result_type_dart

result_type_dart.dart

// Dart에서 ResultType 사용하기
// 출처: https://codewithandrea.com/articles/flutter-exception-handling-try-catch-result-type/

/* 1. 최초 정의 */
/// Base Result class
/// [S] represents the type of the success value
/// [E] should be [Exception] or a subclass of it
sealed class Result<S, E extends Exception> {
  const Result();
}

final class Success<S, E extends Exception> extends Result<S, E> {
  const Success(this.value);
  final S value;
}

final class Failure<S, E extends Exception> extends Result<S, E> {
  const Failure(this.exception);
  final E exception;
}


/* 2. Value를 전달하는 측 코드 */
try {
  final response = await _appAPI.dio.post(
    _appAPI.socialLogin,
    data: requestBody,
  );
  final loginResponse = LoginResponse.fromMap(response.data);
  if (loginResponse.data?.accessToken != null) {
    await tokenStorage.saveToken(loginResponse.data!.accessToken!);
  }

  return Success(loginResponse);
} catch (_) {
  throw Failure(LoginFailure());
}

/* 3. Value를 받는 측 코드 */
// 여기는 패턴 매칭을 사용하여 Success와 Failure를 분리한다.
final LoginResponse? response = switch (result) {
  Success(value: final response) => response,
  Failure(exception: final _) => null,
};