fold<S> method
Combines a sequence of values by repeatedly applying combine
.
Similar to Iterable.fold, this function maintains a value,
starting with initialValue
and updated for each element of
this stream.
For each element, the value is updated to the result of calling
combine
with the previous value and the element.
When this stream is done, the returned future is completed with
the value at that time.
For an empty stream, the future is completed with initialValue
.
If this stream emits an error, or the call to combine
throws,
the returned future is completed with that error,
and processing is stopped.
Example:
final result = await Stream.fromIterable([2, 6, 10, 8, 2])
.fold<int>(10, (previous, element) => previous + element);
print(result); // 38
Implementation
@override
Future<S> fold<S>(
S initialValue,
S Function(S previous, T element) combine,
) =>
stream.fold(initialValue, combine);