fix(medusa-payment-klarna): Fix division by zero on free shipping (#1840)

.changeset/stale-coats-guess.md

@@ -0,0 +1,5 @@
+---
+"medusa-payment-klarna": patch
+---
+
+Bug fixed where the free shipping tax rate was incorrect due to division by zero.

integration-tests/api/__tests__/admin/__snapshots__/price-list.js.snap

@@ -75,7 +75,7 @@ Object {
   "ends_at": "2022-12-31T00:00:00.000Z",
   "id": "pl_no_customer_groups",
   "name": "Loyalty Reward - Winter Sale",
-  "prices": Array [
+  "prices": ArrayContaining [
     Object {
       "amount": 100,
       "created_at": Any<String>,

integration-tests/api/__tests__/admin/price-list.js

@@ -471,7 +471,7 @@ describe("/admin/price-lists", () => {
         status: "draft",
         starts_at: "2022-09-01T00:00:00.000Z",
         ends_at: "2022-12-31T00:00:00.000Z",
-        prices: [
+        prices: expect.arrayContaining([
           {
             id: expect.any(String),
             amount: 100,
@@ -483,6 +483,7 @@ describe("/admin/price-lists", () => {
             region_id: null,
             created_at: expect.any(String),
             updated_at: expect.any(String),
+            deleted_at: null,
           },
           {
             id: expect.any(String),
@@ -495,6 +496,7 @@ describe("/admin/price-lists", () => {
             region_id: null,
             created_at: expect.any(String),
             updated_at: expect.any(String),
+            deleted_at: null,
           },
           {
             id: expect.any(String),
@@ -507,6 +509,7 @@ describe("/admin/price-lists", () => {
             region_id: null,
             created_at: expect.any(String),
             updated_at: expect.any(String),
+            deleted_at: null,
           },
           {
             id: expect.any(String),
@@ -534,7 +537,7 @@ describe("/admin/price-lists", () => {
             updated_at: expect.any(String),
             deleted_at: null,
           },
-        ],
+        ]),
         customer_groups: [
           {
             id: "customer-group-1",

packages/medusa-payment-klarna/src/services/klarna-provider.js

@@ -76,30 +76,34 @@ class KlarnaProviderService extends PaymentService {
       const name = []
       let total = 0
       let tax = 0
+      let taxRate = 0
 
-      for (const next of cart.shipping_methods) {
-        const totals = await this.totalsService_.getShippingMethodTotals(
-          next,
-          cart,
-          {
-            include_tax: true,
-          }
-        )
+      if (cart.shipping_total > 0) {
+        for (const next of cart.shipping_methods) {
+          const totals = await this.totalsService_.getShippingMethodTotals(
+            next,
+            cart,
+            {
+              include_tax: true,
+            }
+          )
 
-        name.push(next?.shipping_option.name)
-        total += totals.total
-        tax += totals.tax_total
+          const methodTaxRate =
+            totals.tax_lines.reduce((acc, next) => acc + next.rate, 0) / 100
+
+          name.push(next?.shipping_option.name)
+          taxRate += (totals.total / cart.shipping_total) * methodTaxRate
+          tax += totals.tax_total
+        }
       }
 
-      const taxRate = tax / (total - tax)
-
       order_lines.push({
         name: name?.join(" + ") || "Shipping fee",
         quantity: 1,
         type: "shipping_fee",
         unit_price: total,
         tax_rate: taxRate * 10000,
-        total_amount: total,
+        total_amount: cart.shipping_total,
         total_tax_amount: tax,
       })
     }