React Native 0.79.x to 0.83.x Migration Assistant

Description

Expert guidance for migrating React Native projects from version 0.79.x to 0.83.x. This skill provides automated detection of breaking changes, step-by-step migration assistance, code fixes, and validation specific to this version upgrade.

When to Use

Use this skill when:

• Upgrading React Native from 0.79.x to 0.83.x (or minor/patch versions within these ranges)
• Encountering build errors after RN upgrade
• Updating Android native modules for RN 0.83.x compatibility
• Migrating MMKV storage code
• Refactoring MainApplication.kt for new architecture
• Validating migration completeness

Triggers

• "migrate react native to 0.83"
• "upgrade from RN 0.79"
• "fix RN 0.83 build errors"
• "update native modules for RN 0.83"
• "MainApplication.kt errors after upgrade"
• "MMKV migration"

---

Migration Workflow

When invoked, follow this systematic approach:

Phase 1: Pre-Migration Analysis

1. Detect Current Version

   grep "react-native" package.json

2. Scan for Breaking Change Patterns

   • Android native modules using currentActivity
   • Android modules with onNewIntent(Intent?)
   • MainApplication.kt structure
   • MMKV usage (new MMKV(), .delete())
   • Dependency versions

3. Create Migration Checklist
   Use TodoWrite to track:

   • Dependency updates
   • Android native module fixes
   • MainApplication.kt refactoring
   • MMKV API updates
   • Clean build
   • Testing

Phase 2: Automated Detection

Run parallel searches to find affected code:

# Find native modules with currentActivity
grep -r "currentActivity" android/app/src/main/java

# Find onNewIntent with nullable Intent
grep -r "onNewIntent(intent: Intent?)" android/app/src/main/java

# Find MMKV usage
grep -r "new MMKV\|storage\.delete" src/

# Find MainApplication
find android/app/src/main/java -name "MainApplication.kt"

Phase 3: Guided Fixes

For each breaking change detected, provide:

3.1 Android Native Module - currentActivity Fix

Detection Pattern:

val activity = currentActivity
// or
val activity: Activity? = currentActivity

Required Fix:

val activity: Activity? = reactApplicationContext.currentActivity

Action:

• Use Edit tool to replace pattern
• IMPORTANT: Add import android.app.Activity at the top of the file if not present
• Files affected: *Module.kt
• In some modules, you may need to explicitly add the type annotation: val activity: Activity? = ...

3.2 Android Native Module - onNewIntent Fix

Detection Pattern:

override fun onNewIntent(intent: Intent?) {

Required Fix:

override fun onNewIntent(intent: Intent) {
    // Not needed for this implementation
}

Action:

• Use Edit tool to remove ? nullable operator
• Update implementation to handle non-null Intent
• If the method body was empty or had = Unit, replace with a proper implementation or comment

3.3 MainApplication.kt Refactoring

Detection: Check if file contains ReactNativeHost or DefaultReactNativeHost

Required Changes:

1. Remove reactNativeHost property
2. Update reactHost to use lazy initialization
3. Replace SoLoader.init() with loadReactNative(this)
4. Update imports

Template:

import com.facebook.react.PackageList
import com.facebook.react.ReactApplication
import com.facebook.react.ReactHost
import com.facebook.react.ReactNativeApplicationEntryPoint.loadReactNative
import com.facebook.react.defaults.DefaultReactHost.getDefaultReactHost

class MainApplication : Application(), ReactApplication {

  override val reactHost: ReactHost by lazy {
    getDefaultReactHost(
      context = applicationContext,
      packageList =
        PackageList(this).packages.apply {
          // Add custom packages
          add(YourCustomPackage())
          // Note: RazorpayPackage() may need to be replaced with RazorpayCustomPackage()
          // depending on your razorpay-react-native version
        },
    )
  }

  override fun onCreate() {
    super.onCreate()
    loadReactNative(this)
    // Your custom initialization
  }
}

3.4 MMKV Storage Migration

Detection Patterns:

import { MMKV } from 'react-native-mmkv'
new MMKV({
storage.delete(key)

Required Fixes:

import { createMMKV } from 'react-native-mmkv'
createMMKV({
storage.remove(key)

Action:

• Use Edit tool for each occurrence
• Typically affects: src/utils/storage.ts

Phase 4: Dependency Updates

Provide exact npm commands:

# Core dependencies
npm install react@19.2.0 react-native@0.83.0

# Updated dependencies with verified versions
npm install react-native-mmkv@4.1.0
npm install @react-native-async-storage/async-storage@2.2.0
npm install react-native-gesture-handler@2.30.0
npm install react-native-reanimated@4.2.1
npm install react-native-safe-area-context@5.6.2
npm install react-native-svg@15.15.1
npm install react-native-screens@4.19.0
npm install react-native-svg-transformer@1.5.2
npm install react-native-customui@2.2.6
npm install react-native-device-info@15.0.1
npm install react-native-nitro-modules@0.31.10
npm install react-native-nitro-sound@0.2.10
npm install react-native-otp-entry@1.8.5
npm install react-native-worklets@0.7.1

# Updated Firebase dependencies (if using)
npm install @react-native-firebase/app@23.7.0
npm install @react-native-firebase/analytics@23.7.0
npm install @react-native-firebase/auth@23.7.0
npm install @react-native-firebase/crashlytics@23.7.0
npm install @react-native-firebase/installations@23.7.0
npm install @react-native-firebase/messaging@23.7.0

