How do I disable the device back button on Android (react-native)?

How can I disable the physical device back button on Android with React-Native? I don't want to enable it for the user.

Current open screen is tracked with a listener created when the application is launched, in app.js. Main component of the app creates a BackHandler listener, which responds to the device back button according to the currently open screen.

Main component:

componentDidMount() {
  BackHandler.addEventListener('hardwareBackPress', this.onBackPress);
}

componentWillUnmount() {
  BackHandler.removeEventListener('hardwareBackPress', this.onBackPress);
}

onBackPress = () => {
  if (this.props.currentScreen.name === 'app.main') {
     Alert.alert(
       'Confirm exit',
       'Do you want to exit App?',
       [
         {text: 'CANCEL', style: 'cancel'},
         {text: 'OK', onPress: () => {
           BackHandler.exitApp()
          }
        }
       ]
    );
  } else {
    Navigation.pop(this.props.currentScreen.id);
  }

  return true;
}

App.js

//register to compomentDidApperaListener to keep track on which screen is currently open. The componentName and Id are stored in my redux store
Navigation.events().registerComponentDidAppearListener(({ componentId, componentName }) => {
  store.dispatch(updateCurrentScreen({'name': componentName, 'id': componentId}))
})