aretherecookies-mobile/js/apis/PositionApi.js

// @flow
import { emitter } from '../streams/LocationStream';
import { getCoordsFromZip } from './GoogleMapsApi';
import { AsyncStorage } from 'react-native';

export const getCurrentPosition = () => {
	return new Promise((resolve, reject) => {
		navigator.geolocation.getCurrentPosition(
			(pos: Position) => {
				emitter(pos), resolve(pos);
				return pos;
			},
			err => {
				reject(err);
			},
			{
				enableHighAccuracy: true,
				timeout: 2000,
				maximumAge: 1000,
			}
		);
	});
};

// TODO actually implement geolocation for zipcode into lat/lng
export const getPositionFromZip = async (zip: string) => {
	const { lat: latitude, lng: longitude } = await getCoordsFromZip(zip);

	const pos: any = {
		coords: {
			latitude,
			longitude,
		},
	};

	emitter(pos);

	return pos;
};

export const getLocation: () => Promise<Position> = async () => {
	const currentZip = await AsyncStorage.getItem('zipcode');

	if (currentZip && currentZip !== 'usegps') {
		return getPositionFromZip(currentZip);
	} else {
		AsyncStorage.setItem('zipcode', 'usegps');
		return getCurrentPosition().catch(error => {
			AsyncStorage.removeItem('zipcode');
			throw error;
		});
	}
};