Stream.error constructor - Stream - dart:async library (original) (raw)

1. @Since("2.5")

Stream<T>.error(

1. Object error, [
2. StackTrace? stackTrace ])

Creates a stream which emits a single error event before completing.

This stream emits a single error event of error and stackTraceand then completes with a done event.

Example:

Future<void> tryThings(Stream<int> data) async {
  try {
    await for (var x in data) {
      print('Data: $x');
    }
  } catch (e) {
    print(e);
  }
}
tryThings(Stream<int>.error('Error')); // prints "Error".

The returned stream is effectively equivalent to one created byFuture<T>.error(error, stackTrace).asStream(), by or(() async* { throw error; } ()), except that you can control the stack trace as well.

Implementation

@Since("2.5")
factory Stream.error(Object error, [StackTrace? stackTrace]) {
  AsyncError(:error, :stackTrace) = _interceptUserError(error, stackTrace);
  return (_AsyncStreamController<T>(null, null, null, null)
        .._addError(error, stackTrace)
        .._closeUnchecked())
      .stream;
}