dart:collection

single property

E single

Checks that this iterable has only one element, and returns that element.

Throws a StateError if this is empty or has more than one element.

Source

E get single {
  if (_count == 0) throw IterableElementError.noElement();
  if (_count > 1) throw IterableElementError.tooMany();
  return _root.key;
}