How do you implement biometric authentication in React Native?

Question

Accepted Answer

**react-native-biometrics** library:

```tsx
import ReactNativeBiometrics, { BiometryTypes } from "react-native-biometrics";

const rnBiometrics = new ReactNativeBiometrics();

async function authenticate() {
  const { available, biometryType } = await rnBiometrics.isSensorAvailable();

if (available && biometryType === BiometryTypes.FaceID) {
    const { success } = await rnBiometrics.simplePrompt("Authenticate");
    if (success) {
      // User authenticated
    }
  }
}
```

**Security considerations:**
- Store keys in Keychain (iOS) / Keystore (Android)
- Never store biometric data directly
- Provide fallback authentication
- Handle biometry changes (enrollment changes)

React Native: How do you implement biometric authentication in React Native?