initial provider (#2)

framework/medusa/cart/use-cart.tsx

@@ -0,0 +1,76 @@
+import { useMemo } from 'react'
+import { SWRHook } from '@commerce/utils/types'
+import useCart, { UseCart } from '@commerce/cart/use-cart'
+import { normalizeCart } from '@framework/utils/normalizers/normalize-cart'
+import { CommerceError } from '@commerce/utils/errors'
+
+import Cookies from 'js-cookie'
+import { MEDUSA_CART_ID_COOKIE } from '@framework/const'
+
+export default useCart as UseCart<typeof handler>
+
+export const handler: SWRHook<any> = {
+  fetchOptions: {
+    query: '',
+  },
+  async fetcher({ fetch }) {
+    const cart_id = Cookies.get(MEDUSA_CART_ID_COOKIE)
+
+    /**
+     * If cart already exits, then try to fetch it
+     */
+    if (cart_id) {
+      try {
+        const existingCartResponse = await fetch({
+          query: 'carts',
+          method: 'retrieve',
+          variables: { cart_id: cart_id },
+        })
+
+        if (existingCartResponse?.cart) {
+          return normalizeCart(existingCartResponse.cart)
+        }
+      } catch (e) {
+        /**
+         * noop: If the cart_id does not exits, then we
+         * continue and create a new cart and set a new
+         * CART_COOKIE
+         */
+      }
+    }
+
+    const newCartResponse = await fetch({
+      query: 'carts',
+      method: 'create',
+      variables: {},
+    })
+
+    if (newCartResponse?.cart) {
+      Cookies.set(MEDUSA_CART_ID_COOKIE, newCartResponse.cart.id, {
+        expires: 30,
+      })
+      return normalizeCart(newCartResponse.cart)
+    }
+    throw new CommerceError({ message: 'Medusa cart error' })
+  },
+  useHook:
+    ({ useData }) =>
+    (input) => {
+      const response = useData({
+        swrOptions: { revalidateOnFocus: false, ...input?.swrOptions },
+      })
+
+      return useMemo(
+        () =>
+          Object.create(response, {
+            isEmpty: {
+              get() {
+                return (response.data?.lineItems.length ?? 0) <= 0
+              },
+              enumerable: true,
+            },
+          }),
+        [response]
+      )
+    },
+}