Skill UI

Provides comprehensive guidelines and utilities for modern unit testing using Jest and React Native. Covers Test-Driven Development (TDD) workflows, Behavior-Driven Development (BDD) principles, advanced mocking strategies for modules and GraphQL hooks, and implementing reusable factory functions for props and data. Use this skill to write robust, maintainable, and highly structured unit tests.

A comprehensive guide for developers on creating and writing native modules and views using the Expo Modules API. It covers platform-specific implementation details for Swift (iOS), Kotlin (Android), and TypeScript. Use this when integrating system APIs, wrapping platform SDKs, or building complex native functionality that goes beyond standard React Native components.

Use @expo/ui to build high-fidelity, native user interfaces across iOS and Android from a single React codebase. This library renders real native UI components, such as SwiftUI on iOS and Jetpack Compose on Android. It promotes a universal component layer for cross-platform consistency, while also providing controlled access to platform-specific optimizations and drop-in replacements for existing community libraries.

This skill defines a framework-agnostic, scalable architecture pattern for React and React Native applications. It mandates feature modules, strict state separation (server vs. UI), and disciplined import rules to create predictable, maintainable, and highly scalable codebases, regardless of the chosen framework (Next.js, Remix, etc.).

This discipline establishes a portable, framework-agnostic layer for ensuring type safety at the network edge of any React or React Native application. It mandates a single, typed API client to wrap all network fetching, guaranteeing that raw wire JSON is immediately parsed into trusted, domain-specific types or standardized error objects before entering the application state. This pattern drastically reduces runtime errors and enhances code robustness.

A portable, framework-agnostic system designed for robust field-side observability in React or React Native apps. It establishes a strongly typed event taxonomy, ensures best-effort, non-blocking data fan-out across multiple analytics providers, and enforces consent gates for all telemetry data. This system complements synthetic testing by capturing real user vitals (LCP, INP, CLS) and behavioral events in production.

A comprehensive discipline for managing the write path in React or React Native applications using a query/cache layer. It codifies the full optimistic update lifecycle, ensuring that UI updates feel instantaneous, rollbacks are verbatim upon failure, and the global cache remains perfectly coherent across all components and list views. This pattern is essential for complex, highly interactive user experiences.

A framework-agnostic, builder-based SEO system designed for React and React Native-for-web applications. It centralizes site identity (title, description, OG tags) in a single source of truth, ensuring all metadata, canonical URLs, and structured data (JSON-LD, sitemap, robots.txt, RSS) are consistent, machine-readable, and automatically generated for every route.

Utilizes Expo DOM components to render web code verbatim inside a webview on native platforms, while maintaining native rendering on the web. This enables developers to integrate web-only libraries (such as charting tools, syntax highlighters, or complex CSS layouts) and incrementally migrate existing web components into a React Native application without substantial rewriting.

A comprehensive guide to best practices for building production-ready React Native and Expo applications. Covers core concepts including Expo Router navigation, state management separation, robust data fetching with TanStack Query and Zod, efficient list rendering, styling consistency, and accessing native APIs.