diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.h b/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.h
index 9f201735aaf2b06f00e7614cc897590b09152653..bf37c55c6b13f8ae4c3cd1df2cabc95bdd048408 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.h
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.h
@@ -12,6 +12,7 @@
 
 - (void)fitness_getStepCountOnDay:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
 - (void)fitness_getSamples:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
+- (void)fitness_setObserver:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
 - (void)fitness_getDailyStepSamples:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
 - (void)fitness_saveSteps:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
 - (void)fitness_initializeStepEventObserver:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.m b/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.m
index 08226a5a55e69e8644d0383dba1f5975e0f0cc29..5e6fc0d7c4ecff9784bcfe180a28921fffc7b543 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.m
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Methods_Fitness.m
@@ -91,6 +91,31 @@
                           }];
 }
 
+- (void)fitness_setObserver:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback
+{
+    HKUnit *unit = [RCTAppleHealthKit hkUnitFromOptions:input key:@"unit" withDefault:[HKUnit countUnit]];
+    NSString *type = [RCTAppleHealthKit stringFromOptions:input key:@"type" withDefault:@"Walking"];
+    
+    HKSampleType *samplesType = [HKObjectType quantityTypeForIdentifier:HKQuantityTypeIdentifierStepCount];
+    if ([type isEqual:@"Walking"]) {
+        samplesType = [HKObjectType quantityTypeForIdentifier:HKQuantityTypeIdentifierStepCount];
+    } else if ([type isEqual:@"StairClimbing"]) {
+        samplesType = [HKObjectType quantityTypeForIdentifier:HKQuantityTypeIdentifierFlightsClimbed];
+    } else if ([type isEqual:@"Running"]){
+        samplesType = [HKObjectType quantityTypeForIdentifier:HKQuantityTypeIdentifierDistanceWalkingRunning];
+        unit = [HKUnit mileUnit];
+    } else if ([type isEqual:@"Cycling"]){
+        samplesType = [HKObjectType quantityTypeForIdentifier:HKQuantityTypeIdentifierDistanceCycling];
+        unit = [HKUnit mileUnit];
+    } else if ([type isEqual:@"Workout"]){
+        samplesType = [HKObjectType workoutType];
+    }
+    
+    [self setObserverForType:samplesType unit:unit completion:^(NSArray *results, NSError * error) {
+        callback(@[[NSNull null], results]);
+    }];
+}
+
 
 - (void)fitness_getDailyStepSamples:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback
 {
diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.h b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.h
index 39dc12cbd56adccca00a8c43b98b9e4751690764..8eec34b4a6e4739025ea621ed1759ed554315f5a 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.h
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.h
@@ -18,12 +18,19 @@
                                      startDate:(NSDate *)startDate
                                        endDate:(NSDate *)endDate
                                     completion:(void (^)(NSArray *, NSError *))completionHandler;
+
+
 - (void)fetchSamplesOfType:(HKSampleType *)quantityType
                               unit:(HKUnit *)unit
                          predicate:(NSPredicate *)predicate
                          ascending:(BOOL)asc
                              limit:(NSUInteger)lim
                         completion:(void (^)(NSArray *, NSError *))completion;
+- (void)setObserverForType:(HKSampleType *)quantityType
+                      unit:(HKUnit *)unit
+                completion:(void (^)(NSArray *, NSError *))completion;
+
+
 - (void)fetchQuantitySamplesOfType:(HKQuantityType *)quantityType
                               unit:(HKUnit *)unit
                          predicate:(NSPredicate *)predicate
diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
index d28cb4beccf70bf79e53972757189d3f2de70d66..d84600ae890125f345b21d17dbff477e1e7d345b 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
@@ -9,6 +9,9 @@
 #import "RCTAppleHealthKit+Queries.h"
 #import "RCTAppleHealthKit+Utils.h"
 
+#import <React/RCTBridgeModule.h>
+#import <React/RCTEventDispatcher.h>
+
 @implementation RCTAppleHealthKit (Queries)
 
