served by the dev server

Extensionless, JavaScript, TypeScript and stylesheet assets served by the dev server and the
Vitest browser runner sent an unquoted weak ETag such as `W/25a71cd345af2de4`. RFC 9110 requires
the entity tag to be quoted (`W/"25a71cd345af2de4"`), which is how the other ETags in the same
middleware are already formatted.

Author: MeAkib

packages/angular/build/src/builders/dev-server/tests/behavior/build-assets_spec.ts

@@ -41,6 +41,23 @@ describeServeBuilder(executeDevServer, DEV_SERVER_BUILDER_INFO, (harness, setupT
       expect(await response?.text()).toContain(javascriptFileContent);
     });
 
+    it('serves a project extensionless asset with a valid weak ETag', async () => {
+      await harness.writeFile('src/extensionless', javascriptFileContent);
+
+      setupTarget(harness, {
+        assets: ['src/extensionless'],
+      });
+
+      harness.useTarget('serve', {
+        ...BASE_OPTIONS,
+      });
+
+      const { result, response } = await executeOnceAndFetch(harness, 'extensionless');
+
+      expect(result?.success).toBeTrue();
+      expect(response?.headers.get('ETag')).toMatch(/^W\/"[^"]+"$/);
+    });
+
     it('serves a project JavaScript asset unmodified', async () => {
       await harness.writeFile('src/extra.js', javascriptFileContent);
 

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

@@ -50,7 +50,7 @@ export function createAngularAssetsMiddleware(
       // This is a workaround to serve extensionless, CSS, JS and TS files without Vite transformations.
       if (!extension || JS_TS_REGEXP.test(extension) || CSS_PREPROCESSOR_REGEXP.test(extension)) {
         const contents = readFileSync(asset.source);
-        const etag = `W/${calculateHash(contents)}`;
+        const etag = `W/"${calculateHash(contents)}"`;
         if (checkAndHandleEtag(req, res, etag)) {
           return;
         }
@@ -238,7 +238,7 @@ export function createBuildAssetsMiddleware(
         const contents =
           outputFile.origin === 'memory' ? outputFile.contents : readHandler(outputFile.source);
 
-        const etag = `W/${calculateHash(contents)}`;
+        const etag = `W/"${calculateHash(contents)}"`;
         if (checkAndHandleEtag(req, res, etag)) {
           return;
         }