fabrik_result

A lightweight, explicit result-handling foundation for Dart and Flutter applications.

fabrik_result provides small, focused primitives for modeling success, failure, and absence of values without relying on exceptions, nulls, or heavy functional abstractions.

This package focuses on clarity, predictability, and real-world usage.

Learn more

Detailed documentation and examples are available at
fabriktool.com

Overview

The goal of fabrik_result is to make failure and absence explicit in application code.

It encourages:

  • Clear success and failure modeling
  • Explicit domain boundaries
  • Predictable control flow
  • Typed APIs without try-catch or nullable ambiguity

The package is intentionally minimal and avoids introducing a full functional programming framework.

What this package provides

Result types

Core primitives for modeling outcomes:

  • Either<L, R>
    Represents either a failure (Left) or a success (Right)

  • Option<T>
    Represents the presence (Some) or absence (None) of a value

  • Unit
    A typed replacement for void when no meaningful value is returned

Installation

dependencies:
  fabrik_result: ^1.0.0

Basic usage

Either

Use Either when an operation can fail for expected reasons and the caller must handle it explicitly.

Either<Failure, User> result = await getUser();

result.fold(
  (failure) => handleError(failure),
  (user) => handleSuccess(user),
);

Option

Use Option when a value may or may not exist, and null would be ambiguous or unsafe.

Option<User> user = findCachedUser();

user.fold(
  () => showLogin(),
  (u) => showDashboard(u),
);

Unit

Use Unit when an operation returns no meaningful data but must still be typed.

Either<Failure, Unit> result = await saveSettings();

result.fold(
  (failure) => showError(failure),
  (_) => showSuccessToast(),
);

This avoids mixing void with typed APIs and keeps function signatures consistent.

Maintainers

Libraries

fabrik_result