diff --git a/examples/PasscodeAuthExample/Libraries/PasscodeAuth/PasscodeAuth.ios.js b/examples/PasscodeAuthExample/Libraries/PasscodeAuth/PasscodeAuth.ios.js
index 6ebc6d1..431ef24 100644
--- a/examples/PasscodeAuthExample/Libraries/PasscodeAuth/PasscodeAuth.ios.js
+++ b/examples/PasscodeAuthExample/Libraries/PasscodeAuth/PasscodeAuth.ios.js
@@ -28,7 +28,7 @@ var Passcode = {
     });
   },
 
-  authenticate(reason) {
+  authenticate(reason: string) {
     var authReason;
 
     // Set auth reason