feat(app-state): spreadObjectStore$() handles null and undefined

projects/app-state/src/lib/utils/spread-array-store.spec.ts

@@ -78,7 +78,7 @@ describe('spreadArrayStore$()', () => {
     arrayStore.set([1]);
     expect(emitted.length).toBe(1);
 
-    arrayStore.delete();
+    arrayStore.set(null);
     expect(emitted.length).toBe(0);
   });
 });

projects/app-state/src/lib/utils/spread-object-store.spec.ts

@@ -73,4 +73,22 @@ describe('spreadObjectStore$()', () => {
     store.set({ b: 6 });
     expect(lastEmit![0]).toBe(previousEmit![1]);
   });
+
+  it('treats null and undefined as empty objects', () => {
+    interface State {
+      object?: Record<string, number> | null;
+    }
+    const objectStore = new RootStore<State>({})('object');
+    let emitted!: Array<Store<number>>;
+    spreadObjectStore$(objectStore).subscribe((stores) => {
+      emitted = stores;
+    });
+    expect(emitted.length).toBe(0);
+
+    objectStore.set({ a: 1 });
+    expect(emitted.length).toBe(1);
+
+    objectStore.set(null);
+    expect(emitted.length).toBe(0);
+  });
 });

projects/app-state/src/lib/utils/spread-object-store.ts

@@ -32,7 +32,7 @@ import { Store } from '../index';
  * ```
  */
 export function spreadObjectStore$<T extends object>(
-  source: Store<T>,
+  source: Store<T | null | undefined>,
 ): Observable<Array<Store<T[keyof T]>>> {
   let lastKeySet: Set<string | keyof T> | undefined;
   return source.$.pipe(
@@ -47,7 +47,7 @@ export function spreadObjectStore$<T extends object>(
     }),
     mapAndCacheObjectElements(
       (_value, key) => key,
-      (_value, key) => source(key as keyof T),
+      (_value, key) => (source as Store<T>)(key as keyof T),
     ),
   );
 }

projects/app-state/src/typing-tests/spead-object-store.dts-spec.ts

@@ -0,0 +1,15 @@
+import { spreadObjectStore$, Store } from '../public-api';
+
+declare const object: Store<Record<string, number>>;
+declare const objectOrNull: Store<Record<string, number> | null>;
+declare const objectOrUndefined: Store<Record<string, number> | undefined>;
+declare const objectOrNil: Store<Record<string, number> | null | undefined>;
+
+// $ExpectType Observable<Store<number>[]>
+spreadObjectStore$(object);
+// $ExpectType Observable<Store<number>[]>
+spreadObjectStore$(objectOrNull);
+// $ExpectType Observable<Store<number>[]>
+spreadObjectStore$(objectOrUndefined);
+// $ExpectType Observable<Store<number>[]>
+spreadObjectStore$(objectOrNil);