Added OnSubscriptionChange view modifier

README.md

@@ -27,6 +27,8 @@ Check out the [Quick Start Tutorial](https://russell-archer.github.io/SKHelper/t
 ---
 
 # Recent Major Changes
+- 6 Oct, 2024
+    - Fixed logging bug with release build; added `onSubscriptionChange(onChange:)` View modifier
 - 27 Sep, 2024
     - Improved support for consumables 
 - 23 Sep, 2024

Sources/SKHelper/Core/SKHelper+Extensions.swift

@@ -5,6 +5,7 @@
 //  Created by Russell Archer on 04/08/2024.
 //
 
+public import SwiftUI
 public import StoreKit
 
 public typealias ProductId = String
@@ -233,7 +234,7 @@ public extension SKHelper {
     /// - Parameter transactionId: The transaction's unique id.
     /// - Returns: Returns the `Transaction` associated with the unique id, or nil if the transaction cannot be found or can't be verified.
     ///
-    func transaction(for transactionId: UInt64) async -> Transaction? {
+    func transaction(for transactionId: UInt64) async -> StoreKit.Transaction? {
         for await transactionResult in Transaction.all {
             if transactionResult.unsafePayloadValue.id != transactionId { continue }
 
@@ -364,3 +365,51 @@ public enum SKHelperEntitlementState {
     /// Access to the purchase has been revoked by the App Store.
     case revoked
 }
+
+// MARK: - OnSubscriptionChange
+
+/// The `OnSubscriptionChange` ViewModifier allows you to be notified of changes to the status of all subscriptions.
+/// See also the `onSubscriptionChange(onChange:)` View extension.
+public struct OnSubscriptionChange: ViewModifier {
+    /// The `SKHelper` object.
+    @Environment(SKHelper.self) private var store
+
+    /// Optional handler allows you to be notified of changes to the status of all subscriptions.
+    private var onChange: SubscriptionStatusChangeClosure?
+
+    /// Creates an `OnSubscriptionChange` ViewModifier.
+    /// - Parameter onChange: Optional handler allows you to be notified of changes to the status of all subscriptions.
+    public init(onChange: SubscriptionStatusChangeClosure? = nil) { self.onChange = onChange }
+
+    /// Builds the body of the `OnSubscriptionChange` view modifier.
+    /// - Parameter content: The View's content.
+    /// - Returns: Returns the body of the `OnSubscriptionChange` view modifier.
+    public func body(content: Content) -> some View {
+        content
+            .onAppear {
+                store.subscriptionStatusChange = { productId, transactionId, renewalState, hasExpired in
+                    let newState = renewalState.localizedDescription.lowercased(with: Locale.current)
+                    print("Subscription \(productId) now \"\(newState)\" with transaction id \(transactionId). The subscription has \(hasExpired ? "expired" : "not expired").")
+
+                    onChange?(productId, transactionId, renewalState, hasExpired)
+                }
+            }
+    }
+}
+
+// MARK: - onSubscriptionChange(onChange:) View extension
+
+public extension View {
+
+    /// View extension to provide a `onSubscriptionChange(onChange:)` modifier.
+    /// ```
+    /// // Example usage:
+    /// SKHelperSubscriptionStoreView()
+    ///     .onSubscriptionChange() { productId, transactionId, renewalState, hasExpired  in
+    ///         print("The status of subscription \(productId) changed to \(renewalState.localizedDescription)")
+    ///     }
+    /// ```
+    public func onSubscriptionChange(onChange: SubscriptionStatusChangeClosure? = nil) -> some View {
+        modifier(OnSubscriptionChange(onChange: onChange))
+    }
+}