singleAsOptional property
Optional<T>
singleAsOptional
Returns an Optional
containing the only element of this list if it has
exactly one element, otherwise returns Optional.empty
.
This lookup can not distinguish between the list being empty and
containing the null
value as only element.
Methods like contains or length can be used if the distinction is
important.
Implementation
Optional<T> get singleAsOptional =>
getValueIf(length == 1, () => _list.single);