Returns the single element that satisfies test
.
Checks all 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, a StateError is thrown.
Source
E singleWhere(bool test(E element)) {
E result = null;
bool foundMatching = false;
for (E element in this) {
if (test(element)) {
if (foundMatching) {
throw IterableElementError.tooMany();
}
result = element;
foundMatching = true;
}
}
if (foundMatching) return result;
throw IterableElementError.noElement();
}