How to use the react-native-code-push.getCurrentPackage function in react-native-code-push

componentDidMount() {
    DeviceInfo.gatherDeviceInfo().then((result) => {
      const deviceInfo = stringify(result);
      this.setState({ deviceInfo });
    });
    codePush.getCurrentPackage().then((result) => {
      const packageInfo = result ? stringify(result) : 'no package';
      this.setState({ packageInfo });
    });
  }

export const getCodePushHash = () => codePush.getCurrentPackage().then(result => (
  result ? result.packageHash.slice(0, 7) : '00000000'
));