fix: pass currency in header in AddPromotion (#67)

Author: ellanan

src/endpoints/cart.js

@@ -202,14 +202,26 @@ class CartEndpoint extends BaseExtend {
     })
   }
 
-  AddPromotion(code, token = null) {
-    const body = buildCartItemData(code, null, 'promotion_item')
+  AddPromotion(code, token=null, currency = null) {
+
+    const additionalHeaders = currency
+      ? { 'X-MOLTIN-CURRENCY': currency }
+      : {}
 
     return this.request.send(
       `${this.endpoint}/${this.cartId}/items`,
       'POST',
-      body,
-      token
+      {
+        data: {
+          type: 'promotion_item',
+          code
+        }
+      },
+      token,
+      null,
+      null,
+      null,
+      additionalHeaders
     )
   }
 

src/types/cart.d.ts

@@ -350,15 +350,6 @@ export interface CartEndpoint
     ShippingGroup: CartShippingGroupBase
   ): Promise<ShippingGroupResponse>
 
-  /**
-   * Add Promotion to Cart
-   * Description: You can use the Promotions API to apply discounts to your cart as a special cart item type.
-   * DOCS: https://documentation.elasticpath.com/commerce-cloud/docs/api/carts-and-orders/carts/add-promotion-to-cart.html
-   * @param code the promotion code.
-   * @param token a customer token to apply customer specific promotions.
-   */
-  AddPromotion(code: string, token?: string): Promise<CartItemsResponse>
-
   /**
    * Get a Cart by reference
    * DOCS: https://documentation.elasticpath.com/commerce-cloud/docs/api/carts-and-checkout/carts/get-a-cart.html
@@ -438,8 +429,10 @@ export interface CartEndpoint
    * Description: You can use the Promotions API to apply discounts to your cart as a special cart item type.
    * DOCS: https://documentation.elasticpath.com/commerce-cloud/docs/api/carts-and-orders/carts/add-promotion-to-cart.html
    * @param code the promotion code.
+   * @param token a customer token to apply customer specific promotions.
+   * @param currency the currency to apply the promotion in.
    */
-  AddPromotion(code: string): Promise<CartItemsResponse>
+  AddPromotion(code: string, token?: string, currency?: string): Promise<CartItemsResponse>
 
   /**
    * Remove promotion from Cart