Functional Programming in React

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

Detailed Guide

Read the detailed guide 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.