How would I throw custom errors in a strategy?

[kyh]

I currently have a form strategy implemented as

export const signupStrategy = new FormStrategy(async ({ form }) => {
  const email = form.get("email") as string;
  const password = form.get("password") as string;

  const existingUser = await getUser({ email });

  if (existingUser) throw validationError("User already exists");

  const validation = validateData(
    { email, password },
    {
      email: () => validator.isEmail(email) ? undefined : "Invalid email",
      password: () => validator.isLength(password, { min: 5 }) ? undefined : "Password must be at least 5 characters long",
    }
  );

  if (validation.error) throw validation;

  const user = await createUser({ email, password });

  return user.id;
});

the validation object above is a custom error with the schema

{
  message: string;
  fields: { email: string; password: string }
  fieldErrors: { email: string | undefined; password: string | undefined }
  error: boolean;
}

I use this strategy in a action

export const action: ActionFunction = async ({ request }) => {
  try {
    return await authenticator.authenticate("signup", request, {
      successRedirect: "/",
      throwOnError: true,
    });
  } catch (error: any) {
    if (error instanceof Response) return error;
    // I want to be able to access my custom error here in order to highlight issues
    if (error instanceof AuthorizationError) return badRequest(error);
    return serverError(error);
  }
};

I was wondering if it's possible to access the custom error object with throwOnError

[unlinking]

For now, my workaround is throw new AuthorizationError(JSON.stringify(some error object)).
Preferably, remix-auth could extend AuthorizationError to store complex error object.