flutter - How to Async/await in List.forEach() in Dart

Question

I'm writing some kind of bot (command line application) and I'm having trouble with async execution when I'm using the "forEach" method. Here is a simplified code of what I'm trying to do :

main() async {
  print("main start");
  await asyncOne();
  print("main end");
}

asyncOne() async {
  print("asyncOne start");
  [1, 2, 3].forEach(await (num) async {
    await asyncTwo(num);
  });
  print("asyncOne end");
}

asyncTwo(num) async
{
  print("asyncTwo #${num}");
}

And here is the output :

main start
asyncOne start
asyncOne end
main end
asyncTwo #1
asyncTwo #2
asyncTwo #3

What I'm trying to get is :

main start
asyncOne start
asyncTwo #1
asyncTwo #2
asyncTwo #3
asyncOne end
main end

If someone knows what I'm doing wrong I would appreciate it.

Answer 1

You need to use Future.forEach.

main() async {
  print("main start");
  await asyncOne();
  print("main end");
}

asyncOne() async {
  print("asyncOne start");
  await Future.forEach([1, 2, 3], (num) async {
    await asyncTwo(num);
  });
  print("asyncOne end");
}

asyncTwo(num) async
{
  print("asyncTwo #${num}");
}