# single property

1. @override

E get single
override

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. This operation will not iterate past the second element.

## Implementation

    @override
    E get single {
      if (_size != 1) {
        throw IllegalStateException('Expected single element, but got $_size');
      }
      return first;
    }