Add getSupportedBiometryType

KeychainExample/app.js

@@ -16,8 +16,15 @@ export default class KeychainExample extends Component {
     username: '',
     password: '',
     status: '',
+    biometryType: null,
   };
 
+  componentDidMount() {
+    Keychain.getSupportedBiometryType().then(biometryType => {
+      this.setState({ biometryType });
+    });
+  }
+
   save() {
     Keychain.setGenericPassword(this.state.username, this.state.password)
       .then(() => {
@@ -91,6 +98,11 @@ export default class KeychainExample extends Component {
           {!!this.state.status && (
             <Text style={styles.status}>{this.state.status}</Text>
           )}
+          {!!this.state.biometryType && (
+            <Text style={styles.biometryType}>
+              Supported biometry: {this.state.biometryType}
+            </Text>
+          )}
           <View style={styles.buttons}>
             <TouchableHighlight
               onPress={() => this.save()}
@@ -160,6 +172,11 @@ const styles = StyleSheet.create({
     fontSize: 12,
     marginTop: 15,
   },
+  biometryType: {
+    color: '#333',
+    fontSize: 12,
+    marginTop: 15,
+  },
   buttons: {
     flexDirection: 'row',
     justifyContent: 'space-between',

RNKeychainManager/RNKeychainManager.m

@@ -178,6 +178,23 @@ RCT_EXPORT_METHOD(canCheckAuthentication:(NSDictionary *)options resolver:(RCTPr
     }
 }
 
+RCT_EXPORT_METHOD(getSupportedBiometryType:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject)
+{
+  NSError *aerr = nil;
+  LAContext *context = [LAContext new];
+  BOOL canBeProtected = [context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&aerr];
+
+  if (!aerr && canBeProtected) {
+    if (@available(iOS 11, *)) {
+      if (context.biometryType == LABiometryTypeFaceID) {
+        return resolve(@"FaceID");
+      }
+    }
+    return resolve(@"TouchID");
+  }
+  return resolve([NSNull null]);
+}
+
 - (BOOL) canCheckAuthentication:(LAPolicy)policyToEvaluate error:(NSError **)err {
     return [[[ LAContext alloc] init ] canEvaluatePolicy:policyToEvaluate error:err ];
 }

index.js

@@ -1,6 +1,11 @@
 import { NativeModules, Platform } from 'react-native';
 const { RNKeychainManager } = NativeModules;
 
+export const BIOMETRY_TYPE = {
+  TOUCH_ID: 'TouchID',
+  FACE_ID: 'FaceID',
+};
+
 type SecAccessible =
   | 'AccessibleWhenUnlocked'
   | 'AccessibleAfterFirstUnlock'
@@ -49,6 +54,22 @@ export function canImplyAuthentication(options?: SecureOptions): Promise {
   return RNKeychainManager.canCheckAuthentication(options);
 }
 
+/**
+ * Get what type of local authentication policy (LAPolicy) is supported
+ * on this device with the device settings the user chose.
+ * @return {Promise} Resolves to a `BIOMETRY_TYPE` when supported, otherwise `null`
+ */
+export function getSupportedBiometryType(): Promise {
+  if (Platform.OS !== 'ios') {
+    return Promise.reject(
+      new Error(
+        `getSupportedBiometryType() is not supported on ${Platform.OS} yet`
+      )
+    );
+  }
+  return RNKeychainManager.getSupportedBiometryType();
+}
+
 /**
  * Saves the `username` and `password` combination for `service` securely - needs authentication to retrieve it.
  * @param {string} service Associated service.