Fix issue with promoted product event not firing on older devices

Author: neilco

README.md

@@ -367,6 +367,13 @@ We've like to update this solution as version changes in `react-native-iap`.
 #### How do I handle promoted products in ios?
 
 - Offical doc is [here](https://developer.apple.com/app-store/promoting-in-app-purchases/)
+- Start the IAPPromotionObserver in `-[application:didFinishLaunchingWithOptions:]` your AppDelegate:
+
+    ```objc
+    // Add '#import "IAPPromotionObserver.h"' to your imports
+    [IAPPromotionObserver startObserving]; 
+    ```
+
 - Add an event listener for the `iap-promoted-product` event somewhere early in your app's lifecycle:
 
   ```javascript

ios/IAPPromotionObserver.h

@@ -0,0 +1,21 @@
+#import <StoreKit/StoreKit.h>
+
+@protocol IAPPromotionObserverDelegate;
+
+@interface IAPPromotionObserver: NSObject <SKPaymentTransactionObserver>
+
+@property (strong, nonatomic, readonly) SKPayment *payment;
+@property (strong, nonatomic, readonly) SKProduct *product;
+@property (weak, nonatomic) id<IAPPromotionObserverDelegate> delegate;
+
++ (instancetype)sharedObserver;
++ (void)startObserving;
+
+@end
+
+@protocol IAPPromotionObserverDelegate <NSObject>
+
+@required
+- (BOOL)shouldAddStorePayment:(SKPayment *)payment forProduct:(SKProduct *)product;
+
+@end

ios/IAPPromotionObserver.m

@@ -0,0 +1,61 @@
+#import "IAPPromotionObserver.h"
+
+@interface IAPPromotionObserver () {
+  SKPayment *_promotedPayment;
+  SKProduct *_promotedProduct;
+}
+
+@end
+
+@implementation IAPPromotionObserver
+
++ (instancetype)sharedObserver {
+  static IAPPromotionObserver *sharedInstance = nil;
+  static dispatch_once_t onceToken;
+
+  dispatch_once(&onceToken, ^{
+    sharedInstance = [[IAPPromotionObserver alloc] init];
+  });
+
+  return sharedInstance;
+}
+
++ (void)startObserving {
+  [IAPPromotionObserver sharedObserver];
+}
+
+- (instancetype)init {
+  if ((self = [super init])) {
+    [SKPaymentQueue.defaultQueue addTransactionObserver:self];
+  }
+
+  return self;
+}
+
+-(void) dealloc {
+  [[SKPaymentQueue defaultQueue] removeTransactionObserver:self];
+}
+
+- (SKPayment *)payment {
+  return _promotedPayment;
+}
+
+- (SKProduct *)product {
+  return _promotedProduct;
+}
+
+- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray<SKPaymentTransaction *> *)transactions {
+}
+
+- (BOOL)paymentQueue:(SKPaymentQueue *)queue shouldAddStorePayment:(SKPayment *)payment forProduct:(SKProduct *)product {
+  _promotedProduct = product;
+  _promotedPayment = payment;
+
+  if (self.delegate != nil && [self.delegate respondsToSelector:@selector(shouldAddStorePayment:forProduct:)]) {
+    return [self.delegate shouldAddStorePayment:payment forProduct:product];
+  }
+
+  return NO;
+}
+
+@end

ios/RNIap.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		28CBF364220349F6005F51AC /* IAPPromotionObserver.m in Sources */ = {isa = PBXBuildFile; fileRef = 28CBF363220349F6005F51AC /* IAPPromotionObserver.m */; };
 		B3E7B58A1CC2AC0600A0062D /* RNIapIos.m in Sources */ = {isa = PBXBuildFile; fileRef = B3E7B5891CC2AC0600A0062D /* RNIapIos.m */; };
 /* End PBXBuildFile section */
 
@@ -24,6 +25,8 @@
 
 /* Begin PBXFileReference section */
 		134814201AA4EA6300B7C361 /* libRNIap.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = libRNIap.a; sourceTree = BUILT_PRODUCTS_DIR; };
+		28CBF362220349F6005F51AC /* IAPPromotionObserver.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = IAPPromotionObserver.h; sourceTree = "<group>"; };
+		28CBF363220349F6005F51AC /* IAPPromotionObserver.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = IAPPromotionObserver.m; sourceTree = "<group>"; };
 		B3E7B5881CC2AC0600A0062D /* RNIapIos.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RNIapIos.h; sourceTree = "<group>"; };
 		B3E7B5891CC2AC0600A0062D /* RNIapIos.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RNIapIos.m; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -52,6 +55,8 @@
