React 19 Development

React 19 component patterns, hooks, and testing methodology for production applications. This covers the component and composition layer — component design, hooks, state management, error handling within components, and testing strategies.

For React Router loaders, actions, mutations, and data patterns, see /react-router. For TypeScript strictness, testing, and build tooling, see /typescript. For component design, form UX, and accessibility, see /ux-design. For CSS and responsive patterns, see /css-responsive.