From bafb8a4479ee65b8cd5cb9c40b1ebc5caed98aae Mon Sep 17 00:00:00 2001
From: Luis Alvarez <luis@vercel.com>
Date: Thu, 21 Jan 2021 21:19:53 -0500
Subject: [PATCH] Added useResponse hook

---
 framework/bigcommerce/cart/use-cart.tsx      | 33 +++++++---------
 framework/commerce/cart/use-cart.tsx         |  3 --
 framework/commerce/utils/types.ts            |  2 +
 framework/commerce/utils/use-data.tsx        |  2 +-
 framework/commerce/utils/use-response.tsx    | 40 ++++++++++++++++++++
 framework/commerce/wishlist/use-wishlist.tsx |  1 -
 6 files changed, 57 insertions(+), 24 deletions(-)
 create mode 100644 framework/commerce/utils/use-response.tsx

diff --git a/framework/bigcommerce/cart/use-cart.tsx b/framework/bigcommerce/cart/use-cart.tsx
index 708db68c5..c1a9bed7a 100644
--- a/framework/bigcommerce/cart/use-cart.tsx
+++ b/framework/bigcommerce/cart/use-cart.tsx
@@ -1,10 +1,9 @@
 import { normalizeCart } from '../lib/normalize'
 import type { HookFetcher } from '@commerce/utils/types'
 import type { SwrOptions } from '@commerce/utils/use-data'
-import defineProperty from '@commerce/utils/define-property'
+import useResponse from '@commerce/utils/use-response'
 import useCommerceCart, { CartInput } from '@commerce/cart/use-cart'
 import type { Cart as BigCommerceCart } from '../api/cart'
-import update from '@framework/lib/immutability'
 
 const defaultOpts = {
   url: '/api/bigcommerce/cart',
@@ -30,25 +29,21 @@ export function extendHook(
       revalidateOnFocus: false,
       ...swrOptions,
     })
-
-    // Uses a getter to only calculate the prop when required
-    // response.data is also a getter and it's better to not trigger it early
-    if (!('isEmpty' in response)) {
-      defineProperty(response, 'isEmpty', {
-        get() {
-          return Object.values(response.data?.line_items ?? {}).every(
-            (items) => !items.length
-          )
+    const res = useResponse(response, {
+      normalizer: normalizeCart,
+      descriptors: {
+        isEmpty: {
+          get() {
+            return Object.values(response.data?.line_items ?? {}).every(
+              (items) => !items.length
+            )
+          },
+          enumerable: true,
         },
-        set: (x) => x,
-      })
-    }
+      },
+    })
 
-    return response.data
-      ? update(response, {
-          data: { $set: normalizeCart(response.data) },
-        })
-      : response
+    return res
   }
 
   useCart.extend = extendHook
diff --git a/framework/commerce/cart/use-cart.tsx b/framework/commerce/cart/use-cart.tsx
index 513c041ea..c0fd10a5e 100644
--- a/framework/commerce/cart/use-cart.tsx
+++ b/framework/commerce/cart/use-cart.tsx
@@ -1,4 +1,3 @@
-import type { responseInterface } from 'swr'
 import Cookies from 'js-cookie'
 import type { HookInput, HookFetcher, HookFetcherOptions } from '../utils/types'
 import useData, { ResponseState, SwrOptions } from '../utils/use-data'
@@ -17,12 +16,10 @@ export default function useCart<Result>(
   swrOptions?: SwrOptions<Result, CartInput>
 ): CartResponse<Result> {
   const { cartCookie } = useCommerce()
-
   const fetcher: typeof fetcherFn = (options, input, fetch) => {
     input.cartId = Cookies.get(cartCookie)
     return fetcherFn(options, input, fetch)
   }
-
   const response = useData(options, input, fetcher, swrOptions)
 
   return response
diff --git a/framework/commerce/utils/types.ts b/framework/commerce/utils/types.ts
index b983d3391..2cd838964 100644
--- a/framework/commerce/utils/types.ts
+++ b/framework/commerce/utils/types.ts
@@ -22,3 +22,5 @@ export type HookFetcherOptions = {
 }
 
 export type HookInput = [string, string | number | boolean | undefined][]
+
+export type Override<T, K> = Omit<T, keyof K> & K
diff --git a/framework/commerce/utils/use-data.tsx b/framework/commerce/utils/use-data.tsx
index 00d7c8c31..a921eb529 100644
--- a/framework/commerce/utils/use-data.tsx
+++ b/framework/commerce/utils/use-data.tsx
@@ -64,7 +64,7 @@ const useData: UseData = (options, input, fetcherFn, swrOptions) => {
       get() {
         return response.data === undefined
       },
-      set: (x) => x,
+      enumerable: true,
     })
   }
 
diff --git a/framework/commerce/utils/use-response.tsx b/framework/commerce/utils/use-response.tsx
new file mode 100644
index 000000000..f3a1ed071
--- /dev/null
+++ b/framework/commerce/utils/use-response.tsx
@@ -0,0 +1,40 @@
+import { useMemo } from 'react'
+import { responseInterface } from 'swr'
+import { CommerceError } from './errors'
+import { Override } from './types'
+
+export type UseResponseOptions<
+  D,
+  R extends responseInterface<any, CommerceError>
+> = {
+  descriptors?: PropertyDescriptorMap
+  normalizer?: (data: R['data']) => D
+}
+
+export type UseResponse = <D, R extends responseInterface<any, CommerceError>>(
+  response: R,
+  options: UseResponseOptions<D, R>
+) => D extends object ? Override<R, { data?: D }> : R
+
+const useResponse: UseResponse = (response, { descriptors, normalizer }) => {
+  const memoizedResponse = useMemo(
+    () =>
+      Object.create(response, {
+        ...descriptors,
+        ...(normalizer
+          ? {
+              data: {
+                get() {
+                  return normalizer(response.data)
+                },
+                enumerable: true,
+              },
+            }
+          : {}),
+      }),
+    [response]
+  )
+  return memoizedResponse
+}
+
+export default useResponse
diff --git a/framework/commerce/wishlist/use-wishlist.tsx b/framework/commerce/wishlist/use-wishlist.tsx
index 62b1c8702..df8bebe5c 100644
--- a/framework/commerce/wishlist/use-wishlist.tsx
+++ b/framework/commerce/wishlist/use-wishlist.tsx
@@ -1,4 +1,3 @@
-import type { responseInterface } from 'swr'
 import type { HookInput, HookFetcher, HookFetcherOptions } from '../utils/types'
 import useData, { ResponseState, SwrOptions } from '../utils/use-data'