MediaPlayerIOSPodcastTitles.m

@implementation MediaPlayerIOSPodcastTitles
@synthesize bridge = _bridge;

// Export a native module
// https://facebook.github.io/react-native/docs/native-modules-ios.html
RCT_EXPORT_MODULE();

// Export constants
// https://facebook.github.io/react-native/releases/next/docs/native-modules-ios.html#exporting-constants
- (NSDictionary *)constantsToExport
{
  return @{
           @"EXAMPLE": @"example"
         };
}

// Return the native view that represents your React component
- (UIView *)view
{
  return [[UIView alloc] init];
}

- (NSArray<NSString *> *)supportedEvents{
  return @[@"podcast-titles"];
}

// Export methods to a native module
// https://facebook.github.io/react-native/docs/native-modules-ios.html
RCT_REMAP_METHOD(getPodcastTitles, getPodcastTitlesWithResolver:(RCTPromiseResolveBlock)resolve
                  rejecter:(RCTPromiseRejectBlock)reject)
{
  [MPMediaLibrary requestAuthorization:^(MPMediaLibraryAuthorizationStatus status) {
    if (status == MPMediaLibraryAuthorizationStatusAuthorized) {
      MPMediaQuery *podcastsQuery = [MPMediaQuery podcastsQuery];
      NSMutableSet<NSString*> *podcastNameSet = [NSMutableSet set];
      for (MPMediaItem *podcast in podcastsQuery.items){
        NSString* unformattedPodcastTitle = podcast.podcastTitle;
        if (unformattedPodcastTitle){
          NSString *podcastTitle = [unformattedPodcastTitle plusSignEncoding];
          [podcastNameSet addObject:podcastTitle];
        }
      }
      NSArray *podcastTitlesArray = [podcastNameSet allObjects];
      resolve(podcastTitlesArray);
    }else{
      reject(@"300", @"Could not access your Podcast Library. Please adjust this in the Settings App", nil);
    }
  }];
}

MediaPlayerIOSPodcastTitlesNativeModule.js

//  Created by react-native-create-bridge

import { NativeModules } from 'react-native'

const { MediaPlayerIOSPodcastTitles } = NativeModules

export default {
  getPodcastTitles () {
    return MediaPlayerIOSPodcastTitles.getPodcastTitles()
  },

  EXAMPLE_CONSTANT: MediaPlayerIOSPodcastTitles.EXAMPLE_CONSTANT
}

StringUtils.m

#import "NSString+StringUtils.h"

@implementation NSString (StringUtils)

-(NSString*)plusSignEncoding{
  NSArray<NSString*>* words = [self componentsSeparatedByString:@" "];
  return [words componentsJoinedByString:@"+"];
}

@end