React 19 + Vite Guide

Comprehensive guidelines for building React 19 SPA applications with Vite. Combines composition patterns, performance optimization, and web interface best practices into a single reference optimized for AI agent workflows.

Tech Stack

• React 19 — use(), ref as prop, React Compiler support
• Vite — React.lazy() + dynamic import(), env variables, HMR
• TypeScript — strict mode recommended
• Pure SPA (CSR) — no SSR, no hydration concerns

Capability Index

1. Composition Patterns (references/composition-patterns.md)

Component architecture and state management patterns for scalable React apps.

Priority	Category	Impact
1	Component Architecture	HIGH
2	State Management	MEDIUM
3	Implementation Patterns	MEDIUM
4	React 19 APIs	MEDIUM

Key topics:

• Boolean prop proliferation vs composition alternatives
• Compound components with shared context
• State management decoupled from UI via providers
• Generic context interfaces (state/actions/meta)
• State lifted into providers for sibling access
• Explicit component variants vs boolean modes
• Children vs render props
• React 19: use() replaces useContext(), ref as regular prop

2. Performance Optimization (references/performance-optimization.md)

Performance optimization patterns adapted for Vite + React 19 SPA. Next.js-specific patterns removed; Vite equivalents provided.

Priority	Category	Impact
1	Async Optimization	CRITICAL
2	Bundle Size	CRITICAL
3	Client-Side Data Fetching	MEDIUM-HIGH
4	Re-render Optimization	MEDIUM
5	Rendering Performance	MEDIUM
6	JavaScript Performance	LOW-MEDIUM
7	Advanced Patterns	LOW

Key topics:

• Promise.all() and dependency-based parallelization
• React.lazy() + Suspense for code splitting (Vite)
• Barrel file import cost and direct imports
• Hover/focus preloading for perceived speed
• SWR for client-side data deduplication
• Functional setState, lazy state initialization
• useTransition for non-urgent updates
• content-visibility: auto for long lists
• useRef for transient values
• Module-level caching patterns

3. Web Interface (references/web-interface.md)

UI/UX patterns for accessibility, forms, animation, performance, and content quality.

Category	Focus
Accessibility	ARIA, semantic HTML, keyboard handlers
Focus States	focus-visible, no bare outline-none
Forms	autocomplete, correct type, paste allowed
Animation	prefers-reduced-motion, compositor-only props
Typography	Ellipsis, curly quotes, tabular-nums
Content Handling	Truncation, empty states, long content
Images	Explicit dimensions, lazy loading
Performance	Virtualization, no layout reads in render
Navigation & State	URL reflects state, deep-linkable UI
Touch & Interaction	touch-action, overscroll-behavior
Dark Mode	color-scheme, theme-color meta
Locale & i18n	Intl.DateTimeFormat, Intl.NumberFormat

4. Vite-Specific Patterns (references/vite-specific.md)

Vite-specific configuration, conventions, and optimization patterns.

Key topics:

• Dynamic imports and code splitting with Vite
• Environment variables (import.meta.env)
• Vite plugin ecosystem (React SWC/Babel)
• Build optimization (manualChunks, rollupOptions)
• Alias and path resolution
• CSS Modules / Tailwind CSS integration