Formatting of async code aesthetics

[harry-dickson]

Newbie dart programmer; Dart 2.12.2 with VSCode. This is mostly an FYI in case you think this is a problem.

My code is bad enough, but the formatter makes it worse imho, in particular the decision to linebreak and indent .signInWithEmailLink and the first .catchError

  void onLink(DynamicLinkEvent event) {
    var link = event.data?.link?.toString();
    if (link != null && _firebaseAuth.isSignInWithEmailLink(link)) {
      var url = Uri.parse(event.data.link.queryParameters['continueUrl']);
      var email = url.queryParameters['e'];
      if (email != null) {
        _firebaseAuth
            .signInWithEmailLink(  // <== urgh!
          email: email,
          emailLink: link,
        )
            .catchError(  // <== argh!
          (error) {
            print('Auth Error $error');
          },
          test: (e) => e is FirebaseAuthException,
        ).catchError(
          () {},
        );
      }
    }
  }

It annoyed me so much I did this :)

  void onLink(DynamicLinkEvent event) {
    var link = event.data?.link?.toString();
    if (link != null && _firebaseAuth.isSignInWithEmailLink(link)) {
      var url = Uri.parse(event.data.link.queryParameters['continueUrl']);
      var email = url.queryParameters['e'];
      if (email != null) {
        var f = _firebaseAuth.signInWithEmailLink(
          email: email,
          emailLink: link,
        );
        // [f] is a workaround for formatter ugliness
        f.catchError(
          (error) {
            print('Auth Error $error');
          },
          test: (e) => e is FirebaseAuthException,
        ).catchError(
          () {},
        );
      }
    }
  }

[munificent]

This is mostly a consequence of the weird interaction between how trailing commas affect formatting and the formatting rules around lambdas in argument lists. If you remove the trailing commas, you get:

void onLink(DynamicLinkEvent event) {
  var link = event.data?.link?.toString();
  if (link != null && _firebaseAuth.isSignInWithEmailLink(link)) {
    var url = Uri.parse(event.data.link.queryParameters['continueUrl']);
    var email = url.queryParameters['e'];
    if (email != null) {
      _firebaseAuth
          .signInWithEmailLink(email: email, emailLink: link)
          .catchError((error) {
        print('Auth Error $error');
      }, test: (e) => e is FirebaseAuthException).catchError(() {});
    }
  }
}

I think that's a lot more reasonable. But I agree that the behavior in the presence of trailing commas is pretty bad. I'll leave this open to take a look at improving that.

[munificent]

With the forthcoming tall style, it looks like:

  void onLink(DynamicLinkEvent event) {
    var link = event.data?.link?.toString();
    if (link != null && _firebaseAuth.isSignInWithEmailLink(link)) {
      var url = Uri.parse(event.data.link.queryParameters['continueUrl']);
      var email = url.queryParameters['e'];
      if (email != null) {
        _firebaseAuth
            .signInWithEmailLink(email: email, emailLink: link)
            .catchError((error) {
              print('Auth Error $error');
            }, test: (e) => e is FirebaseAuthException)
            .catchError(() {});
      }
    }
  }

That looks decent to me.