feat(store): dispatch one update action when features are added or removed (#1240)

BREAKING CHANGE:

BEFORE:
```ts
{type: '@ngrx/store/update-reducers', feature: 'feature1'}
{type: '@ngrx/store/update-reducers', feature: 'feature2'}
```

AFTER:
```ts
{type: '@ngrx/store/update-reducers', features: ['feature1',
'feature2']}
```

Author: timdeschryver

modules/store/spec/store.spec.ts

@@ -337,15 +337,15 @@ describe('ngRx Store', () => {
       store.addReducer(key, counterReducer);
       expect(reducerManagerDispatcherSpy).toHaveBeenCalledWith({
         type: UPDATE,
-        feature: key,
+        features: [key],
       });
     });
 
     it('should dispatch an update reducers action when a reducer is removed', () => {
       store.removeReducer(key);
       expect(reducerManagerDispatcherSpy).toHaveBeenCalledWith({
         type: UPDATE,
-        feature: key,
+        features: [key],
       });
     });
   });
@@ -373,11 +373,11 @@ describe('ngRx Store', () => {
 
       expect(reducerManagerDispatcherSpy).toHaveBeenCalledWith({
         type: UPDATE,
-        feature: 'feature1',
+        features: ['feature1'],
       });
     });
 
-    it('should dispatch an update reducers action for each feature that is added', () => {
+    it('should dispatch an update reducers action when multiple features are added', () => {
       reducerManager.addFeatures([
         createFeature({
           key: 'feature1',
@@ -387,18 +387,10 @@ describe('ngRx Store', () => {
         }),
       ]);
 
-      expect(reducerManagerDispatcherSpy).toHaveBeenCalledTimes(2);
-
-      // get the first argument for the first call
-      expect(reducerManagerDispatcherSpy.calls.argsFor(0)[0]).toEqual({
-        type: UPDATE,
-        feature: 'feature1',
-      });
-
-      // get the first argument for the second call
-      expect(reducerManagerDispatcherSpy.calls.argsFor(1)[0]).toEqual({
+      expect(reducerManagerDispatcherSpy).toHaveBeenCalledTimes(1);
+      expect(reducerManagerDispatcherSpy).toHaveBeenCalledWith({
         type: UPDATE,
-        feature: 'feature2',
+        features: ['feature1', 'feature2'],
       });
     });
 
@@ -411,11 +403,11 @@ describe('ngRx Store', () => {
 
       expect(reducerManagerDispatcherSpy).toHaveBeenCalledWith({
         type: UPDATE,
-        feature: 'feature1',
+        features: ['feature1'],
       });
     });
 
-    it('should dispatch an update reducers action for each feature that is removed', () => {
+    it('should dispatch an update reducers action when multiple features are removed', () => {
       reducerManager.removeFeatures([
         createFeature({
           key: 'feature1',
@@ -425,16 +417,10 @@ describe('ngRx Store', () => {
         }),
       ]);
 
-      // get the first argument for the first call
-      expect(reducerManagerDispatcherSpy.calls.argsFor(0)[0]).toEqual({
-        type: UPDATE,
-        feature: 'feature1',
-      });
-
-      // get the first argument for the second call
-      expect(reducerManagerDispatcherSpy.calls.argsFor(1)[0]).toEqual({
+      expect(reducerManagerDispatcherSpy).toHaveBeenCalledTimes(1);
+      expect(reducerManagerDispatcherSpy).toHaveBeenCalledWith({
         type: UPDATE,
-        feature: 'feature2',
+        features: ['feature1', 'feature2'],
       });
     });
 

modules/store/src/reducer_manager.ts

@@ -92,12 +92,9 @@ export class ReducerManager extends BehaviorSubject<ActionReducer<any, any>>
 
   private updateReducers(featureKeys: string[]) {
     this.next(this.reducerFactory(this.reducers, this.initialState));
-
-    featureKeys.forEach(feature => {
-      this.dispatcher.next(<Action>{
-        type: UPDATE,
-        feature,
-      });
+    this.dispatcher.next(<Action>{
+      type: UPDATE,
+      features: featureKeys,
     });
   }