 
@@ -199,7 +202,65 @@
     [self.healthStore executeQuery:query];
 }
 
-
+- (void)setObserverForType:(HKSampleType *)type
+                      unit:(HKUnit *)unit
+                completion:(void (^)(NSArray *, NSError *))completion {
+    NSLog(@"set observer");
+    void(^handler)(HKObserverQuery *query, HKObserverQueryCompletionHandler completionHandler, NSError * _Nullable error);
+    handler = ^(HKObserverQuery *query, HKObserverQueryCompletionHandler completionHandler, NSError * _Nullable error) {
+        NSLog(@"enter to a handler %@", [error localizedDescription]);
+        UIApplication *app = [UIApplication sharedApplication];
+        UIApplicationState appState = [app applicationState];
+
+        if (!self.isSync){
+//            switch (appState) {
+//            case UIApplicationStateActive:
+//                NSLog(@"app Active try to make sync");
+//                break;
+//            case UIApplicationStateInactive:
+//                {
+//                    NSLog(@"enter to inactive case");
+//                break;
+//                }
+//            case UIApplicationStateBackground:
+//                {
+//                    NSLog(@"enter to background case");
+//                    self.isSync = true;
+//                    __block UIBackgroundTaskIdentifier backgroundTaskIdentifier = [app beginBackgroundTaskWithExpirationHandler:^{
+//
+//                        NSLog(@"call event background");
+////                        [self.bridge.eventDispatcher sendAppEventWithName:@"change:steps"
+////                                                                     body:@{@"name": @"change:steps"}];
+//                        [self fetchSamplesOfType:type unit:unit predicate:nil ascending:true limit:1 completion:completion];
+//                        [app endBackgroundTask:backgroundTaskIdentifier];
+//                        self.isSync = false;
+//                    }];
+//                }
+//
+//            };
+            
+            NSLog(@"enter to background case");
+            self.isSync = true;
+            __block UIBackgroundTaskIdentifier backgroundTaskIdentifier = [app beginBackgroundTaskWithExpirationHandler:^{
+                
+                NSLog(@"call event background");
+                                        [self.bridge.eventDispatcher sendAppEventWithName:@"change:steps"
+                                                                                     body:@{@"name": @"change:steps"}];
+                [self fetchSamplesOfType:type unit:unit predicate:nil ascending:true limit:1 completion:completion];
+                [app endBackgroundTask:backgroundTaskIdentifier];
+                completionHandler();
+                self.isSync = false;
+            }];
+        }
+        
+    };
+    HKObserverQuery *query = [[HKObserverQuery alloc] initWithSampleType:type predicate:nil updateHandler:handler];
+    
+    [self.healthStore executeQuery:query];
+    [self.healthStore enableBackgroundDeliveryForType:type frequency:HKUpdateFrequencyImmediate withCompletion:^(BOOL success, NSError * _Nullable error) {
+        NSLog(@"success %s print some error %@", success ? "true" : "false", [error localizedDescription]);
+    }];
+}
 
 
 
diff --git a/RCTAppleHealthKit/RCTAppleHealthKit.h b/RCTAppleHealthKit/RCTAppleHealthKit.h
index 39b603415c06570ff35b15f7a7c63b7e44b37606..900c6e39ccd9c0d1e04119cd4948d57d39c634c8 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit.h
+++ b/RCTAppleHealthKit/RCTAppleHealthKit.h
@@ -15,6 +15,7 @@
 @interface RCTAppleHealthKit : NSObject <RCTBridgeModule>
 
 @property (nonatomic) HKHealthStore *healthStore;
+@property BOOL isSync;
 
 - (void)isHealthKitAvailable:(RCTResponseSenderBlock)callback;
 - (void)initializeHealthKit:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
diff --git a/RCTAppleHealthKit/RCTAppleHealthKit.m b/RCTAppleHealthKit/RCTAppleHealthKit.m
index 04e3d575180d93a83a62a5fc11de34d00e8773d9..2d1fa49eb646e715a9a8053188273760da144c1e 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit.m
+++ b/RCTAppleHealthKit/RCTAppleHealthKit.m
@@ -111,6 +111,12 @@ RCT_EXPORT_METHOD(getSamples:(NSDictionary *)input callback:(RCTResponseSenderBl
     [self fitness_getSamples:input callback:callback];
 }
 
+RCT_EXPORT_METHOD(setObserver:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback)
+{
+    [self fitness_setObserver:input callback:callback];
+}
+
+
 RCT_EXPORT_METHOD(getDailyStepCountSamples:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback)
 {
     [self fitness_getDailyStepSamples:input callback:callback];