unique method

List<E> unique([
  1. Id id(
    1. E element
    )?,
  2. bool inplace = true
])

Implementation

List<E> unique([Id Function(E element)? id, bool inplace = true]) {
  final ids = Set();
  var list = inplace ? this : List<E>.from(this);
  list.retainWhere((x) => ids.add(id != null ? id(x) : x as Id));
  return list;
}