React native get local timezone from iOS system

getTimezone.js

import {NativeModules} from 'react-native'
const {HBTimezone} = NativeModules;
const getTimezone = () => new Promise((resolve, reject) =>
  HBTimezone.getTimezone((err, res) => {
    if (err) return reject(new Error(err));
    return resolve(res);
  })
);

export default getTimezone;

HBTimezone.h

#import <Foundation/Foundation.h>
#import "RCTBridgeModule.h"


@interface HBTimezone : NSObject <RCTBridgeModule>

@end

HBTimezone.m

#import "HBTimezone.h"

@implementation HBTimezone

RCT_EXPORT_METHOD(getTimezone:(RCTResponseSenderBlock)callback) {
  NSTimeZone *currentTimeZone = [NSTimeZone localTimeZone];
  callback(@[[NSNull null], currentTimeZone.name]);
};

RCT_EXPORT_MODULE();
@end

I couldn't find an easy way to just get the local timezone from the system on iOS, so I created this small bridge module.