access asyncLocalStorage in objective-c

0.m

  // add libReact.a
  
  // import
  #import "RCTAsyncLocalStorage.h"

  // code
  RCTAsyncLocalStorage *asyncLocalStorage = [[RCTAsyncLocalStorage alloc] init];
  
  dispatch_async([asyncLocalStorage methodQueue], ^{
    [asyncLocalStorage multiGetKeys:@[@"widget_city"] callback:^(NSArray *response){
      NSLog(@"%@", response);
      
      dispatch_async(dispatch_get_main_queue(), ^{
        [self populateViewForCity];
      });

    }];
  });

1.RCTAsyncLocalStorage.h

- (void)multiGetKeys:(NSArray<NSString *> *)keys callback:(RCTResponseSenderBlock)callback;

2.RCTAsyncLocalStorage.m

- (void)multiGetKeys:(NSArray<NSString *> *)keys
                 callback:(RCTResponseSenderBlock)callback
{
  NSDictionary *errorOut = [self _ensureSetup];
  if (errorOut) {
    callback(@[@[errorOut], (id)kCFNull]);
    return;
  }
  NSMutableArray<NSDictionary *> *errors;
  NSMutableArray<NSArray<NSString *> *> *result = [[NSMutableArray alloc] initWithCapacity:keys.count];
  for (NSString *key in keys) {
    id keyError;
    id value = [self _getValueForKey:key errorOut:&keyError];
    [result addObject:@[key, RCTNullIfNil(value)]];
    RCTAppendError(keyError, &errors);
  }
  callback(@[RCTNullIfNil(errors), result]);
}


#pragma mark - Exported JS Functions

RCT_EXPORT_METHOD(multiGet:(NSArray<NSString *> *)keys
                  callback:(RCTResponseSenderBlock)callback)
{
  [self multiGetKeys:keys callback:callback];
}