List slicing with step parameter in Dart

main.dart

extension ListSlice<T> on List<T> {
  List<T> slice([int start = 0, int? end, int step = 1]) {
    end ??= this.length;
    return [for (var i = start; i < end; i += step) this[i]];
  }
}

void main() {
  final list1 = [for (var i = 1; i <= 20; ++i) i];

//  Example - 1
  final result = list1.slice(1, 4);
  print(result); // [2, 3, 4]

  //Example - 2
  final result2 = list1.slice(10);
  print(result2); // [11, 12, 13, 14, 15, 15, 17, 18, 19, 20]

  //Example - 3
  final result4 = list1.slice(4, 10, 2);
  print(result4); // [5, 7, 9]

  //Example - 4
  final result3 = list1.slice();
  print(result3); // [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 15, 17, 18, 19, 20]
}