Streams trong Dart

void main() async {
  var stream = Stream.fromIterable([1, 2, 3, 4, 5]);
  
  await for (var value in stream) {
    print(value);
  }
}

Stream<int> countStream(int max) async* {
  for (int i = 1; i <= max; i++) {
    await Future.delayed(Duration(seconds: 1));
    yield i;
  }
}
 
void main() async {
  await for (var count in countStream(5)) {
    print(count);
  }
}

import 'dart:async';
 
void main() async {
  var controller = StreamController<int>();
  
  // Listen to stream
  controller.stream.listen(
    (data) => print('Received: $data'),
    onError: (error) => print('Error: $error'),
    onDone: () => print('Done'),
  );
  
  // Add data
  controller.sink.add(1);
  controller.sink.add(2);
  controller.sink.add(3);
  
  await controller.close();
}

void main() {
  var controller = StreamController<int>.broadcast();
  
  // Nhiều listeners
  controller.stream.listen((data) => print('Listener 1: $data'));
  controller.stream.listen((data) => print('Listener 2: $data'));
  
  controller.add(1);
  controller.add(2);
}

void main() async {
  var stream = Stream.fromIterable([1, 2, 3, 4, 5]);
  
  // map
  await stream.map((n) => n * 2).forEach(print);
  // 2, 4, 6, 8, 10
  
  // where (filter)
  var stream2 = Stream.fromIterable([1, 2, 3, 4, 5]);
  await stream2.where((n) => n % 2 == 0).forEach(print);
  // 2, 4
  
  // take
  var stream3 = Stream.fromIterable([1, 2, 3, 4, 5]);
  await stream3.take(3).forEach(print);
  // 1, 2, 3
}

Stream<int> timerStream() {
  return Stream.periodic(
    Duration(seconds: 1),
    (count) => count,
  ).take(5);
}
 
void main() async {
  await for (var count in timerStream()) {
    print('Tick: $count');
  }
}

StreamBuilder<int>(
  stream: countStream(10),
  builder: (context, snapshot) {
    if (snapshot.hasError) {
      return Text('Error: ${snapshot.error}');
    }
    if (!snapshot.hasData) {
      return CircularProgressIndicator();
    }
    return Text('Count: ${snapshot.data}');
  },
)

void main() async {
  var stream1 = Stream.fromIterable([1, 2, 3]);
  var stream2 = Stream.fromIterable([4, 5, 6]);
  
  // Concat
  var combined = StreamGroup.merge([stream1, stream2]);
  await combined.forEach(print);
}

void main() {
  var controller = StreamController<int>();
  
  controller.stream.listen(
    (data) => print('Data: $data'),
    onError: (error) => print('Error: $error'),
    cancelOnError: false,  // Tiếp tục sau lỗi
  );
  
  controller.add(1);
  controller.addError('Something went wrong');
  controller.add(2);  // Vẫn nhận được
}