Hide Cash on Delivery by country, province or ZIP code

api_version = "2026-10"

[[extensions]]
name = "Hide Cash on Delivery by region"
handle = "hide-cod-by-region"
type = "function"

  [[extensions.targeting]]
  target = "cart.payment-methods.transform.run"
  input_query = "src/cart_payment_methods_transform_run.graphql"
  export = "cart-payment-methods-transform-run"

  [extensions.build]
  command = ""
  path = "dist/function.wasm"

query CartPaymentMethodsTransformRunInput {
  cart {
    deliveryGroups {
      deliveryAddress {
        countryCode
        provinceCode
        zip
      }
    }
  }
  paymentMethods {
    id
    name
  }
  paymentCustomization {
    metafield(namespace: "$app", key: "function-configuration") {
      jsonValue
    }
  }
}

// @ts-check

/**
 * @typedef {import("../generated/api").CartPaymentMethodsTransformRunInput} CartPaymentMethodsTransformRunInput
 * @typedef {import("../generated/api").CartPaymentMethodsTransformRunResult} CartPaymentMethodsTransformRunResult
 */

/**
 * Settings stored as JSON in the customization's metafield. The region lists
 * are empty by default, so nothing is hidden until the merchant sets them.
 */
const DEFAULT_CONFIG = {
  // Matched case-insensitively against the start of the payment method name.
  methodNames: ["Cash on Delivery", "Kapıda Ödeme"],
  // ISO country codes, e.g. "US".
  countries: [],
  // Country and province code joined by a colon, e.g. "US:AK" or "CA:NU".
  provinces: [],
  // ZIP or postal code prefixes, e.g. "99" or "34450". Spaces are ignored.
  zipPrefixes: [],
};

/**
 * Lowercase for matching, with Turkish dotless/dotted i folded to "i", so
 * "KAPIDA ÖDEME" and "Kapıda Ödeme" match the same configured name.
 * @param {string} text
 */
const fold = (text) => text.toLowerCase().replace(/ı/g, "i").replace(/\u0307/g, "");

/** @type {CartPaymentMethodsTransformRunResult} */
const NO_CHANGES = { operations: [] };

/** @param {string | null | undefined} value */
const normalizeZip = (value) => (value ?? "").replace(/\s+/g, "").toUpperCase();

/**
 * @param {CartPaymentMethodsTransformRunInput} input
 * @returns {CartPaymentMethodsTransformRunResult}
 */
export function cartPaymentMethodsTransformRun(input) {
  const config = { ...DEFAULT_CONFIG, ...input.paymentCustomization?.metafield?.jsonValue };
  const countries = config.countries.map((code) => code.toUpperCase());
  const provinces = config.provinces.map((code) => code.toUpperCase());
  const zipPrefixes = config.zipPrefixes.map(normalizeZip).filter(Boolean);

  // A cart can ship to several addresses (split delivery); one excluded
  // address is enough, because COD applies to the whole order.
  const addresses = input.cart.deliveryGroups
    .map((group) => group.deliveryAddress)
    .filter((address) => address != null);
  const excluded = addresses.some((address) => {
    const country = (address.countryCode ?? "").toUpperCase();
    const province = `${country}:${(address.provinceCode ?? "").toUpperCase()}`;
    const zip = normalizeZip(address.zip);
    return (
      countries.includes(country) ||
      provinces.includes(province) ||
      (zip !== "" && zipPrefixes.some((prefix) => zip.startsWith(prefix)))
    );
  });
  if (!excluded) return NO_CHANGES;

  const names = config.methodNames.map(fold);
  const operations = input.paymentMethods
    .filter((method) => names.some((name) => fold(method.name).startsWith(name)))
    .map((method) => ({ paymentMethodHide: { paymentMethodId: method.id } }));

  return { operations };
}