provectus React Best Practices
Comprehensive performance optimization guide for React applications. Contains 37 rules across 7 categories, prioritized by impact.
Rule Categories by Priority
| Priority | Category | Impact | Prefix |
|---|---|---|---|
| 1 | Eliminating Waterfalls | CRITICAL | async- |
| 2 | Bundle Size Optimization | CRITICAL | bundle- |
| 3 | Client-Side Data Fetching | MEDIUM-HIGH | client- |
| 4 | Re-render Optimization | MEDIUM | rerender- |
| 5 | Rendering Performance | MEDIUM | rendering- |
| 6 | JavaScript Performance | LOW-MEDIUM | js- |
| 7 | Advanced Patterns | LOW | advanced- |
Quick Reference
1. Eliminating Waterfalls (CRITICAL)
async-defer-await- Move await into branches where actually usedasync-parallel- Use Promise.all()/allSettled() for independent operations
2. Bundle Size Optimization (CRITICAL)
bundle-dynamic-imports- React.lazy() for heavy componentsbundle-defer-third-party- Load analytics/logging on demandbundle-conditional- Load modules only when feature is activatedbundle-preload- Preload on hover/focus for perceived speed
3. Client-Side Data Fetching (MEDIUM-HIGH)
client-query-dedup- Use TanStack Query for automatic request deduplicationclient-event-listeners- Deduplicate global event listenersclient-passive-event-listeners- Use passive listeners for scroll performanceclient-localstorage-schema- Version and minimize localStorage data
4. Re-render Optimization (MEDIUM)
rerender-defer-reads- Don't subscribe to state only used in callbacksrerender-memo- Extract expensive work into memoized componentsrerender-dependencies- Use primitive dependencies in effectsrerender-derived-state- Subscribe to derived booleans, not raw valuesrerender-functional-setstate- Use functional setState for stable callbacksrerender-lazy-state-init- Pass function to useState for expensive valuesrerender-transitions- Use startTransition for non-urgent updates
5. Rendering Performance (MEDIUM)
rendering-animate-svg-wrapper- Animate div wrapper, not SVG elementrendering-content-visibility- Use content-visibility for long listsrendering-hoist-jsx- Extract static JSX outside componentsrendering-svg-precision- Reduce SVG coordinate precisionrendering-activity- Use Activity component for show/hiderendering-conditional-render- Use ternary, not && for conditionals
6. JavaScript Performance (LOW-MEDIUM)
js-batch-dom-css- Group CSS changes via classes or cssTextjs-index-maps- Build Map for repeated lookupsjs-cache-property-access- Cache object properties in loopsjs-cache-function-results- Cache function results in module-level Mapjs-cache-storage- Cache localStorage/sessionStorage readsjs-combine-iterations- Combine multiple filter/map into one loopjs-length-check-first- Check array length before expensive comparisonjs-early-exit- Return early from functionsjs-hoist-regexp- Hoist RegExp creation outside loopsjs-min-max-loop- Use loop for min/max instead of sortjs-set-map-lookups- Use Set/Map for O(1) lookupsjs-tosorted-immutable- Use toSorted() for immutability
7. Advanced Patterns (LOW)
advanced-event-handler-refs- Store event handlers in refsadvanced-use-latest- useLatest for stable callback refs
How to Use
Each rule file in references/ contains: explanation, incorrect/correct code examples, and context. Read individual files as needed.