How to convert js to typescript in reactnative

I am new to react-native. I have a code with js and would like to convert this to typescript. This has 2 error

erorr1:Cannot find name 'componentDidMount'.ts(2304)erorr2:Object is possibly 'undefined'.ts(2532)

my js code is:

componentDidMount(){  this.state.deviceEmitterSubscription = DeviceEventEmitter.addListener('anything',    (intent) => {      this.broadcastReceiver(intent);    }  );  this.registerBroadcastReceiver();  this.determineVersion();}