From 38e9cc10f509cc6c1ab1bc1505e4bacc10a98fad Mon Sep 17 00:00:00 2001
From: timdeschryver <28659384+timdeschryver@users.noreply.github.com>
Date: Sun, 10 Mar 2019 18:07:23 +0100
Subject: [PATCH] fix(Store): invoke meta reducers before user defined meta
 reducers

---
 modules/store/spec/runtime_checks.spec.ts | 42 +++++++++++++++++++++++
 modules/store/src/store_module.ts         | 16 ++++-----
 2 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/modules/store/spec/runtime_checks.spec.ts b/modules/store/spec/runtime_checks.spec.ts
index 3dc259a7a7..67200f9b47 100644
--- a/modules/store/spec/runtime_checks.spec.ts
+++ b/modules/store/spec/runtime_checks.spec.ts
@@ -5,6 +5,7 @@ import {
   RuntimeChecks,
   Store,
   StoreModule,
+  META_REDUCERS,
 } from '..';
 
 describe('Runtime checks:', () => {
@@ -42,6 +43,47 @@ describe('Runtime checks:', () => {
     });
   });
 
+  describe('Order of meta reducers:', () => {
+    it('should invoke meta reducers before user defined meta reducers', () => {
+      let logs: string[] = [];
+      function metaReducerFactory(logMessage: string) {
+        return function metaReducer(reducer: any) {
+          return function(state: any, action: any) {
+            logs.push(logMessage);
+            return reducer(state, action);
+          };
+        };
+      }
+
+      TestBed.configureTestingModule({
+        imports: [
+          StoreModule.forRoot(
+            {},
+            {
+              metaReducers: [metaReducerFactory('user')],
+            }
+          ),
+        ],
+        providers: [
+          {
+            provide: META_REDUCERS,
+            useValue: metaReducerFactory('ngrx'),
+            multi: true,
+          },
+        ],
+      });
+
+      const store: Store<any> = TestBed.get(Store);
+      const expected = ['ngrx', 'user'];
+
+      expect(logs).toEqual(expected);
+      logs = [];
+
+      store.dispatch({ type: 'foo' });
+      expect(logs).toEqual(expected);
+    });
+  });
+
   describe('State Serialization:', () => {
     const invalidAction = () => ({ type: ErrorTypes.UnserializableState });
 
diff --git a/modules/store/src/store_module.ts b/modules/store/src/store_module.ts
index fdfd6f5bda..121de3516a 100644
--- a/modules/store/src/store_module.ts
+++ b/modules/store/src/store_module.ts
@@ -135,7 +135,7 @@ export class StoreModule {
         },
         {
           provide: _RESOLVED_META_REDUCERS,
-          deps: [USER_PROVIDED_META_REDUCERS, META_REDUCERS],
+          deps: [META_REDUCERS, USER_PROVIDED_META_REDUCERS],
           useFactory: _concatMetaReducers,
         },
         {
@@ -234,8 +234,7 @@ export class StoreModule {
 
 export function _createStoreReducers(
   injector: Injector,
-  reducers: ActionReducerMap<any, any>,
-  tokenReducers: ActionReducerMap<any, any>
+  reducers: ActionReducerMap<any, any>
 ) {
   return reducers instanceof InjectionToken ? injector.get(reducers) : reducers;
 }
@@ -263,10 +262,9 @@ export function _createFeatureStore(
 
 export function _createFeatureReducers(
   injector: Injector,
-  reducerCollection: ActionReducerMap<any, any>[],
-  tokenReducerCollection: ActionReducerMap<any, any>[]
+  reducerCollection: ActionReducerMap<any, any>[]
 ) {
-  const reducers = reducerCollection.map((reducer, index) => {
+  const reducers = reducerCollection.map(reducer => {
     return reducer instanceof InjectionToken ? injector.get(reducer) : reducer;
   });
 
@@ -282,8 +280,8 @@ export function _initialStateFactory(initialState: any): any {
 }
 
 export function _concatMetaReducers(
-  userProvidedMetaReducers: MetaReducer[],
-  metaReducers: MetaReducer[]
+  metaReducers: MetaReducer[],
+  userProvidedMetaReducers: MetaReducer[]
 ): MetaReducer[] {
-  return userProvidedMetaReducers.concat(metaReducers);
+  return metaReducers.concat(userProvidedMetaReducers);
 }