@angular/service-worker: Request Credential & Cache Policy Stripping

@@ -501,12 +501,16 @@ export abstract class AssetGroup {
    * Create a new `Request` based on the specified URL and `RequestInit` options, preserving only
    * metadata that are known to be safe.
    *
-   * Currently, headers, redirect policy, and an explicit `credentials: 'omit'` are preserved.
+   * Currently, headers, redirect policy, an explicit `credentials: 'omit'`, and the HTTP cache
+   * mode are preserved.
    *
    * NOTE:
    *   `credentials: 'same-origin'` and `credentials: 'include'` are intentionally not preserved.
    *   Forwarding `'include'` could leak cookies to cross-origin asset hosts, and forwarding
    *   `'same-origin'` matches the default `fetch()` behavior so there is nothing to preserve.
+   *   Requests with `cache: 'only-if-cached'` and `mode !== 'same-origin'` are short-circuited
+   *   earlier in `Driver.onFetch()` (they are a known Chrome DevTools quirk), so no special
+   *   handling for that combination is needed here.
    * TODO(gkalpak):
    *   Investigate preserving more metadata. See, also, discussion on preserving `mode`:
    *   https://github.com/angular/angular/issues/41931#issuecomment-1227601347.
@@ -521,6 +525,10 @@ export abstract class AssetGroup {
       init.credentials = 'omit';
     }
 
+    if (options.cache !== undefined) {
+      init.cache = options.cache;
+    }
+
     return this.adapter.newRequest(url, init);
   }
 

@@ -1667,6 +1667,18 @@ import {envIsSupported} from '../testing/utils';
         expect(bazReq.credentials).toBe('omit');
       });
 
+      it(`passes 'cache' through to the server`, async () => {
+        // Request a lazy-cached asset (so that it is fetched from the network) and provide an
+        // explicit HTTP cache mode.
+        const reqInit = {cache: 'no-store'};
+        expect(await makeRequest(scope, '/baz.txt', undefined, reqInit)).toBe('this is baz');
+
+        // Verify that the explicit `cache` value was preserved (instead of being replaced by the
+        // default `'default'`).
+        const [bazReq] = server.getRequestsFor('/baz.txt');
+        expect(bazReq.cache).toBe('no-store');
+      });
+
       describe('for redirect requests', () => {
         it('passes headers through to the server', async () => {
           // Request a redirected, lazy-cached asset (so that it is fetched from the network) and
@@ -1721,6 +1733,20 @@ import {envIsSupported} from '../testing/utils';
           const [redirectReq] = server.getRequestsFor('/lazy/redirect-target.txt');
           expect(redirectReq.credentials).toBe('omit');
         });
+
+        it(`passes 'cache' through to the server`, async () => {
+          // Request a redirected, lazy-cached asset (so that it is fetched from the network) and
+          // provide an explicit HTTP cache mode.
+          const reqInit = {cache: 'no-store'};
+          expect(await makeRequest(scope, '/lazy/redirected.txt', undefined, reqInit)).toBe(
+            'this was a redirect too',
+          );
+
+          // Verify that the explicit `cache` value was preserved across the redirect
+          // reconstruction (instead of being replaced by the default `'default'`).
+          const [redirectReq] = server.getRequestsFor('/lazy/redirect-target.txt');
+          expect(redirectReq.cache).toBe('no-store');
+        });
       });
     });
 

@@ -167,6 +167,7 @@ export class MockRequest extends MockBody implements Request {
     }
     return new MockRequest(this.url, {
       body: this._body,
+      cache: this.cache,
       mode: this.mode,
       credentials: this.credentials,
       headers: this.headers,