whereIndexed method
Implementation
Iterable<ListIndex<T>> whereIndexed([bool filter(T item)?]) {
Iterable<ListIndex<T>> indexed = this != null
? this!.indexed() as Iterable<ListIndex<T>>
: <ListIndex<T>>[];
if (filter != null) {
indexed = indexed.where((li) => filter(li.value));
}
return indexed;
}