Getting location from another file using Promise in react native with react-native-geolocation-service

I’m trying to make a helper function to get the current location of the user, but the result of my promise is undefined.

This function is working and I can retrieve my coordinates :

//position.js

async function getCurrentPosition() {
  return new Promise((resolve, reject) => {
    Geolocation.getCurrentPosition(resolve, reject, {
      enableHighAccuracy: true,
      timeout: 15000,
      maximumAge: 10000,
    });
  });
}

export async function getUserLocation() {
  await request(
    // Check for permissions
    Platform.select({
      android: PERMISSIONS.ANDROID.ACCESS_COARSE_LOCATION,
      ios: PERMISSIONS.IOS.LOCATION_WHEN_IN_USE,
    }),
  ).then((res) => {
    console.log('then');
    // Permission OK
    if (res === 'granted') {
      console.log('granted');
      return getCurrentPosition();
      // Permission denied
    } else {
      console.log('Location is not enabled');
    }
  });
}

But when I call my function here, I get undefined :

import {getUserLocation} from '../../utils/position';

useEffect(() => {
    getUserLocation()
      .then((res) => console.log(res)) // { undefined }
      .catch((err) => {
        console.error(err.message);
      });
  }, []);

What am I doing wrong?

Answer

As written, getUserLocation() does not return its request(…).then() promise. Change await to return.

Also, you should really change console.log('Location is not enabled') to throw new Error('Location is not enabled'), thus allowing getUserLocation’s caller to see the error (should it arise).

export async function getUserLocation() {
    return request(Platform.select({ // Check for permissions
 // ^^^^^^
        'android': PERMISSIONS.ANDROID.ACCESS_COARSE_LOCATION,
        'ios': PERMISSIONS.IOS.LOCATION_WHEN_IN_USE
    }))
    .then((res) => {
        if (res === 'granted') { // Permission OK
            return getCurrentPosition();
        } else { // Permission denied
            throw new Error('Location is not enabled'); // Throwing an Error here
                                                        // makes it available to the caller
                                                        // in its catch clause.
        }
    });
}