fix(common): support equality function in httpResource (#60026)

The `equal` option was not passed to the underlying resource.

PR Close #60026

packages/common/http/src/resource.ts

@@ -19,6 +19,7 @@ import {
   Resource,
   WritableSignal,
   ResourceStreamItem,
+  type ValueEqualityFn,
 } from '@angular/core';
 import {Subscription} from 'rxjs';
 
@@ -240,6 +241,7 @@ function makeHttpResourceFn<TRaw>(responseType: 'arraybuffer' | 'blob' | 'json'
       () => normalizeRequest(request, responseType),
       options?.defaultValue,
       options?.parse as (value: unknown) => TResult,
+      options?.equal as ValueEqualityFn<unknown>,
     ) as HttpResourceRef<TResult>;
   };
 }
@@ -313,6 +315,7 @@ class HttpResourceImpl<T>
     request: () => HttpRequest<T> | undefined,
     defaultValue: T,
     parse?: (value: unknown) => T,
+    equal?: ValueEqualityFn<unknown>,
   ) {
     super(
       request,
@@ -364,7 +367,7 @@ class HttpResourceImpl<T>
         return promise;
       },
       defaultValue,
-      undefined,
+      equal,
       injector,
     );
     this.client = injector.get(HttpClient);

packages/common/http/test/resource_spec.ts

@@ -165,6 +165,23 @@ describe('httpResource', () => {
     expect(res.value()).toEqual('[1,2,3]');
   });
 
+  it('should allow defining an equality function', async () => {
+    const backend = TestBed.inject(HttpTestingController);
+    const res = httpResource<number>('/data', {
+      injector: TestBed.inject(Injector),
+      equal: (_a, _b) => true,
+    });
+    TestBed.flushEffects();
+    const req = backend.expectOne('/data');
+    req.flush(1);
+
+    await TestBed.inject(ApplicationRef).whenStable();
+    expect(res.value()).toEqual(1);
+
+    res.value.set(5);
+    expect(res.value()).toBe(1); // equality blocked writes
+  });
+
   it('should support text responses', async () => {
     const backend = TestBed.inject(HttpTestingController);
     const res = httpResource.text(