aretherecookies-mobile/js/apis/PositionApi.js

// @flow
import { emitter } from "../streams/LocationStream";
import { getCoordsFromZip } from "./GoogleMapsApi";
import { AsyncStorage, PermissionsAndroid, Platform } from "react-native";
import Geolocation from "react-native-geolocation-service";

const {
	PERMISSIONS: { ACCESS_FINE_LOCATION },
	RESULTS,
	request: requestPermission
} = PermissionsAndroid;

let locationPermissionResponse = false;

const askLocationPermission = async () => {
	if (Platform.OS === "ios") {
		locationPermissionResponse = RESULTS.GRANTED;
	} else if (locationPermissionResponse !== RESULTS.GRANTED) {
		locationPermissionResponse = await requestPermission(ACCESS_FINE_LOCATION, {
			title: "Aretherecookies? Location Permission",
			message: "Aretherecookies? would like to use your location to find some cookies. Is that OK?"
		});
	}
	return locationPermissionResponse === RESULTS.GRANTED;
};

export const getCurrentPosition = () => {
	return new Promise((resolve, reject) => {
		askLocationPermission().then(granted => {
			if (!granted) {
				return reject("Permission was not given for location");
			}
			Geolocation.getCurrentPosition(
				(pos: Position) => {
					emitter(pos), resolve(pos);
					return pos;
				},
				err => {
					reject(err);
				},
				{
					enableHighAccuracy: true,
					timeout: 5000
				}
			);
		});
	});
};

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;
		});
	}
};