Create a stream watching a list? - flutter

Question

I've got a global list like this:
var data = [1,2,3];
I will add more elements to it, and each time I do I want something else to be notified - I need a stream and listener. So can I make a stream and tell it to run sink.add anytime the list mutates?
var stream = Stream.fromIterable(data);
stream.listen((item) => print(item));
> 1
> 2
> 3
data.add(4);
> Uncaught Error: Concurrent modification during iteration
data.remove(3);
> Uncaught Error: Concurrent modification during iteration
Oh no. What can I do to make this work?

Answer 1

This might help:
import 'dart:async';
class ObservableList<T> {
final _list = <T>[];
final _itemAddedStreamController = StreamController<T>();
final _listStreamController = StreamController<List<T>>();
Stream get itemAddedStream => _itemAddedStreamController.stream;
Stream get listStream => _listStreamController.stream;
void add(T value) {
_list.add(value);
_itemAddedStreamController.add(value);
_listStreamController.add(_list);
}
void dispose() {
_listStreamController.close();
_itemAddedStreamController.close();
}
}
void main() {
final observableList = ObservableList<int>();
observableList.itemAddedStream.listen((value) => print(value));
observableList.add(1);
observableList.add(2);
observableList.add(3);
observableList.add(4);
}