Best Practices Reference

Comprehensive best-practices guides for TwoMore, covering all aspects of React Native (Expo SDK 55) app development. Researched 2026-03-24 from official docs, maintainer blogs, and production community patterns.

Documents

Document	Topics	Key Actions
Performance & Memory	JS thread, re-renders, FlashList, images, bundle size, startup, Hermes, animations, memory leaks, cleanup patterns	FlashList migration, InteractionManager for heavy work, image sizing
Networking & Caching	HTTP clients, TanStack Query cache, offline-first, Supabase realtime, prefetching, pagination	Wire onlineManager, optimistic mutations, realtime cache updates
Security	Token storage, OAuth PKCE, RLS, API key protection, OTA signing, deep link validation	SecureStore for tokens, Edge Function proxy, code signing
State & Architecture	Zustand patterns, hexagonal arch, i18n, package boundaries, TypeScript strictness, code quality	Architecture fitness tests, noUncheckedIndexedAccess, reactive t()
Testing & CI/CD	Test pyramid, Jest/RNTL, Maestro E2E, error boundaries, Sentry, EAS Build/Update	GitHub Actions CI, Sentry setup, EAS Secrets migration
UI/UX & Accessibility	Component patterns, dark mode, touch targets, a11y, navigation, forms, animations	ReducedMotionConfig, a11y labels audit, hitSlop on icons
Accessibility (WCAG Test Plan)	WCAG 2.1 AA + Korean Web Accessibility Guidelines, mechanical-enforcement table, manual gaps, 5-screen TalkBack/VoiceOver test plan	Pre-launch screen-reader audit; Image accessibilityLabel + role="header" sweeps
Review Checklist	Semantic guidance reviewers must apply at PR time (the things AGENTS.md mechanical gates can't catch)	Per-PR checklist; complements AGENTS.md hard constraints
Research Methodology	Multi-dimensional research: verify what actually RUNS + ground in concrete references, not abstract principles; multi-modal sources; cross-validation	Invoked every RESEARCH phase + agent spawn; pre-conclusion checklist

Cross-Cutting Priority Actions

These items appear across multiple documents and have the highest impact:

P0 — Before Production

1. Wire onlineManager + focusManager to AppState (Networking)
2. Tokens in SecureStore, not AsyncStorage (Security)
3. RLS on every table with correct policies (Security)
4. GitHub Actions CI: npm run check on PRs (Testing)
5. Sentry crash reporting setup (Testing)
6. EAS Secrets for credentials (Testing)

P1 — Before Public Launch

7. Optimistic mutations for RSVP/scores (Networking + State)
8. noUncheckedIndexedAccess in tsconfig (Architecture)
9. Keep architecture fitness tests green for package-boundary enforcement (Architecture)
10. Per-tab error boundaries (Testing)
11. FlashList for all 20+ item lists (Performance)
12. accessibilityLabel + accessibilityRole audit (UI/UX)

P2 — Growth Phase

13. MMKV persistence for TanStack Query cache (Networking)
14. Maestro E2E for critical paths (Testing)
15. Reactive t() via Zustand for dynamic language switching (Architecture)
16. Prefetch on list item render (Networking)
17. OTA code signing (Security)