nextapp-devcon

A demonstration project showing how to migrate native mobile app storage to React Native using MMKV.

Overview

This project is the base for two hands-on articles about migrating user data from native mobile storage to a cross-platform React Native solution. It is a follow-up to the original article: How to Migrate User Data from Native to Cross-Platform Apps.

Article 1 — Brownfield: uses react-native-brownfield to embed React Native incrementally inside the existing native apps.

Article 2 — Greenfield: migrates to a brand-new React Native app while preserving data stored in the native apps.

Project Structure

.
├── android/        # Native Android app (SharedPreferences)
├── ios/            # Native iOS app (Keychain / UserDefaults)
├── rn/             # React Native layer (MMKV)
├── poc/ 
│   ├──             # Brownfield POC ios, android, and rn
│   └──             # Greenfield POC ios, android, and rn
└── article/
│   ├── brownfield.md  # Article 1 draft — brownfield approach
│   └── greenfield.md  # Article 2 draft — greenfield approach

Migration Path

Platform	Native Storage	Target Storage
iOS	Keychain / UserDefaults	MMKV (React Native)
Android	SharedPreferences	MMKV (React Native)

How It Works

Both articles start from the same native baseline (iOS + Android), then diverge:

Brownfield

1. Embed React Native into the existing native apps via react-native-brownfield.
2. Migrate stored data from native APIs to MMKV without replacing the native shell.

Greenfield

1. Create a fresh React Native app from scratch.
2. On first launch, read data from native storage and write it to MMKV.

References

• react-native-brownfield
• react-native-mmkv
• Original article — Cheesecake Labs