fix: Stripe types and checks

[nicu-chiciuc]

Fixes #261

Adding types

I started by adding

// @deno-types="npm:stripe"

just above the Stripe import.
This is based on https://deno.com/manual@v1.34.0/advanced/typescript/types#providing-types-when-importing

This is not the best solution, but currently there's an issue with having types for Stripe in Deno:
stripe-samples/stripe-node-deno-samples#2

Covering all possibilities

After the initial error was fixed, I was receiving a different error, also caused by type assertions, so I had to change

pricePerInterval={toPricePerInterval(
                product.default_price as Stripe.Price,
              )}

and handle all cases

Testing

1. git clone ...
2. deno task start
3. access http://localhost:8000/pricing
4. you shouldn't see a 500 error

PS

defaultPrice.recurring?.interval already has a defined type, but I wasn't sure what's the correct way to import it in Deno. I left it as string since it's not a critical part of the app, it's used just for displaying text. So it's not a high-concern at the moment.

[nicu-chiciuc]

What should cd476cd accomplish?

[iuioiua]

My main thought is that the checks added in this PR aren't needed if the init:stripe task is run correctly. So having product.default_price as Stripe.Price is acceptable. If product.default_price is not of type Stripe.Price, we may have to investigate the init:stripe task, as it's not working correctly.

Either way, nice work fixing the Stripe types! I've added a suggestion to improve this situation for the whole codebase.

[iuioiua]

Can you move this to a stripe.ts file at the root of this codebase and point the stripe import in the import_map.json to that file? That way, all files that import stripe also get types.

Also, can you please add a version that ensures the types and runtime versions of stripe match?

[nicu-chiciuc]

I see, in that case a better solution would've been for me to not make these checks but throw a custom error/banner instead of relying on type assertions. That means I could remove most of the code checks.

[iuioiua]

Yes, I'd rather the code threw 👍🏾

[nicu-chiciuc]

I'm made the changes. Remove the type assertions and threw and error (had to create a type guard for this to work).

I still get an error on the pricing page, even after running deno task init:stripe since one of the elements in data doesn't have a default_price. But that's consistent with the previous implementation.

[nicu-chiciuc]

I've also moved the stripe definitions into stripe.ts. I had to change import in stripe-webhooks.ts so it uses a default export like all the other files.

[iuioiua]

I made a few fixes, and now LGTM! Thanks for this!

Note for future: please use deno task ok before git push-ing to ensure all checks pass.