takeWhile method
Forwards data events while test
is successful.
Returns a stream that provides the same events as this stream
until test
fails for a data event.
The returned stream is done when either this stream is done,
or when this stream first emits a data event that fails test
.
The test
call is considered failing if it returns a non-true
value
or if it throws. If the test
call throws, the error is emitted as the
last event on the returned streams.
Stops listening to this stream after the accepted elements.
Internally the method cancels its subscription after these elements. This means that single-subscription (non-broadcast) streams are closed and cannot be reused after a call to this method.
The returned stream is a broadcast stream if this stream is. For a broadcast stream, the events are only tested from the time the returned stream is listened to.
Example:
final stream = Stream<int>.periodic(const Duration(seconds: 1), (i) => i)
.takeWhile((event) => event < 6);
stream.forEach(print); // Outputs events: 0, ..., 5.
Implementation
@override
Stream<T> takeWhile(bool Function(T element) test) => stream.takeWhile(test);