[Bluetooth] Added checking for null data

[Verification] BT auto 100%
Manual test BluetoothSocket - subtest BluetoothSocket_writeData_misarg fixed.

Change-Id: I44f27a5f5bee1dae73017ce736709b4c464471c2

diff --git a/src/bluetooth/bluetooth_api.js b/src/bluetooth/bluetooth_api.js
index d030dca..0564ba6 100755 (executable)
--- a/src/bluetooth/bluetooth_api.js
+++ b/src/bluetooth/bluetooth_api.js
@@ -3598,7 +3598,7 @@ var BluetoothManager_byteArrayToHexString = function(bytes) {
 }
 
 var BluetoothManager_toByteArray = function(data) {
-    if (String === data.constructor) {
+    if (data && String === data.constructor) {
         return numberArrayToByteArray(BluetoothManager_HexStringToUint8Array(data));
     } else {
         try {