subscriptionIntroductoryOffer(applyOffer:compactJWS:)

Declaration

nonisolated func subscriptionIntroductoryOffer(applyOffer: @escaping (Product, Product.SubscriptionInfo) -> Bool, compactJWS: @escaping (Product, Product.SubscriptionInfo) async throws -> String) -> some View

Parameters

• applyOffer:

  The system calls this function before drawing the given subscription product on the subscription store view. Return if the introductory offer should be applied to a given product, if any, to have system-provided UI reflect the discounted terms under the selected offer.

• compactJWS:

  The system calls this function before processing a purchase, with the product to be purchased provided as a parameter. Return a compact JWS signature you generate on your server that validates the selected offer eligibility preference. Errors thrown from this closure will be surfaced via the Oninapppurchasecompletion(perform:) modifier. For information about generating the JWS signature, see Generating Jws To Sign App Store Requests.

Discussion

Subscription stores within this view uses the introductory subscription offers to configure the appearance of the subscription plans displayed, when you use a system-provided SubscriptionStoreControlStyle to style the in-app subscription store. Standard ProductViewStyle instances don’t show introductory or promotional offers in UI, instead use SubscriptionStoreView.

Determine if the introductory offer should be displayed in the view and applied to the purchase using the applyOffer. If the signature passes validation, the system applies or removes the offer to the purchases according to the offer eligibility preference. If the signature fails validation, the purchase will fail with Product.PurchaseError.invalidOfferSignature.