return empty op instead of throw

Author: lopert

functions-discount-js/src/cart_delivery_options_discounts_generate_run.liquid

@@ -17,7 +17,7 @@ import {
 export function cartDeliveryOptionsDiscountsGenerateRun(input) {
   const firstDeliveryGroup = input.cart.deliveryGroups[0];
   if (!firstDeliveryGroup) {
-    throw new Error("No delivery groups found");
+    return {operations: []};
   }
 
   const hasShippingDiscountClass = input.discount.discountClasses.includes(
@@ -68,7 +68,7 @@ export function cartDeliveryOptionsDiscountsGenerateRun(
 ): CartDeliveryOptionsDiscountsGenerateRunResult {
   const firstDeliveryGroup = input.cart.deliveryGroups[0];
   if (!firstDeliveryGroup) {
-    throw new Error("No delivery groups found");
+    return {operations: []};
   }
 
   const hasShippingDiscountClass = input.discount.discountClasses.includes(

functions-discount-js/src/cart_lines_discounts_generate_run.liquid

@@ -18,7 +18,7 @@ import {
 
 export function cartLinesDiscountsGenerateRun(input) {
   if (!input.cart.lines.length) {
-    throw new Error('No cart lines found');
+    return {operations: []};
   }
 
   const hasOrderDiscountClass = input.discount.discountClasses.includes(
@@ -110,7 +110,7 @@ export function cartLinesDiscountsGenerateRun(
   input: CartInput,
 ): CartLinesDiscountsGenerateRunResult {
   if (!input.cart.lines.length) {
-    throw new Error('No cart lines found');
+    return {operations: []};
   }
 
   const hasOrderDiscountClass = input.discount.discountClasses.includes(

functions-discount-js/tests/fixtures/cart-lines-no-lines.json

@@ -0,0 +1,17 @@
+{
+  "payload": {
+    "export": "cart-lines-discounts-generate-run",
+    "target": "cart.lines.discounts.generate.run",
+    "input": {
+      "cart": {
+        "lines": []
+      },
+      "discount": {
+        "discountClasses": ["ORDER", "PRODUCT"]
+      }
+    },
+    "output": {
+      "operations": []
+    }
+  }
+}