no more build errors, still issues with the selectors not returning anything

src/app/app.effects.ts

@@ -1,11 +1,8 @@
-import { EffectsModule } from '@ngrx/effects';
 
 import { HeaderEffects } from './header/header.effects';
 import { StoreEffects } from './store.effects';
-import { coreEffects } from './core/core.effects';
 
-export const effects = [
-  ...coreEffects, // TODO: should probably be imported in coreModule
-  EffectsModule.run(StoreEffects),
-  EffectsModule.run(HeaderEffects)
+export const appEffects = [
+  StoreEffects,
+  HeaderEffects
 ];