chore: review fixes

modules/store/src/index.ts

@@ -59,5 +59,9 @@ export {
   StoreFeatureModule,
 } from './store_module';
 export { RootStoreConfig, StoreConfig, FeatureSlice } from './store_config';
-export { provideStore, provideState } from './provide_store';
+export {
+  provideStore,
+  provideState,
+  FEATURE_STATE_PROVIDER,
+} from './provide_store';
 export { ReducerTypes, on, createReducer } from './reducer_creator';

modules/store/src/provide_store.ts

@@ -65,37 +65,47 @@ import {
   _provideForRootGuard,
 } from './store_config';
 
+/**
+ * InjectionToken that registers feature states.
+ * Mainly used to provide a hook that can be injected
+ * to ensure feature state is loaded before something
+ * that depends on it.
+ */
+export const FEATURE_STATE_PROVIDER = new InjectionToken('NgRx Feature State', {
+  factory() {
+    const features = inject<StoreFeature<any, any>[]>(_STORE_FEATURES);
+    const featureReducers = inject<ActionReducerMap<any>[]>(FEATURE_REDUCERS);
+    const reducerManager = inject(ReducerManager);
+    inject(_ACTION_TYPE_UNIQUENESS_CHECK, InjectFlags.Optional);
+
+    const feats = features.map((feature, index) => {
+      const featureReducerCollection = featureReducers.shift();
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+      const reducers = featureReducerCollection! /*TODO(#823)*/[index];
+
+      return {
+        ...feature,
+        reducers,
+        initialState: _initialStateFactory(feature.initialState),
+      };
+    });
+
+    reducerManager.addFeatures(feats);
+  },
+});
+
 /**
  * Environment Initializer used in the feature
  * providers to register state features
  */
 const ENVIRONMENT_STATE_PROVIDER: Provider[] = [
+  { provide: FEATURE_STATE_PROVIDER, deps: [], useValue: true },
   {
     provide: ENVIRONMENT_INITIALIZER,
     multi: true,
     deps: [],
     useFactory() {
-      return () => {
-        const features = inject<StoreFeature<any, any>[]>(_STORE_FEATURES);
-        const featureReducers =
-          inject<ActionReducerMap<any>[]>(FEATURE_REDUCERS);
-        const reducerManager = inject(ReducerManager);
-        inject(_ACTION_TYPE_UNIQUENESS_CHECK, InjectFlags.Optional);
-
-        const feats = features.map((feature, index) => {
-          const featureReducerCollection = featureReducers.shift();
-          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-          const reducers = featureReducerCollection! /*TODO(#823)*/[index];
-
-          return {
-            ...feature,
-            reducers,
-            initialState: _initialStateFactory(feature.initialState),
-          };
-        });
-
-        reducerManager.addFeatures(feats);
-      };
+      return () => inject(FEATURE_STATE_PROVIDER);
     },
   },
 ];
@@ -315,18 +325,18 @@ const ENVIRONMENT_STORE_PROVIDER = [
  * ```
  */
 export function provideStore<T, V extends Action = Action>(
-  reducers: ActionReducerMap<T, V> | InjectionToken<ActionReducerMap<T, V>>,
+  reducers?: ActionReducerMap<T, V> | InjectionToken<ActionReducerMap<T, V>>,
   config?: RootStoreConfig<T, V>
 ): ImportedNgModuleProviders;
 export function provideStore(
-  reducers:
+  reducers?:
     | ActionReducerMap<any, any>
     | InjectionToken<ActionReducerMap<any, any>>,
   config: RootStoreConfig<any, any> = {}
 ): ImportedNgModuleProviders {
   return {
     ɵproviders: [
-      ..._provideStore(reducers, config),
+      ..._provideStore(reducers || {}, config),
       ENVIRONMENT_STORE_PROVIDER,
     ],
   };

modules/store/src/store_config.ts

@@ -101,7 +101,7 @@ export function _concatMetaReducers(
 export function _provideForRootGuard(store: Store<any>): any {
   if (store) {
     throw new TypeError(
-      `StoreModule.forRoot() called twice. Feature modules should use StoreModule.forFeature() instead.`
+      `The root Store has been provided more than once. Feature modules should provide feature states instead.`
     );
   }
   return 'guarded';