Vercel React Best Practices

3. Server-Side Performance (HIGH)

• server-auth-actions: Authenticate server actions like API routes
• server-cache-react: Use React.cache() for per-request deduplication
• server-cache-lru: Use LRU cache for cross-request caching
• server-dedup-props: Avoid duplicate serialization in RSC props
• server-serialization: Minimize data passed to client components
• server-parallel-fetching: Restructure components to parallelize fetches
• server-after-nonblocking: Use after() for non-blocking operations

4. Client-Side Data Fetching (MEDIUM-HIGH)

• client-swr-dedup: Use SWR for automatic request deduplication
• client-event-listeners: Deduplicate global event listeners
• client-passive-event-listeners: Use passive listeners for scroll
• client-localstorage-schema: Version and minimize localStorage data

5. Re-render Optimization (MEDIUM)

• rerender-defer-reads: Don't subscribe to state only used in callbacks
• rerender-memo: Extract expensive work into memoized components
• rerender-memo-with-default-value: Hoist default non-primitive props
• rerender-dependencies: Use primitive dependencies in effects
• rerender-derived-state: Subscribe to derived booleans, not raw values
• rerender-derived-state-no-effect: Derive state during render, not effects
• rerender-functional-setstate: Use functional setState for stable callbacks
• rerender-lazy-state-init: Pass function to useState for expensive values
• rerender-simple-expression-in-memo: Avoid memo for simple primitives
• rerender-move-effect-to-event: Put interaction logic in event handlers
• rerender-transitions: Use startTransition for non-urgent updates
• rerender-use-ref-transient-values: Use refs for transient frequent values

6. Rendering Performance (MEDIUM)

• rendering-animate-svg-wrapper: Animate div wrapper, not SVG element
• rendering-content-visibility: Use content-visibility for long lists
• rendering-hoist-jsx: Extract static JSX outside components
• rendering-svg-precision: Reduce SVG coordinate precision
• rendering-hydration-no-flicker: Use inline script for client-only data
• rendering-hydration-suppress-warning: Suppress expected mismatches
• rendering-activity: Use Activity component for show/hide
• rendering-conditional-render: Use ternary, not && for conditionals
• rendering-usetransition-loading: Prefer useTransition for loading state

7. JavaScript Performance (LOW-MEDIUM)

• js-batch-dom-css: Group CSS changes via classes or cssText
• js-index-maps: Build Map for repeated lookups
• js-cache-property-access: Cache object properties in loops
• js-cache-function-results: Cache function results in module-level Map
• js-cache-storage: Cache localStorage/sessionStorage reads
• js-combine-iterations: Combine multiple filter/map into one loop
• js-length-check-first: Check array length before expensive comparison
• js-early-exit: Return early from functions
• js-hoist-regexp: Hoist RegExp creation outside loops
• js-min-max-loop: Use loop for min/max instead of sort
• js-set-map-lookups: Use Set/Map for O(1) lookups
• js-tosorted-immutable: Use toSorted() for immutability

8. Advanced Patterns (LOW)

• advanced-event-handler-refs: Store event handlers in refs
• advanced-init-once: Initialize app once per app load
• advanced-use-latest: useLatest for stable callback refs