added use submit discount code

frontend/composables/api/orders/useSubmitDiscountCode.ts

@@ -0,0 +1,37 @@
+// imports
+
+import { useMutation } from "@tanstack/vue-query";
+import { API_ENDPOINTS } from "~/constants";
+
+// types
+
+export type SubmitDiscountCodeRequest = {
+    code: string;
+};
+
+const useSubmitDiscountCode = () => {
+    // state
+
+    const { $axios: axios } = useNuxtApp();
+
+    // methods
+
+    const handleSubmitDiscountCode = async (
+        params: SubmitDiscountCodeRequest
+    ) => {
+        const { data } = await axios.post(
+            API_ENDPOINTS.orders.cart.add_discount,
+            {
+                ...params,
+            }
+        );
+        return data;
+    };
+
+    return useMutation({
+        mutationFn: (discountData: SubmitDiscountCodeRequest) =>
+            handleSubmitDiscountCode(discountData),
+    });
+};
+
+export default useSubmitDiscountCode;