flutter-error-handling-either

Standardize Flutter repository error handling by returning Either<Failure, T> instead of throwing exceptions, mapping infrastructure errors to typed domain failures for safer state management.

Handle network errors in Flutter BLoC by mapping them to Left(Failure) at the repository boundary, then consuming the Either result with fold to branch UI state cleanly without uncaught exceptions.

Define typed domain failures in Dart by annotating union classes with @freezed, creating specific failures like UnauthorizedFailure or ApiFailure to propagate explicit error states through repositories.

Functional error handling with Either eliminates silent catches by enforcing strict layer separation; infrastructure must map errors to Left(Failure), preventing unhandled exceptions from leaking into UI components.

Use Dartz Either across repository and data source boundaries by enforcing Either<Failure, T> return types, ensuring data sources map raw errors to domain failures before propagating results downstream.

Avoid exceptions for error handling in Flutter apps when using clean architecture; returning typed failures via Either enforces explicit error handling in BLoC and prevents uncaught exceptions from disrupting UI state.