header, isNavBarCollapsed observable: filter out undefined state that can occur when using AoT compilation

src/app/app.component.ts

@@ -37,6 +37,13 @@ export class AppComponent implements OnDestroy, OnInit {
     translate.setDefaultLang('en');
     // the lang to use, if the lang isn't available, it will use the current loader to get them
     translate.use('en');
+
+    this.onResize({
+      target: {
+        innerWidth: 800,
+        innerHeight: 600
+      }
+    });
   }
 
   ngOnInit() {

src/app/app.effects.ts

@@ -1,6 +1,6 @@
 import { EffectsModule } from "@ngrx/effects";
 import { HeaderEffects } from "./header/header.effects";
 
-export default [
+export const effects = [
   EffectsModule.run(HeaderEffects)
 ];

src/app/app.module.ts

@@ -11,8 +11,8 @@ import { StoreModule } from "@ngrx/store";
 import { RouterStoreModule } from "@ngrx/router-store";
 import { StoreDevtoolsModule } from "@ngrx/store-devtools";
 
-import reducers from './app.reducers';
-import effects from './app.effects';
+import { reducers } from './app.reducers';
+import { effects } from './app.effects';
 
 @NgModule({
   declarations: [

src/app/app.reducers.ts

@@ -1,7 +1,7 @@
 import { headerReducer } from './header/header.reducer';
 import { hostWindowReducer } from "./shared/host-window.reducer";
 
-export default {
+export const reducers = {
   headerReducer,
   hostWindowReducer
 }

src/app/header/header.component.ts

@@ -3,6 +3,7 @@ import { Store } from "@ngrx/store";
 import { HeaderState } from "./header.reducer";
 import { HeaderActions } from "./header.actions";
 import { Observable } from "rxjs";
+import 'rxjs/add/operator/filter';
 
 @Component({
   selector: 'ds-header',
@@ -19,6 +20,9 @@ export class HeaderComponent implements OnInit {
 
   ngOnInit(): void {
     this.isNavBarCollapsed = this.store.select('headerReducer')
+      //ensure that state is not null, can happen when using AoT compilation
+      .filter((state: HeaderState) => state !== null && state !== undefined)
+      //unwrap navCollapsed
       .map(({ navCollapsed }: HeaderState) => navCollapsed);
   }