# payment-customization

Shopify Function (`cart.payment-methods.transform.run`) that hides
cash-on-delivery / pay-in-store payment methods when the shopper's chosen
fulfillment method is `SHIPPING` (study §5.2 parity).

Pure decision logic lives in `src/evaluate.js` and is unit-tested at the
repo root (`tests/unit/payment-customization.test.ts`) with plain Vitest —
no WASM build needed for that.

## Before first build / deploy

`schema.graphql` and `generated/` are **not** committed (they're produced
by codegen and gitignored, same as the other Function extensions). Run:

```
npm --prefix extensions/payment-customization run typegen
```

to pull the API schema and regenerate `generated/api.ts`, then
`shopify app deploy` picks it up. The extension also needs the
`write_payment_customizations` scope, which `shopify.app.toml` already
requests, and the merchant must activate it under
**Settings → Payments → Payment method customizations** in the admin.