getPizzas$ = this.actions$.pipe(
  ofType<GetAllPizzas>(PizzaTypes.GetPizzas,
  withLatestFrom(
    this.store$.pipe(select(fromRootStore.getPizzaId))
  ),
  take(1),
  exhaustMap(([customAction, pizzaId]): any => {  // << assuming this is correct
    if (!pizzaId) {
      map(() => new BigProductError({ .   /// <<< is this how we approach this? just map? or should we return something?
           appmessage : "Boom"
      }));
    } .      /// <<< will control go beyond this point or is this more of an if-else condition?
    return this.pizzaService.getPizzas(customAction.orderDetails, pizzaId)
      .pipe(
        map((pizzas) => new LoadPizzasSuccess(pizzas)),
        catchError(error => of(new LoadPizzasFailure(error)))
      );
  })
);

describe('GetPizzas', () => {
    test(`
      Get Pizzas successfully
    `, () => {
      const action = new GetAllPizzas();
      const success = new GetAllPizzasSuccess({'NumberOfPizzas': 2});

      actions$ = hot('-a', { a: action });
      const resp = cold('-a|', { a: { NumberOfPizzas: 2 } });
      const exp = cold('--a', { a: success });
      pizzaService.getPizzas = jest.fn(() => resp);

      expect(effects.pizzaService$).toBeObservable(exp);
    });

Expected value to equal:
      [{"frame": 20, "notification": {"error": undefined, "hasValue": true, "kind": "N", "value": {"payload": {"NumberOfPizzas": 2}, "type": "[Pizzas API] Get All Pizzas Success"}}}]
  Received:
      [{"frame": 20, "notification": {"error": undefined, "hasValue": true, "kind": "N", "value": {"payload": {"NumberOfPizzas": 2}, "type": "[[Pizzas API] Get All Pizzas Success"}}}, {"frame": 30, "notification": {"error": undefined, "hasValue": false, "kind": "C", "value": undefined}}]