future_zips_sample.dart

extension FutureZipX<T> on Future<T> {
  Future<(T, T2)> zipWith<T2>(Future<T2> future2) async {
    late T result1;
    late T2 result2;
    await Future.wait(
        [then((it) => result1 = it), future2.then((it) => result2 = it)]);
    return (result1, result2);
  }
}

extension TupleFuture2X<T1, T2> on (Future<T1>, Future<T2>) {
  Future<(T1, T2)> wait() async {
    final (a, b) = this;
    return (await a, await b);
  }
}

class UserProfile {
  final String? a;
  final String? b;
  final String? c;
  final int? d;
  final bool? e;
  const UserProfile([this.a, this.b, this.c, this.d, this.e]);
  
  @override String toString() => "$a, $b, $c, $d, $e";
}



void main() async {
  await () async {
    final (a, b) =
    await Future.value("a")
      .zipWith(Future.value("b"));
    print(UserProfile(a, b));
  }();
  await () async {
    final ((a, b), c) =
    await Future.value("a")
      .zipWith(Future.value("b"))
      .zipWith(Future.value("c"));
    print(UserProfile(a, b, c));
  }();
  await () async {
    final (((a, b), c), d) =
    await Future.value("a")
      .zipWith(Future.value("b"))
      .zipWith(Future.value("c"))
      .zipWith(Future.value(4));
    print(UserProfile(a, b, c, d));
  }();
  await () async {
    final (a, d) = await (
      Future.value("a1"),
      Future.value(4),
    ).wait();
    print(UserProfile(a, "b", "c", d));
  }();
}