singleWhere method
inherited
Returns the single element that satisfies test.
Checks elements to see if test(element) returns true.
If exactly one element satisfies test, that element is returned.
Otherwise, if there are no matching elements, or if there is more than
one matching element, the result of invoking the orElse
function is returned.
If orElse is omitted, it defaults to throwing a StateError.
Implementation
E singleWhere(bool test(E element), {E orElse()}) {
return _base.singleWhere(test, orElse: orElse);
}