Make go() asynchronous

[johnpryan]

If we are making redirection asynchronous (#105808) we should also make go() and goNamed() asynchronous. We should also make push and pushNamed asynchronous, but it's not specified how redirection is handled for push methods.

Context: #105808 (comment)

[NazarenoCavazzon]

Hi Guys, I made a PR for solving other issue that might as well solve this one, you can take a look flutter/packages#2416. The only change that I would need to make in order to make it work for you guys is making the go method also asynchronous.

[cedvdb]

I'll reiterate here as there was some discussion as whether or not to make it asynchronous in another issue:

• there are valid use cases where you have to wait for the navigation to complete to do something (eg reset something in a non UI layer, not needing context).
• the other solution provided is just a trick to hide the asynchronous nature, and is just indirection on top of an operation that is async behind the curtains which doesn't strike me as a good idea / api.
• the fact that context is inaccessible makes sens, documentation should prevent missuses.
• it makes testing easier

Not doing this will result in lots of annoyance and needless indirection in my experience (I also have a router library and this has proven to be a must have).

[Lzyct]

Any update about this issue?

[cmz-one]

This is an ugly method until the official has not been modified.

final GoRouter router = GoRouter(
  observers: [FutureNavigatorObserver()],
  routes: ...,
);

class FutureNavigatorObserver extends NavigatorObserver {
  @override
  void didPop(Route route, Route? previousRoute) async {
    super.didPop(route, previousRoute);
    FutureGoRouter.didPop(route.settings.name, await route.popped);
  }
}

class FutureGoRouter {
  static final List<_FutureGoItem> _asyncList = [];

  /// [path] Add new parameter ,it must equal to [route.settings.name]
  static FutureOr<T?> go<T>(String location, String path, {Object? extra}) {
    router.go(location, extra: extra);
    Completer<T?> completer = Completer();
    _asyncList.add(_FutureGoItem(path, completer));
    return completer.future;
  }

  /// the [routeSettingName] must equal to [path]
  static void didPop(String? routeSettingName, dynamic popped) {
    _FutureGoItem? asyncItem;
    for (int i = 0; i < _asyncList.length; i++) {
      if (_asyncList[i].path == routeSettingName) {
        asyncItem = _asyncList[i];
      }
    }
    if (asyncItem != null) {
      _asyncList.remove(asyncItem);
      asyncItem.completer.complete(popped);
    }
  }
}

class _FutureGoItem {
  final String path;
  final Completer completer;

  _FutureGoItem(this.path, this.completer);
}

How to use?

final result = await FutureGoRouter.go<int>('/test?a=1&b=2','test');
...
router.pop(999);