diff --git a/src/internal/fetch/index.ts b/src/internal/fetch/index.ts
index 451dd32..a61e597 100644
--- a/src/internal/fetch/index.ts
+++ b/src/internal/fetch/index.ts
@@ -84,7 +84,10 @@ export async function $fetch<T>(options: FetchOptions, needApiKey = true) {
     Object.assign(response, { error: error as Error });
   }
 
-  response.error && onError?.(response.error);
+  if (response.error) {
+    onError?.(response.error);
+  }
+
   return response as FetchResponse<T>;
 }
 
diff --git a/test/index.test.ts b/test/index.test.ts
index 110f986..1cf8a93 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -41,6 +41,7 @@ describe("Export", () => {
       "getOrder",
       "listOrders",
       "generateOrderInvoice",
+      "issueOrderRefund",
 
       // Order Items
       "getOrderItem",
@@ -56,6 +57,7 @@ describe("Export", () => {
       "getSubscriptionInvoice",
       "listSubscriptionInvoices",
       "generateSubscriptionInvoice",
+      "issueSubscriptionInvoiceRefund",
 
       // Subscriptions Items
       "getSubscriptionItem",
diff --git a/test/products/index.test.ts b/test/products/index.test.ts
index f711ab6..3d4eca0 100644
--- a/test/products/index.test.ts
+++ b/test/products/index.test.ts
@@ -145,8 +145,8 @@ describe("Retrieve a product", () => {
     const { id, type, attributes, relationships } = data;
     expect(id).toEqual(productId.toString());
     expect(type).toEqual(DATA_TYPE);
-    expect(attributes).toBeDefined;
-    expect(relationships).toBeDefined;
+    expect(attributes).toBeDefined();
+    expect(relationships).toBeDefined();
 
     const {
       store_id,
@@ -222,8 +222,8 @@ describe("Retrieve a product", () => {
     const { id, type, attributes, relationships } = data;
     expect(id).toEqual(productId.toString());
     expect(type).toEqual(DATA_TYPE);
-    expect(attributes).toBeDefined;
-    expect(relationships).toBeDefined;
+    expect(attributes).toBeDefined();
+    expect(relationships).toBeDefined();
 
     const {
       store_id,
diff --git a/test/subscriptions/index.test.ts b/test/subscriptions/index.test.ts
index cdb4bbd..c7e04c9 100644
--- a/test/subscriptions/index.test.ts
+++ b/test/subscriptions/index.test.ts
@@ -39,7 +39,7 @@ describe("List all subscriptions", () => {
 
     // Get active subscription
     const activeSubscription = data.find((d) => {
-      d.attributes.status === "active";
+      return d.attributes.status === "active";
     });
 
     const { id, attributes } = activeSubscription ?? data[0];