react-native-permissions/permissions/RNPLocation.m

//
//  RNPLocation.m
//  ReactNativePermissions
//
//  Created by Yonah Forst on 11/07/16.
//  Copyright © 2016 Yonah Forst. All rights reserved.
//

#import "RNPLocation.h"
#import <CoreLocation/CoreLocation.h>


@interface RNPLocation() <CLLocationManagerDelegate>
@property (strong, nonatomic) CLLocationManager* locationManager;
@property (copy) void (^completionHandler)(NSString *);
@end

@implementation RNPLocation

+ (NSString *)getStatus
{
    int status = [CLLocationManager authorizationStatus];
    switch (status) {
        case kCLAuthorizationStatusAuthorizedAlways:
        case kCLAuthorizationStatusAuthorizedWhenInUse:
            return RNPStatusAuthorized;
        case kCLAuthorizationStatusDenied:
            return RNPStatusDenied;
        case kCLAuthorizationStatusRestricted:
            return RNPStatusRestricted;
        default:
            return RNPStatusUndetermined;
    }
}

- (void)request:(NSString*)type completionHandler:(void (^)(NSString *))completionHandler
{
    NSString *status = [RNPLocation getStatus];
    if (status == RNPStatusUndetermined) {
        dispatch_async(dispatch_get_main_queue(), ^(){
            self.completionHandler = completionHandler;
            
            self.locationManager = [[CLLocationManager alloc] init];
            self.locationManager.delegate = self;
                
            if ([type isEqualToString:@"always"]) {
                [self.locationManager requestAlwaysAuthorization];
            } else {
                [self.locationManager requestWhenInUseAuthorization];
            }
        });
    } else {
        completionHandler(status);
    }
}

-(void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    if (status != kCLAuthorizationStatusNotDetermined) {
        if (self.locationManager) {
            self.locationManager.delegate = nil;
            self.locationManager = nil;
        }

        if (self.completionHandler) {
            //for some reason, checking permission right away returns denied. need to wait a tiny bit
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0.1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
                self.completionHandler([RNPLocation getStatus]);
                self.completionHandler = nil;
            });
        }
    }
}

@end