Typeerror: Undefined Is Not an Object( Evaluating 'Navigator. Geolocation. getCurrentPosition') in React-Native-Google-Places-Autocomplete

I am trying to use react-native-google-places-autocomplete for google places and at the sametime I want user current position also.

But im getting an error called as

TypeError: undefined is not an object( evaluating 'navigator.geolocation.getCurrentPosition')

i have gone through net searching for solutions everyone saying navigator.geolocation.getCurrentPosition works fine.

but dont know why it is not working for me..

Here is my code

componentDidMount() {
navigator.geolocation.getCurrentPosition(
  position => {
    const initialPosition = JSON.stringify(position);
    let region = {
        latitude: position.coords.latitude,
        longitude: position.coords.longitude,
        latitudeDelta: 0.0922,
        longitudeDelta: 0.0421,
        }
    this.setState({initialPosition:region});
    console.log("lat "+position.coords.latitude+" longi "+position.coords.longitude)
    console.log("initialPosition")
    console.log(this.state.initialPosition)
  },
   error => console.log("Error "+ JSON.stringify(error)),
  {enableHighAccuracy: true, timeout: 20000, maximumAge: 1000},
);
this.watchID = Geolocation.watchPosition(position => {
  const lastPosition = JSON.stringify(position);
  this.setState({lastPosition});
});

}