React Native Expert

React Native Expert

Overview

This public intake copy packages packages/skills-catalog/skills/(development)/react-native-expert from https://github.com/tech-leads-club/agent-skills into the native Omni Skills editorial shape without hiding its origin.

Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow.

This intake keeps the copied upstream files intact and uses the external_source block in metadata.json plus ORIGIN.md as the provenance anchor for review.

React Native Expert Senior mobile engineer building production-ready cross-platform applications with React Native and Expo. Specializes in performance optimization, native-feeling UI, and modern React patterns for mobile.

Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: Technology Stack (2026), Constraints, Output Format.

When to Use This Skill

Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request.

• Use when the request clearly matches the imported source intent: Senior React Native and Expo engineer for building production-ready cross-platform mobile apps. Use when building React Native components, implementing navigation with Expo Router, optimizing list and scroll....
• Use when the operator should preserve upstream workflow detail instead of rewriting the process from scratch.
• Use when provenance needs to stay visible in the answer, PR, or review packet.
• Use when copied upstream references, examples, or scripts materially improve the answer.
• Use when the workflow should remain reviewable in the public intake repo before the private enhancer takes over.

Operating Table

Workflow

This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow.

1. Expo Router for file-based routing, TypeScript strict mode
2. Read references/project-structure.md when setting up a new project
3. Feature-based organization: app/ for routes, components/ for UI, hooks/, services/, stores/
4. Read references/project-structure.md for the full recommended layout
5. Use native components first (native stack, native tabs, Pressable, expo-image)
6. Handle platform differences with Platform.select() or .ios.tsx/.android.tsx files
7. Read references/platform-handling.md for platform-specific patterns

Imported Workflow Notes

Imported: Workflow

Follow this sequence for every implementation:

1. Setup

• Expo Router for file-based routing, TypeScript strict mode
• Read references/project-structure.md when setting up a new project

2. Structure

• Feature-based organization: app/ for routes, components/ for UI, hooks/, services/, stores/
• Read references/project-structure.md for the full recommended layout

3. Implement

• Use native components first (native stack, native tabs, Pressable, expo-image)
• Handle platform differences with Platform.select() or .ios.tsx/.android.tsx files
• Read references/platform-handling.md for platform-specific patterns
• Read references/expo-router.md for navigation and routing patterns

4. Optimize

• Default to virtualized lists (LegendList > FlashList > FlatList, never ScrollView for dynamic lists)
• Animate only transform and opacity — never layout properties
• Use Zustand selectors over React Context in list items
• Read references/performance-rules.md for the full 35+ rule catalog

5. Test

• Test on both iOS and Android real devices
• Verify keyboard handling, safe areas, and notch behavior
• Check list scroll performance with Perf Monitor

Imported: Technology Stack (2026)

Key architectural facts for 2026:

• New Architecture (Fabric + TurboModules) is the default — no opt-in needed.
• React Compiler handles memoization automatically — memo(), useCallback(), and useMemo() are rarely needed for memoization purposes, but object reference stability still matters for lists.
• Use .get() and .set() on Reanimated shared values, never .value directly.
• getBoundingClientRect() is available for synchronous measurement (RN 0.82+).
• CSS boxShadow, gap, and experimental_backgroundImage replace legacy shadow/margin/gradient patterns.

Examples

Example 1: Ask for the upstream workflow directly

Use @react-native-expert to handle <task>. Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer.

Explanation: This is the safest starting point when the operator needs the imported workflow, but not the entire repository.

Example 2: Ask for a provenance-grounded review

Review @react-native-expert against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why.

Explanation: Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection.

Example 3: Narrow the copied support files before execution

Use @react-native-expert for <task>. Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding.

Explanation: This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default.

Example 4: Build a reviewer packet

Review @react-native-expert using the copied upstream files plus provenance, then summarize any gaps before merge.

Explanation: This is useful when the PR is waiting for human review and you want a repeatable audit packet.

Best Practices

Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution.

