angular
diff --git a/‎packages/common/http/src/transfer_cache.ts‎
Lines changed: 5 additions & 5 deletions b/‎packages/common/http/src/transfer_cache.ts‎
Lines changed: 5 additions & 5 deletions
diff --git a/‎packages/common/http/test/transfer_cache_spec.ts‎
Lines changed: 40 additions & 1 deletion b/‎packages/common/http/test/transfer_cache_spec.ts‎
Lines changed: 40 additions & 1 deletion
@@ -374,17 +374,17 @@ function getFilteredHeaders(
 }
 
 function sortAndConcatParams(params: HttpParams | URLSearchParams): string {
-  return [...params.keys()]
-    .sort()
-    .map((k) => `${k}=${params.getAll(k)}`)
-    .join('&');
+  const searchParams = new URLSearchParams(
+    params instanceof URLSearchParams ? params : params.toString(),
+  );
+  searchParams.sort();
+  return searchParams.toString();
 }
 
 function makeCacheKey(
   request: HttpRequest<any>,
   mappedRequestUrl: string,
 ): StateKey<TransferHttpResponse> {
-  // make the params encoded same as a url so it's easy to identify
   const {params, method, responseType} = request;
   const encodedParams = sortAndConcatParams(params);
 
 
@@ -19,7 +19,14 @@ import {TestBed} from '@angular/core/testing';
 import {useAutoTick, timeout, withBody} from '@angular/private/testing';
 import {BehaviorSubject, Observable, of} from 'rxjs';
 
-import {HttpClient, HttpHeaders, HttpRequest, HttpResponse, provideHttpClient} from '../public_api';
+import {
+  HttpClient,
+  HttpHeaders,
+  HttpParams,
+  HttpRequest,
+  HttpResponse,
+  provideHttpClient,
+} from '../public_api';
 import {
   BODY,
   CACHE_OPTIONS,
@@ -458,6 +465,38 @@ describe('TransferCache', () => {
       );
     });
 
+    it('should differentiate repeated parameters from scalar comma parameters', () => {
+      let scalarResponse!: string;
+      TestBed.inject(HttpClient)
+        .get('/test-params', {params: new HttpParams().set('role', 'user,admin')})
+        .subscribe((response) => (scalarResponse = response as string));
+      TestBed.inject(HttpTestingController)
+        .expectOne('/test-params?role=user,admin')
+        .flush('scalar');
+
+      let repeatedResponse!: string;
+      TestBed.inject(HttpClient)
+        .get('/test-params', {
+          params: new HttpParams().append('role', 'user').append('role', 'admin'),
+        })
+        .subscribe((response) => (repeatedResponse = response as string));
+      TestBed.inject(HttpTestingController)
+        .expectOne('/test-params?role=user&role=admin')
+        .flush('repeated');
+
+      let repeatedCachedResponse!: string;
+      TestBed.inject(HttpClient)
+        .get('/test-params', {
+          params: new HttpParams().append('role', 'user').append('role', 'admin'),
+        })
+        .subscribe((response) => (repeatedCachedResponse = response as string));
+      TestBed.inject(HttpTestingController).expectNone('/test-params?role=user&role=admin');
+
+      expect(scalarResponse).toBe('scalar');
+      expect(repeatedResponse).toBe('repeated');
+      expect(repeatedCachedResponse).toBe('repeated');
+    });
+
     it('should skip cache when specified', () => {
       makeRequestAndExpectOne('/test-1?foo=1', 'foo', {transferCache: false});
       // The previous request wasn't cached so this one can't use the cache