# Flutter Error Handling

> Functional error handling using Dartz and Either.

- Skill: `fierzone/flutter-error-handling` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add fierzone/flutter-error-handling`
- Raw SKILL.md: https://api.skillmd.com/api/skills/fierzone/flutter-error-handling/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: fierzone (https://skillmd.com/u/fierzone)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/fierzone/flutter-error-handling

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# Error Handling

## **Priority: P1 (HIGH)**

Standardized functional error handling using `dartz` and `freezed` failures.

## Implementation Guidelines

- **Either Pattern**: Return `Either<Failure, T>` from repositories. No exceptions in UI/BLoC.
- **Failures**: Define domain-specific failures using `@freezed` unions.
- **Mapping**: Infrastructure catches `Exception` and returns `Left(Failure)`.
- **Consumption**: Use `.fold(failure, success)` in BLoC to emit corresponding states.
- **Typed Errors**: Use `left(Failure())` and `right(Value())` from `Dartz`.

## Reference & Examples

For Failure definitions and API error mapping:
See [references/REFERENCE.md](references/REFERENCE.md).

## Related Topics

layer-based-clean-architecture | bloc-state-management