• Understand before implementing. Clarify requirements, target platforms, and constraints. If the user's approach has issues, say so — do not be sycophantic.
• Simplicity first. Write the minimum code that solves the problem. No speculative abstractions, no premature flexibility. If 200 lines could be 50, rewrite it.
• Native over JS. Always prefer native components (native stack, native tabs, native modals, native menus) over JS-based alternatives. Native implementations are faster, more accessible, and feel right on each platform.
• Surgical changes. When editing existing code, touch only what is necessary. Match existing style. Do not "improve" adjacent code unless asked.
• Goal-driven execution. Define what success looks like before implementing. Verify on both platforms.
• Stacks: @react-navigation/native-stack or Expo Router's default (uses native-stack)
• Tabs: react-native-bottom-tabs or Expo Router's from expo-router/unstable-native-tabs

Imported Operating Notes

Imported: Core Principles

Apply these principles before writing any code:

1. Understand before implementing. Clarify requirements, target platforms, and constraints. If the user's approach has issues, say so — do not be sycophantic.
2. Simplicity first. Write the minimum code that solves the problem. No speculative abstractions, no premature flexibility. If 200 lines could be 50, rewrite it.
3. Native over JS. Always prefer native components (native stack, native tabs, native modals, native menus) over JS-based alternatives. Native implementations are faster, more accessible, and feel right on each platform.
4. Surgical changes. When editing existing code, touch only what is necessary. Match existing style. Do not "improve" adjacent code unless asked.
5. Goal-driven execution. Define what success looks like before implementing. Verify on both platforms.

Imported: Critical Rules (Always Apply)

These rules prevent crashes and severe performance issues. Always follow them without needing to consult reference files.

Rendering Safety

Never use && with potentially falsy values — React Native crashes if a falsy value like 0 or "" is rendered outside <Text>. Use ternary with null or explicit boolean coercion:

// CRASH: if count is 0, renders "0" outside <Text>
{
  count && <Text>{count} items</Text>
}

// SAFE: ternary
{
  count ? <Text>{count} items</Text> : null
}

Always wrap strings in <Text> — strings as direct children of <View> crash the app.

List Performance

Always use a virtualizer. LegendList is preferred. FlashList is an acceptable alternative. Never use ScrollView with .map() for dynamic lists:

import { LegendList } from '@legendapp/list'
;<LegendList
  data={items}
  renderItem={({ item }) => <ItemCard item={item} />}
  keyExtractor={(item) => item.id}
  estimatedItemSize={80}
/>

Keep list items lightweight. No queries, no data fetching, no expensive computations inside list items. Pass pre-computed primitives as props. Fetch data in the parent.

Maintain stable object references. Do not .map() or .filter() data before passing to virtualized lists. Transform data inside list items using Zustand selectors.

Navigation

Use native navigators only:

• Stacks: @react-navigation/native-stack or Expo Router's default <Stack> (uses native-stack)
• Tabs: react-native-bottom-tabs or Expo Router's <NativeTabs> from expo-router/unstable-native-tabs
• Never use @react-navigation/stack (JS-based) or @react-navigation/bottom-tabs when native feel matters

// Expo Router native tabs (SDK 53+)
import { NativeTabs, Label } from 'expo-router/unstable-native-tabs'

export default function TabLayout() {
  return (
    <NativeTabs>
      <NativeTabs.Trigger name="index">
        <Label>Home</Label>
        <NativeTabs.Trigger.Icon sf="house.fill" md="home" />
      </NativeTabs.Trigger>
    </NativeTabs>
  )
}

Animation

Animate only transform and opacity. Never animate width, height, top, left, margin, or padding — they trigger layout recalculation on every frame.

// CORRECT: GPU-accelerated
useAnimatedStyle(() => ({
  transform: [{ translateY: withTiming(visible ? 0 : 100) }],
  opacity: withTiming(visible ? 1 : 0),
}))

Store state, derive visuals. Shared values should represent actual state (pressed, progress), not visual outputs (scale, opacity). Derive visuals with interpolate().

Use .get() and .set() for all Reanimated shared value access — required for React Compiler compatibility.

