Onchain

A modern crypto asset management app built with React Native. This project features:

• SwiftUI-based Fabric Component: A high-performance native UI component written in SwiftUI and integrated via React Native's Fabric architecture.
• TurboModule: A custom TurboModule bridges communication between native code and React Native, enabling fast, type-safe, and flexible data exchange.
• TypeScript-first: All business logic, utilities, and types are written in TypeScript for safety and maintainability.
• Modular Structure: UI components, business logic, and types are separated for easy testing and reuse.
• Unit Testing: Core logic (filtering, sorting, formatting) is covered by unit tests.

Features

• Crypto asset overview with real-time USD/HKD conversion
• Sort and filter assets by value, name, or percentage change
• Pull-to-refresh and skeleton loading states
• Modern, accessible UI
• Native currency picker (SwiftUI Fabric component)
• Native-to-JS communication via TurboModule

Project Structure

src/
  screens/
    AssetScreen/
      components/         # Reusable UI components (AssetItem, SortButton, etc.)
      utils.ts            # Pure functions (filter, sort, format, etc.)
      types.ts            # TypeScript type definitions
      index.tsx           # Main screen logic
      Currency.json       # Asset data
      Fiat_rate_hkd.json  # HKD rates
      Fiat_rate_usd.json  # USD rates
    ...
  ...
specs/
  NativeStoreValueManager.ts # TurboModule interface
  CurrencyPickerNativeComponent.swift # SwiftUI Fabric component

Native Integration

SwiftUI Fabric Component

• The currency picker is implemented in SwiftUI and exposed to React Native via the new Fabric renderer for best performance and smooth animations.

TurboModule

• A custom TurboModule (NativeStoreValueManager) is used for fast, type-safe communication between native (Swift/ObjC) and React Native (TypeScript).
• Used for currency selection and other native events.

Testing

• Pure functions (filterAssets, sortAssets, formatCurrency, etc.) are unit tested in utils.test.ts.
• Run tests with:

  npm test
  # or
  yarn test

Running the App

1. Install dependencies:

   yarn install
   # or
   npm install

2. Start Metro:

   yarn start
   # or
   npm start

3. Run on iOS:

   yarn ios
   # or
   npm run ios

4. Run on Android:

   yarn android
   # or
   npm run android

Notes

• Make sure you have the required native build environment for iOS (Xcode) and Android (Android Studio/SDK).
• The SwiftUI Fabric component and TurboModule require a modern React Native version (0.70+ recommended).

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Onchain is a showcase of modern React Native + Native (SwiftUI) integration, with a focus on clean architecture, type safety, and great user experience.

Getting Started

Note: Make sure you have completed the Set Up Your Environment guide before proceeding.

Step 1: Start Metro

First, you will need to run Metro, the JavaScript build tool for React Native.

To start the Metro dev server, run the following command from the root of your React Native project:

# Using npm
npm start

# OR using Yarn
yarn start

Step 2: Build and run your app

With Metro running, open a new terminal window/pane from the root of your React Native project, and use one of the following commands to build and run your Android or iOS app:

Android

# Using npm
npm run android

# OR using Yarn
yarn android

iOS

For iOS, remember to install CocoaPods dependencies (this only needs to be run on first clone or after updating native deps).

The first time you create a new project, run the Ruby bundler to install CocoaPods itself:

bundle install

Then, and every time you update your native dependencies, run:

bundle exec pod install

For more information, please visit CocoaPods Getting Started guide.

# Using npm
npm run ios

# OR using Yarn
yarn ios

If everything is set up correctly, you should see your new app running in the Android Emulator, iOS Simulator, or your connected device.

This is one way to run your app — you can also build it directly from Android Studio or Xcode.

Step 3: Modify your app

Now that you have successfully run the app, let's make changes!

Open App.tsx in your text editor of choice and make some changes. When you save, your app will automatically update and reflect these changes — this is powered by Fast Refresh.

When you want to forcefully reload, for example to reset the state of your app, you can perform a full reload:

• Android: Press the R key twice or select "Reload" from the Dev Menu, accessed via Ctrl + M (Windows/Linux) or Cmd ⌘ + M (macOS).
• iOS: Press R in iOS Simulator.

Congratulations! 🎉

You've successfully run and modified your React Native App. 🥳

Now what?

• If you want to add this new React Native code to an existing application, check out the Integration guide.
• If you're curious to learn more about React Native, check out the docs.

Troubleshooting

If you're having issues getting the above steps to work, see the Troubleshooting page.

Learn More

To learn more about React Native, take a look at the following resources:

• React Native Website - learn more about React Native.
• Getting Started - an overview of React Native and how setup your environment.
• Learn the Basics - a guided tour of the React Native basics.
• Blog - read the latest official React Native Blog posts.
• @facebook/react-native - the Open Source; GitHub repository for React Native.