Welcome to your Expo app 👋

Ding Payments — Mobile Client MVP

This repository contains the core React Native application built with Expo Router and the Soroban Smart Contract SDK for the Ding Payments network.

🛠 Prerequisites

• Node.js: v18 or later
• Package Manager: npm
• Development Target: Physical iOS or Android device (required for NFC, passkeys, and SecureStore biometrics); simulator/emulator for UI-only work

⚠️ Native Framework Limitation: This application leverages advanced hardware integrations including NFC capabilities and Passkey WebAuthn modules. These features cannot execute inside standard Expo Go. You must use an Expo Development Build (EAS Development Build) to validate NFC, passkeys, and SecureStore functionality on physical devices.

🚀 Local Development Setup

1. Clone the Repository & Fetch Dependencies

   npm install

2. Build requirements for native features

   • NFC and passkey research require an Expo development build or custom native runtime.
   • Run npx expo prebuild and npx expo run:android / npx expo run:ios for device validation.
   • Use npm run dev-client to launch a dev-client session after native dependencies are installed.

EAS Development Build

1. Install and authenticate EAS CLI

   npm install -g eas-cli
   eas login

   On first setup, link the project with eas init. Build profiles live in eas.json (development, preview, production).

2. Create a development build

   npm run dev:build:android
   # or
   npm run dev:build:ios

   Install the resulting build on a physical device (.apk on Android; iOS via internal distribution or TestFlight).

3. Start the dev client

   npm run dev-client

   This runs expo start --dev-client and connects the installed development build to Metro.

4. Native rebuild required Rebuild and reinstall the development build after changes to:

   • app.config.ts plugins, permissions, or entitlements
   • native dependencies (for example expo-dev-client, expo-secure-store, react-native-nfc-manager, react-native-passkey)

   JavaScript-only changes do not require a native rebuild.

5. Expo Go limitations Do not use Expo Go to validate NFC, passkeys, or SecureStore with biometric authentication. These flows require a development build with expo-dev-client.

6. Simulator vs physical device

   Feature	Simulator / emulator	Physical device
   General UI / routing	Yes	Yes
   NFC	No	Yes (required)
   Passkeys	Limited / unreliable	Yes (required)
   SecureStore + biometrics	Limited	Yes (required)

   Use a physical device for native capability smoke tests, including the /c05 spike page.

✅ Quality checks (CI)

CI (.github/workflows/ci-client.yml) runs the exact same npm scripts you run locally, so a green local run means a green pipeline. Run all three before opening a PR:

npm run build   # tsc --noEmit — type-checks the project
npm run lint    # expo lint (ESLint flat config + Prettier rules)
npm run format  # prettier --write . — auto-formats the repo

Helper scripts:

Script	Purpose
npm run build / npm run typecheck	TypeScript type-check (tsc --noEmit)
npm run lint	Report lint problems (expo lint)
npm run lint:fix	Auto-fix lint problems
npm run format	Format all files with Prettier
npm run format:check	Verify formatting without writing (used by CI)

Tooling config lives at the repo root: eslint.config.mjs (Expo flat config + Prettier) and .prettierrc (singleQuote, trailingComma: es5). Editors with the ESLint and Prettier extensions pick these up automatically.

C05 Spike documentation

• Passkey ADR: docs/adr-passkey-library.md
• Stellar ADR: docs/adr-stellar-sdk.md
• NFC ADR: docs/adr-nfc-library.md
• Spike PoC page: open /c05 in the app after starting the dev-client.

This is an Expo project created with create-expo-app.

Get started

1. Install dependencies

   npm install

2. Start the app

   npx expo start

   For NFC, passkeys, and SecureStore testing, use npm run dev-client (expo start --dev-client) with an installed development build—not Expo Go.

In the output, you'll find options to open the app in a

• development build
• Android emulator
• iOS simulator
• Expo Go, a limited sandbox for trying out app development with Expo

You can start developing by editing the files inside the app directory. This project uses file-based routing.

Get a fresh project

When you're ready, run:

npm run reset-project

This command will move the starter code to the app-example directory and create a blank app directory where you can start developing.

Other setup steps

• To set up ESLint for linting, run npx expo lint, or follow our guide on "Using ESLint and Prettier"
• If you'd like to set up unit testing, follow our guide on "Unit Testing with Jest"
• Learn more about the TypeScript setup in this template in our guide on "Using TypeScript"

Learn more

To learn more about developing your project with Expo, look at the following resources:

• Expo documentation: Learn fundamentals, or go into advanced topics with our guides.
• Learn Expo tutorial: Follow a step-by-step tutorial where you'll create a project that runs on Android, iOS, and the web.

Join the community

Join our community of developers creating universal apps.

• Expo on GitHub: View our open source platform and contribute.
• Discord community: Chat with Expo users and ask questions.