filter.dart

typedef bool Predicate(T);

List<T> filter<T>(List<T> list, Predicate predicate) {
  final newList = [];

  for (final item in list) {
    if (predicate(item)) {
      newList.add(item);
    }
  }

  return newList;
}

void main() {
  final filtered = filter([1, 2, 3, 4, 5], (item) => item % 2 == 1);

  assert(filtered.length == 3);

  print(filtered);
}