 			children = (
 				B3E7B5881CC2AC0600A0062D /* RNIapIos.h */,
 				B3E7B5891CC2AC0600A0062D /* RNIapIos.m */,
+				28CBF362220349F6005F51AC /* IAPPromotionObserver.h */,
+				28CBF363220349F6005F51AC /* IAPPromotionObserver.m */,
 				134814211AA4EA7D00B7C361 /* Products */,
 			);
 			sourceTree = "<group>";
@@ -112,6 +117,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				28CBF364220349F6005F51AC /* IAPPromotionObserver.m in Sources */,
 				B3E7B58A1CC2AC0600A0062D /* RNIapIos.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

ios/RNIapIos.m

@@ -1,19 +1,18 @@
 #import "RNIapIos.h"
+#import "IAPPromotionObserver.h"
 
 #import <React/RCTLog.h>
 #import <React/RCTConvert.h>
 
 #import <StoreKit/StoreKit.h>
 
 ////////////////////////////////////////////////////     _//////////_  // Private Members
-@interface RNIapIos() {
+@interface RNIapIos() <IAPPromotionObserverDelegate> {
   NSMutableDictionary *promisesByKey;
   BOOL autoReceiptConform;
   SKPaymentTransaction *currentTransaction;
   dispatch_queue_t myQueue;
   BOOL hasListeners;
-  SKProduct *promotedProduct;
-  SKPayment *promotedPayment;
 }
 @end
 
@@ -24,6 +23,7 @@ -(instancetype)init {
   if ((self = [super init])) {
     promisesByKey = [NSMutableDictionary dictionary];
     [[SKPaymentQueue defaultQueue] addTransactionObserver:self];
+    [IAPPromotionObserver sharedObserver].delegate = self;
   }
   myQueue = dispatch_queue_create("reject", DISPATCH_QUEUE_SERIAL);
   validProducts = [NSMutableArray array];
@@ -49,6 +49,7 @@ - (void)stopObserving {
 - (void)addListener:(NSString *)eventName {
   [super addListener:eventName];
 
+  SKPayment *promotedPayment = [IAPPromotionObserver sharedObserver].payment;
   if ([eventName isEqualToString:@"iap-promoted-product"] && promotedPayment != nil) {
     [self sendEventWithName:@"iap-promoted-product" body:promotedPayment.productIdentifier];
   }
@@ -89,6 +90,14 @@ -(void)rejectPromisesForKey:(NSString*)key code:(NSString*)code message:(NSStrin
   }
 }
 
+////////////////////////////////////////////////////     _//////////_  // IAPPromotionObserverDelegate
+- (BOOL)shouldAddStorePayment:(SKPayment *)payment forProduct:(SKProduct *)product {
+  if (hasListeners) {
+    [self sendEventWithName:@"iap-promoted-product" body:product.productIdentifier];
+  }
+  return NO;
+}
+
 ////////////////////////////////////////////////////     _//////////_//      EXPORT_MODULE
 RCT_EXPORT_MODULE();
 
@@ -209,11 +218,13 @@ -(void)rejectPromisesForKey:(NSString*)key code:(NSString*)code message:(NSStrin
 RCT_EXPORT_METHOD(promotedProduct:(RCTPromiseResolveBlock)resolve
                   reject:(RCTPromiseRejectBlock)reject) {
   NSLog(@"\n\n\n  ***  get promoted product. \n\n.");
+  SKProduct *promotedProduct = [IAPPromotionObserver sharedObserver].product;
   resolve(promotedProduct ? promotedProduct.productIdentifier : [NSNull null]);
 }
 
 RCT_EXPORT_METHOD(buyPromotedProduct:(RCTPromiseResolveBlock)resolve
                   reject:(RCTPromiseRejectBlock)reject) {
+  SKPayment *promotedPayment = [IAPPromotionObserver sharedObserver].payment;
   if (promotedPayment) {
     NSLog(@"\n\n\n  ***  buy promoted product. \n\n.");
     [[SKPaymentQueue defaultQueue] addPayment:promotedPayment];
@@ -318,18 +329,6 @@ -(void)paymentQueue:(SKPaymentQueue *)queue restoreCompletedTransactionsFailedWi
   NSLog(@"\n\n\n restoreCompletedTransactionsFailedWithError \n\n.");
 }
 
-- (BOOL)paymentQueue:(SKPaymentQueue *)queue shouldAddStorePayment:(SKPayment *)payment forProduct:(SKProduct *)product {
-  NSLog(@"\n\n\n  ***  should add store payment. \n\n.");
-  promotedProduct = product;
-  promotedPayment = payment;
-
-  if (hasListeners) {
-    [self sendEventWithName:@"iap-promoted-product" body:payment.productIdentifier];
-  }
-
-  return NO;
-}
-
 -(void)purchaseProcess:(SKPaymentTransaction *)transaction {
   if (autoReceiptConform) {
     [[SKPaymentQueue defaultQueue] finishTransaction:transaction];