Sealed Unions for Dart is a package that provides a type-safe way to model sum types (also known as algebraic data types) in Dart. It enables developers to define a finite set of possible cases for a type, ensuring exhaustive pattern matching at compile time. This helps prevent runtime errors and improves code clarity when handling multiple distinct states or outcomes. The package is particularly useful in functional programming patterns within Flutter and Dart applications.
Use cases
- Handling state transitions in UI
- Modeling API responses with multiple success/failure variants
- Implementing finite state machines
- Managing error handling with typed outcomes
- Building domain models with clear case distinctions
Key features
- Compile-time safety for union cases
- Exhaustive pattern matching support
- Clean syntax for defining sealed types
- Integration with Dart's null safety
- Support for nested and recursive unions
Suitable for
- Developers using functional programming patterns
- Flutter apps requiring robust state management
- Teams prioritizing type safety and maintainability
- Projects with complex conditional logic
- Applications needing clear error and result handling
Considerations
- Requires understanding of sum types and pattern matching
- May increase initial learning curve for new team members
- Not suitable for simple data structures without variant logic
- Limited to Dart's static analysis constraints
- Best used in conjunction with linter rules for optimal safety