# Updated navigation dependencies (if using)
npm install @react-navigation/native@7.1.26
npm install @react-navigation/bottom-tabs@7.9.0
npm install @react-navigation/native-stack@7.9.0
npm install @react-navigation/stack@7.6.13

# Other updated dependencies
npm install @react-native-google-signin/google-signin@16.0.0
npm install @tanstack/react-query@5.90.12
npm install react-native-video@6.18.0
npm install socket.io-client@4.8.3

# Dev dependencies
npm install --save-dev @react-native-community/cli@20.0.0
npm install --save-dev @react-native-community/cli-platform-android@20.0.0
npm install --save-dev @react-native-community/cli-platform-ios@20.0.0
npm install --save-dev @react-native/babel-preset@0.83.0
npm install --save-dev @react-native/metro-config@0.83.0
npm install --save-dev @types/react@19.2.0
npm install --save-dev react-test-renderer@19.2.0
npm install --save-dev jest@29.2.1

Phase 4.1: Node.js Version Check

React Native 0.83.0 requires Node.js >= 20. Verify your Node version:

node --version  # Should be v20.x.x or higher

If you need to upgrade Node.js, use nvm or your preferred Node version manager.

Phase 5: Clean Build

Execute build cleanup:

# Clean node_modules
rm -rf node_modules package-lock.json
npm install

# Clean Android
cd android && ./gradlew clean && cd ..

# Clean iOS (if applicable)
cd ios && rm -rf Pods Podfile.lock && pod install && cd ..

# Reset Metro cache
npx react-native start --reset-cache

Phase 6: Validation

Run validation checks:

1. Build Validation

   # Android
   npm run android
   
   # iOS
   npm run ios

2. Code Pattern Validation

   # Should return 0 results:
   grep -r "currentActivity[^.]" android/app/src/main/java
   grep -r "Intent?" android/app/src/main/java
   grep -r "new MMKV" src/
   grep -r "storage\.delete" src/
   grep -r "ReactNativeHost" android/
   grep -r "SoLoader\.init" android/

3. Functional Testing Checklist

   • App launches without crashes
   • Storage read/write works (MMKV)
   • Native modules function correctly
   • Navigation works
   • Third-party integrations work
   • No console warnings

Phase 7: Documentation

After successful migration:

1. Update CHANGELOG (if exists)
2. Document custom changes (if any project-specific modifications were needed)
3. Reference main migration guide: docs/solutions/migration-guides/react-native-0.79.x-to-0.83.x.md

---

Common Issues & Solutions

Issue: "Cannot find symbol: currentActivity"

Quick Fix:

// Replace all occurrences in native modules
currentActivity → reactApplicationContext.currentActivity

Issue: "Type mismatch: onNewIntent"

Quick Fix:

// Remove nullable operator
override fun onNewIntent(intent: Intent?) { }
↓
override fun onNewIntent(intent: Intent) { }

Issue: "Property 'delete' does not exist on type 'MMKV'"

Quick Fix:

storage.delete(key) → storage.remove(key)

Issue: "Cannot resolve symbol 'ReactNativeHost'"

Quick Fix:
Refactor entire MainApplication.kt using the template in Phase 3.3

---

Files Typically Modified

Track these files during migration:

Android Native Code:

• android/app/src/main/java/*/MainApplication.kt (major refactoring)
• android/app/src/main/java/*/*Module.kt (all custom modules)

JavaScript/TypeScript:

• src/utils/storage.ts (MMKV changes)
• Any file directly using MMKV

Configuration:

• package.json (dependency versions)
• package-lock.json (regenerated)

---

Rollback Strategy

If migration fails:

# Revert all changes
git checkout HEAD -- package.json package-lock.json android/ ios/

# Clean install
rm -rf node_modules
npm install

# Clean build
cd android && ./gradlew clean && cd ..
npx react-native start --reset-cache

---

Success Criteria

Migration is complete when:

✅ All breaking change patterns have been fixed
✅ App builds successfully on Android
✅ App builds successfully on iOS
✅ No runtime crashes on launch
✅ Storage operations work correctly
✅ All native modules function properly
✅ No deprecated API warnings in console
✅ Tests pass

---

Additional Resources

Reference the comprehensive migration guide:

• Location: docs/solutions/migration-guides/react-native-0.79.x-to-0.83.x.md
• Contains: Detailed explanations, full code examples, testing strategy

External resources:

• React Native Upgrade Helper
• React Native 0.83 Release Notes
• MMKV v4 Migration

---

Execution Strategy

When user invokes this skill:

1. Assess current state - Check if already on 0.83.x or migrating
2. Create todo list - Track all migration phases
3. Run automated detection - Find all breaking change patterns
4. Present findings - Show user what needs to be fixed
5. Execute fixes - Apply changes systematically with user approval
6. Validate - Run all validation checks
7. Document - Update any project-specific documentation

Always use TodoWrite to track progress and keep user informed of migration status.

---

Version Scope

This skill is optimized for:

• Source versions: React Native 0.79.0 through 0.79.x
• Target versions: React Native 0.83.0 through 0.83.x
• Compatibility: Minor and patch versions within these ranges

For migrations to/from other major versions, refer to official React Native upgrade guides.