Map methods return List<List<Object>> Instead of List<Object>

final listTruckFruits = event.trucks
        .map((truck) => truck.fruits
            .map(
              (fruit) => TruckFruit(
                truckOrigin: truck.info.origin,
                fruitType: fruit.type,
              ),
            )
            .toList())
        .toList();

I’m trying to map multiple List<Fruit> from List<Truck>

class Truck {
  final List<Fruit> fruits;

  Truck({
    required this.fruits,
  });
}

class Fruit {
  final String type;
  Fruit({
    required this.type,
  });
}

into a List<TruckFruit> but currently what is returned from my two map methods listTruckFruits all above is a List<List<TruckFruit>> while a want List<TruckFruit>

class TruckFruit {
  final String fruitType;
  final String truckOrigin;

  TruckFruit({
    required this.fruitType,
    required this.truckOrigin,
  });
}

>Solution :

You can use Iterable.expand() to flatten your list of lists:

final simpleListOfAllFruitsOnAllTrucks = listTruckFruits.expand((x) => x).toList();

You could also use this to not generate a list of lists in the first place, by using it on your event.trucks instead of your first map.