flutter_resultable #

A lightweight, expressive Result type for Flutter and Dart to model success and failure outcomes without using exceptions, inspired by functional programming patterns like Either.

✨ Features #

• ✅ Result.success(S) and Result.failure(F) to represent outcomes cleanly.
• 🔁 Pattern matching via when, map, and maybeWhen (thanks to freezed).
• ⚡ Strongly typed failure and success handling.
• 🧠 Utility extensions:
  • isSuccess, isFailure
  • successOrNull, failureOrNull
  • getOrElse(fallback)
  • fold(onFailure, onSuccess)
• 💡 Easily testable and composable.
• 🪶 Minimal, clean API.

📦 Installation #

Add this to your pubspec.yaml:

dependencies:
  flutter_resultable: ^0.0.3

Then run:

flutter pub get

🔧 Usage #

Define a result-returning function #

import 'package:flutter_resultable/flutter_resultable.dart';

Result<String, int> divide(int a, int b) {
  if (b == 0) return Result.failure("Division by zero");
  return Result.success(a ~/ b);
}

Handle with pattern matching #

final result = divide(10, 2);

result.when(
  failure: (error) => print("Error: $error"),
  success: (value) => print("Result: $value"),
);

Use maybeWhen for optional handling #

result.maybeWhen(
  success: (value) => print("Success with $value"),
  orElse: () => print("Something went wrong"),
);

Use fold for cleaner branching #

result.fold(
  (error) => print("Error: $error"),
  (value) => print("Value: $value"),
);

Use getOrElse to provide a fallback value #

final value = result.getOrElse((error) => -1); // returns 5 or -1

Check result state or access nullable values #

if (result.isSuccess) {
  print(result.successOrNull);
} else {
  print(result.failureOrNull);
}

📘 API #

sealed class Result<F, S> {
  const factory Result.failure(F failure) = Failure<F, S>;
  const factory Result.success(S success) = Success<F, S>;
}

Utility Extensions #

💰 Support #

If you find this project helpful, consider sponsoring me on GitHub 💖

🙌 Contributing #

Contributions, ideas, and pull requests are welcome. Let’s make flutter_resultable better together!

🙏 Thanks #

This package is powered by the amazing freezed package. Special thanks to Remi Rousselet and contributors for their work.

Without freezed, clean and expressive sealed classes like Result wouldn't be this simple ✨

📄 License #

MIT License

🔗 Useful Links #

• Flutter Documentation
• GitHub Repository
• Pub.dev Package Page