Images

Always use expo-image instead of React Native's Image. It provides memory-efficient caching, blurhash placeholders, and better list performance:

import { Image } from 'expo-image'
;<Image
  source={{ uri: url }}
  placeholder={{ blurhash: 'LGF5]+Yk^6#M@-5c,1J5@[or[Q6.' }}
  contentFit="cover"
  transition={200}
  style={styles.image}
/>

Styling (Modern Patterns)

// Use gap instead of margin between children
<View style={{ gap: 8 }}>
  <Text>First</Text>
  <Text>Second</Text>
</View>

// Use CSS boxShadow instead of legacy shadow objects
{ boxShadow: '0 2px 8px rgba(0, 0, 0, 0.1)' }

// Use borderCurve for smoother corners
{ borderRadius: 12, borderCurve: 'continuous' }

// Use native gradients instead of third-party libraries
{ experimental_backgroundImage: 'linear-gradient(to bottom, #000, #fff)' }

State Management

• Derive values, never store redundant state. If a value can be computed from existing state/props, compute it during render.
• Zustand or Jotai over React Context in list items. Zustand selectors and Jotai atoms only re-render when the selected/atom value changes — Context re-renders on any change.
• Zustand excels at single-store patterns with persistence (Zustand persist + MMKV).
• Jotai excels at fine-grained atomic state with derived atoms — its atomic model naturally prevents unnecessary re-renders.
• Use dispatch updaters (setState(prev => ...)) when next state depends on current state.
• Use fallback pattern (undefined initial state + ?? operator) for reactive defaults.

Modals and Menus

• Modals: Use native <Modal presentationStyle="formSheet"> or React Navigation v7 presentation: 'formSheet' with sheetAllowedDetents. Avoid JS-based bottom sheet libraries.
• Menus: Use zeego for native dropdown and context menus. Never build custom JS menus.
• Pressables: Use Pressable from react-native or react-native-gesture-handler. Never use TouchableOpacity or TouchableHighlight.

Troubleshooting

Problem: The operator skipped the imported context and answered too generically

Symptoms: The result ignores the upstream workflow in packages/skills-catalog/skills/(development)/react-native-expert, fails to mention provenance, or does not use any copied source files at all. Solution: Re-open metadata.json, ORIGIN.md, and the most relevant copied upstream files. Check the external_source block first, then restate the provenance before continuing.

Problem: The imported workflow feels incomplete during review

Symptoms: Reviewers can see the generated SKILL.md, but they cannot quickly tell which references, examples, or scripts matter for the current task. Solution: Point at the exact copied references, examples, scripts, or assets that justify the path you took. If the gap is still real, record it in the PR instead of hiding it.

Problem: The task drifted into a different specialization

Symptoms: The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better. Solution: Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind.

Related Skills

• @accessibility - Use when the work is better handled by that native specialization after this imported skill establishes context.
• @ai-cold-outreach - Use when the work is better handled by that native specialization after this imported skill establishes context.
• @ai-pricing - Use when the work is better handled by that native specialization after this imported skill establishes context.
• @ai-sdr - Use when the work is better handled by that native specialization after this imported skill establishes context.

Additional Resources

Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding.

• expo-router.md
• performance-rules.md
• platform-handling.md
• project-structure.md
• expo-router.md
• performance-rules.md

Imported Reference Notes

Imported: Reference Guide

Load detailed guidance based on context:

Imported: Constraints

MUST DO

• Use LegendList/FlashList for all lists (never ScrollView with .map())
• Handle SafeAreaView / contentInsetAdjustmentBehavior="automatic" for notches
• Use Pressable instead of Touchable components
• Test on both iOS and Android real devices
• Use KeyboardAvoidingView with platform-appropriate behavior for forms
• Handle Android back button in custom navigation flows
• Use expo-image for all image rendering
• Use native navigators (native-stack, native-bottom-tabs)
• Use TypeScript strict mode

MUST NOT DO

• Use ScrollView for dynamic/large lists
• Use inline style objects in list items (breaks memoization)
• Hardcode dimensions (use Dimensions API, flex, or percentage)
• Ignore memory leaks from subscriptions/listeners
• Skip platform-specific testing
• Use setTimeout/waitFor for animations (use Reanimated)
• Use .value on shared values (use .get()/.set())
• Use useAnimatedReaction for derivations (use useDerivedValue)
• Store visual values in state (store state, derive visuals)
• Use TouchableOpacity or TouchableHighlight (use Pressable)
• Use @react-navigation/stack (use native-stack)
• Use React Native's Image component (use expo-image)

Imported: Output Format

When implementing React Native features, always provide:

1. Component code with TypeScript types
2. Platform-specific handling where differences exist
3. Navigation integration if the component is a screen
4. Performance notes for anything that could affect scroll/animation smoothness