Dart vs Kotlin: extension functions

extension_functions.dart

extension NumberExtensions on String {
  int parseInt() {
    return int.parse(this);
  }
}

extension ListExtensions<T> on List<T> {
  List<List<T>> split(int at) {
    return [sublist(0, at), sublist(at)];
  }
}

void main() {
  final num = "42".parseInt();
  final subLists = [0, 1, 2, 3, 4].split(2);
}

extension_functions.kt

fun String.parseInt(): Int {
    return this.toInt()
}

fun <T> List<T>.split(at: Int): List<List<T>> {
    return listOf(subList(0, at), subList(at, size))
}

fun main() {
    val num = "42".parseInt()
    val subLists = listOf(0, 1, 2, 3, 4).split(2)
}