TypeError: Null is not an object

[Chiinyee]

Hi, I read that this library supports iOS. I am trying this on iOS simulator but when I call this method:
BLEPeripheral.addCharacteristicToService('XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX', 'XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX', 16 | 1, 8)

it returns TypeError: Null is not an object. So i console.log(BLEPeripheral), it prints out null as well. I have followed the instructions and link the library through react-native link but still have the problem. I am running on rn 0.6 and ios13. Below is a screenshot of the error:

May I know if I am doing anything wrong or will there be a fix soon for this problem?