fix(utils): fix compose method breaking initial state with meta reducers

Closes ngrx#247

modules/store/spec/modules.spec.ts

@@ -119,6 +119,40 @@ describe(`Store Modules`, () => {
     });
   });
 
+  describe(`: With initial state`, () => {
+    const initialState: RootState = { fruit: 'banana' };
+    const reducerMap: ActionReducerMap<RootState> = { fruit: rootFruitReducer };
+    const noopMetaReducer = (r: Function) => (state: any, action: any) => {
+      console.log('ACTION', state);
+      return r(state, action);
+    };
+
+    const testWithMetaReducers = (metaReducers: any[]) => () => {
+      beforeEach(() => {
+        TestBed.configureTestingModule({
+          imports: [
+            StoreModule.forRoot(reducerMap, { initialState, metaReducers }),
+          ],
+        });
+        store = TestBed.get(Store);
+      });
+      it('should have initial state', () => {
+        store.take(1).subscribe((s: any) => {
+          expect(s).toEqual(initialState);
+        });
+      });
+    };
+
+    describe(
+      'should add initial state with no meta reducers',
+      testWithMetaReducers([])
+    );
+    describe(
+      'should add initial state with a simple no-op meta reducer',
+      testWithMetaReducers([noopMetaReducer])
+    );
+  });
+
   describe(`: Nested`, () => {
     @NgModule({
       imports: [StoreModule.forFeature('a', featureAReducer)],

modules/store/src/utils.ts

@@ -72,15 +72,15 @@ export function compose<A, B, C, D, E, F>(
   b: (i: A) => B
 ): (i: A) => F;
 export function compose(...functions: any[]) {
-  return function(arg: any) {
+  return function(...arg: any[]) {
     if (functions.length === 0) {
       return arg;
     }
 
     const last = functions[functions.length - 1];
     const rest = functions.slice(0, -1);
 
-    return rest.reduceRight((composed, fn) => fn(composed), last(arg));
+    return rest.reduceRight((composed, fn) => fn(composed), last(...arg));
   };
 }