Add sandbox agnostic receipt verification

Author: ninjaboy

index.ts

@@ -420,7 +420,7 @@ export const getSubscriptions = (skus: string[]): Promise<Subscription[]> =>
  * @returns {Promise<(InAppPurchase | SubscriptionPurchase)[]>}
  */
 export const getPurchaseHistory = (): Promise<(
-InAppPurchase | SubscriptionPurchase
+  InAppPurchase | SubscriptionPurchase
 )[]> =>
   Platform.select({
     ios: async () => {
@@ -450,7 +450,7 @@ InAppPurchase | SubscriptionPurchase
  * @returns {Promise<(InAppPurchase | SubscriptionPurchase)[]>}
  */
 export const getAvailablePurchases = (): Promise<(
-InAppPurchase | SubscriptionPurchase
+  InAppPurchase | SubscriptionPurchase
 )[]> =>
   Platform.select({
     ios: async () => {
@@ -649,7 +649,7 @@ export const finishTransaction = (
         } else if (
           purchase.userIdAmazon ||
           (!purchase.isAcknowledgedAndroid &&
-          purchase.purchaseStateAndroid === PurchaseStateAndroid.PURCHASED)
+            purchase.purchaseStateAndroid === PurchaseStateAndroid.PURCHASED)
         ) {
           return myRNIapModule.acknowledgePurchase(
             purchase.purchaseToken,
@@ -807,10 +807,46 @@ export const validateReceiptIos = async (
   receiptBody: Record<string, unknown>,
   isTest?: boolean,
 ): Promise<Apple.ReceiptValidationResponse | false> => {
+  if (isTest == null) {
+    return await requestAgnosticReceiptValidationIos(receiptBody);
+  }
+
   const url = isTest
     ? 'https://sandbox.itunes.apple.com/verifyReceipt'
     : 'https://buy.itunes.apple.com/verifyReceipt';
 
+  const response = await fetchJsonOrThrow(
+    url,
+    receiptBody,
+  );
+  return response;
+};
+
+const requestAgnosticReceiptValidationIos = async (
+  receiptBody: Record<string, unknown>,
+): Promise<Apple.ReceiptValidationResponse | false> => {
+  const response = await fetchJsonOrThrow(
+    'https://buy.itunes.apple.com/verifyReceipt',
+    receiptBody,
+  );
+
+  // Best practice is to check for test receipt and check sandbox instead 
+  // https://developer.apple.com/documentation/appstorereceipts/verifyreceipt
+  if (response && response.status === Apple.ReceiptValidationStatus.TEST_RECEIPT) {
+    const response = await fetchJsonOrThrow(
+      'https://sandbox.itunes.apple.com/verifyReceipt',
+      receiptBody,
+    );
+    return response;
+  }
+
+  return response;
+};
+
+const fetchJsonOrThrow = async (
+  url: string,
+  receiptBody: Record<string, unknown>,
+): Promise<Apple.ReceiptValidationResponse | false> => {
   const response = await fetch(url, {
     method: 'POST',
     headers: new Headers({