Core Functions

isSensorAvailable()

Checks if biometric authentication is available on the device.

const isSensorAvailable = (options?: {
  biometricStrength?: BiometricStrength;  // Android only — the strength class to check for (defaults to Strong)
}): Promise<BiometricSensorInfo> => {
};

type BiometricSensorInfo = {
  available: boolean;        // Whether biometric auth is available
  biometryType?: 'Biometrics' | 'FaceID' | 'TouchID' | 'None' | 'Unknown';
  isDeviceSecure: boolean;   // Whether the device has a passcode/PIN/password set
  error?: string;            // Error message if not available
  errorCode?: string;        // Error code if not available (platform-specific)
  fallbackUsed?: boolean;
  biometricStrength?: BiometricStrength;
}

Platform Notes:

• biometricStrength is Android-only; iOS ignores it
• Android reports 'Biometrics' for available sensors; 'FaceID'/'TouchID' are iOS values
• errorCode is available on both iOS and Android platforms
• iOS returns specific error codes like "BiometryNotAvailable", "BiometryNotEnrolled", etc.
• Android returns descriptive error codes like "BiometricErrorNoHardware", "BiometricErrorNoneEnrolled", etc.
• The error property provides human-readable messages on both platforms

simplePrompt()

Performs basic biometric authentication with a custom message.

const simplePrompt = (
  promptMessage: string,
  options?: { biometricStrength?: BiometricStrength }  // Android only
): Promise<BiometricAuthResult> => {
};

Parameters:

• promptMessage (string): Message to display to the user
• options.biometricStrength (optional, Android only): BiometricStrength.Strong or BiometricStrength.Weak

Returns: Promise<BiometricAuthResult> — check result.success for the outcome

authenticateWithOptions()

Enhanced authentication with customizable options and detailed results.

const authenticateWithOptions = (options: BiometricAuthOptions): Promise<BiometricAuthResult> => {
};

type BiometricAuthOptions = {
  title?: string;                    // Dialog title
  subtitle?: string;                 // Dialog subtitle
  description?: string;              // Additional description
  cancelLabel?: string;              // Cancel button text
  fallbackLabel?: string;            // Fallback button text
  allowDeviceCredentials?: boolean;  // Allow PIN/password fallback
  disableDeviceFallback?: boolean;   // Disable fallback options
  biometricStrength?: BiometricStrength;  // Android only
  returnAuthType?: boolean;          // Include authType in result (see AuthType enum)
}

type BiometricAuthResult = {
  success: boolean;          // Authentication result
  error?: string;            // Error message if failed
  errorCode?: string;        // Error code if failed
  fallbackUsed?: boolean;    // Whether a fallback method was used
  authType?: AuthType;       // How the user authenticated (only when returnAuthType is true)
}