Moved the handlers to each hook

framework/bigcommerce/customer/use-customer.tsx

@@ -1,4 +1,25 @@
+import { HookHandler } from '@commerce/utils/types'
 import useCustomer, { UseCustomer } from '@commerce/customer/use-customer'
+import type { Customer, CustomerData } from '../api/customers'
 import type { BigcommerceProvider } from '..'
 
 export default useCustomer as UseCustomer<BigcommerceProvider>
+
+export const handler: HookHandler<Customer | null> = {
+  fetchOptions: {
+    url: '/api/bigcommerce/customers',
+    method: 'GET',
+  },
+  async fetcher({ options, fetch }) {
+    const data = await fetch<CustomerData | null>(options)
+    return data?.customer ?? null
+  },
+  useHook({ input, useData }) {
+    return useData({
+      swrOptions: {
+        revalidateOnFocus: false,
+        ...input.swrOptions,
+      },
+    })
+  },
+}