Author here. I've been working on this post for more than a month, and it represents more than 30 hours of writing / code samples on top of another two months of learning and building subscription products. Hope you find it helpful, and happy to answer any questions you have here!
Great article. It will be great for the Angular community if it is Angular + Stripe.
It is so hard to find one for Angular + Stripe. A good one like how you wrote it.