Dart Stream Example

gistfile1.dart

import 'dart:async';

class Cake {}
class Order {
  String type;
  Order(this.type);
}
    

void main() {
  
  final controller = new StreamController();
  final order = new Order('banana');
  
  final baker = new StreamTransformer.fromHandlers(
    handleData: (caketype, sink) {
      if (caketype == 'chocolate') {
        sink.add(new Cake());
      } else {
        sink.addError('I cant bake thats type !!');
      }
    }
  );
  
  controller.sink.add(order);
  controller.stream
    .map((order) => order.type)
    .transform(baker)
    .listen(
       (cake) => print('heres your cake $cake'),
       onError: (error) => print(error)
     );
}