feat: Added missing info to IAP transaction and product structures

[kevinlinv]

Description of Change

The In-app purchase is a module that allows us to communicate with Apple's Mac App Store by using Store Kit. It allows us to get product information to be displayed to users and make purchases if users choose to do so.

There are a few missing fields in the data structures used for in-app purchase, specifically subscription information on Product and payment discount information on Transaction. Referencable from:

• Product: https://developer.apple.com/documentation/storekit/skproduct
• Transaction: https://developer.apple.com/documentation/storekit/skpaymenttransaction
  • payment: https://developer.apple.com/documentation/storekit/skpayment

This PR register those missing fields to the structure definition, get and convert the data to be returned.

Resolves #31738.

⚠️ Disclaimer ⚠️

This is the first time I've ever coded in C++ or Objective-C I mostly followed prior PR: #25058. I would be happy for maintainers to take it over if it would get the PR move along faster.

Also, I wasn't able to get electron build locally (running to errors when using build-tools), is there any way for me to get a build of electron for mac from CI so that I could test the in-app purchase? The artifacts seem to be uploaded in CI, given that I can pass the build that is.

Checklist

• PR description included and stakeholders cc'd
• relevant documentation is changed or added
• PR release notes describe the change in a way relevant to app developers and are capitalized, punctuated, and past tense.

Release Notes

Notes: feat: Added missing info to in-app purchase's transaction and product structures

[welcome]

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[kevinlinv]

Would love to get this backported to v15 v16 if possible.

[codebytere]

hey @kevinlinv! thanks for this - we'll start the review process as soon as we can!

[jkleinsc]

API LGTM

[kevinlinv]

@nornagon thank you for the review! 🙌

Quick summary of changes applied after your feedback:

1. On exposing empty value to JS when there one from Objective C is unset — I've changed all to do as you suggested, it also follows the existing pattern of the module 👍
2. On why nonce is commented out — I've left a comment, need some help to read UUID in Objective C.
3. On removing nil check — I tried and found out that removing those checks actually causes the app to crash when the value is unset.

PTAL again 🙂

[kevinlinv]

@nornagon thank you for the quick feedback loop.

Apologies for the slowness, I am do not have the setup locally and not well versed with the syntax 😅
I've addressed your feedback, PTAL again 👍

[nornagon]

Changing backport labels because we don't backport new features to stable branches without @electron/wg-releases approval.

[welcome]

Congrats on merging your first pull request! 🎉🎉🎉

[release-clerk]

Release Notes Persisted

Added missing info to in-app purchase's transaction and product structures.

[trop]

I have automatically backported this PR to "17-x-y", please check out #32602