Ng-storekit can't finish a purchasing transaction


#1

I'm using ionic framework to build an iOS application. Currently, I'm adding in app purchase for a subscription using ng-storekit. But, I'm getting this on console:

InAppPurchase[js]: exception in options.purchase: "TypeError: _onPurchase is not a function. (In '_onPurchase(transactionId, productId)', '_onPurchase' is undefined)"