fix(@angular/ssr): redirect to locale pathname instead of full URL

packages/angular/ssr/src/app-engine.ts

@@ -97,8 +97,8 @@ export class AngularAppEngine {
     const { basePath, supportedLocales } = this.manifest;
 
     // If the request is not for the base path, it's not our responsibility to handle it.
-    const url = new URL(request.url);
-    if (url.pathname !== basePath) {
+    const { pathname } = new URL(request.url);
+    if (pathname !== basePath) {
       return null;
     }
 
@@ -112,12 +112,10 @@ export class AngularAppEngine {
     if (preferredLocale) {
       const subPath = supportedLocales[preferredLocale];
       if (subPath !== undefined) {
-        url.pathname = joinUrlParts(url.pathname, subPath);
-
         return new Response(null, {
           status: 302, // Use a 302 redirect as language preference may change.
           headers: {
-            'Location': url.toString(),
+            'Location': joinUrlParts(pathname, subPath),
             'Vary': 'Accept-Language',
           },
         });

packages/angular/ssr/test/app-engine_spec.ts

@@ -157,12 +157,12 @@ describe('AngularAppEngine', () => {
       });
 
       it('should redirect to the highest priority locale when the URL is "/"', async () => {
-        const request = new Request('https://example.com/', {
+        const request = new Request('https://example.com', {
           headers: { 'Accept-Language': 'fr-CH, fr;q=0.9, it;q=0.8, en;q=0.7, *;q=0.5' },
         });
         const response = await appEngine.handle(request);
         expect(response?.status).toBe(302);
-        expect(response?.headers.get('Location')).toBe('https://example.com/it');
+        expect(response?.headers.get('Location')).toBe('/it');
         expect(response?.headers.get('Vary')).toBe('Accept-Language');
       });