dart_stream.dart

dart_stream.dart

import 'dart:async';

main() async {
  await periodicStreamSample();
//   await streamControllerSample();
//   await streamControllerWithPeriodicEmitsAndWaiterSample();
}

Future<void> periodicStreamSample() async {
  final subscription = Stream.periodic(
    Duration(seconds: 1),
    (value) => value,
  ).listen(print);

  await Future.delayed(Duration(seconds: 10));
  subscription.cancel();
}

Future<void> streamControllerSample() async {
  // StreamController has 1 listener
  final streamController = StreamController();
  // Accessing the stream and listening for data event
  final streamControllerSubscription = streamController.stream.listen((data) {
    print('Got eem! $data');
  }, onDone: () {
    print("Task Done");
  }, onError: (error) {
    print("Some Error");
  });

  streamController.sink.add('event1');
  streamController.sink.add('event2');
  streamController.sink.add('event3');
  streamController.sink.add('event4');

  await Future.delayed(Duration(seconds: 1));
  streamControllerSubscription.cancel();
  streamController.close();
}

Future<void> streamControllerWithPeriodicEmitsAndWaiterSample() async {
  final streamController = StreamController<String>.broadcast();
  // Accessing the stream and listening for data event
  final streamControllerSubscription = streamController.stream.listen((data) {
    print('Got eem! $data');
  });
  final subscription = Stream.periodic(
    Duration(seconds: 1),
    (value) => value,
  ).listen((data) => streamController.sink.add('event$data'));
  await streamController.stream.firstWhere((event) => event == 'event3',
      orElse: () => 'event not found');
  subscription.cancel();
  streamControllerSubscription.cancel();
  print('cancel subscriptions');
  streamController.close();
  print('close streem');
}