---
name: fp-ts-react
source: https://app.decimal.ai/s/fp-ts-react@2/SKILL.md
source_sha256: 493ab64bb47f
---

# Functional Programming in React

Practical patterns for React apps. No jargon, just code that works.

## Detailed Guide

Read [the detailed guide](references/detailed-guide.md) before executing this skill. It retains the complete procedure and reference material. Treat its safety, prerequisites, and validation requirements as mandatory. For focused work, load the relevant sections; for end-to-end work, read the guide completely.

## When to Use This Skill

- When building React apps with fp-ts for type-safe state management
- When handling loading/error/success states in data fetching
- When implementing form validation with error accumulation
- When using React 18/19 or Next.js 14/15 with functional patterns

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## When to Use What

| Situation | Use |
|-----------|-----|
| Value might not exist | `Option<T>` |
| Operation might fail (sync) | `Either<E, A>` |
| Async operation might fail | `TaskEither<E, A>` |
| Need loading/error/success UI | `RemoteData<E, A>` |
| Form with multiple validations | `Either` with validation applicative |
| Dependency injection | Context + `ReaderTaskEither` |
| Prevent re-renders with fp-ts | `useMemo` or `fp-ts-react-stable-hooks` |

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## Limitations
- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.