fixes to create new products

src/Product.ts

@@ -128,7 +128,9 @@ export class Product {
     let sps = new ShopifyProductSetInput()
     //TODO: map category IDs
     //sps.category = this.category
+    if (this.shopify_id != "") {
       sps.id = this.shopify_id
+    }
     if (this.shopify_status.match('DRAFT|ACTIVE|ARCHIVED')) {
       sps.status = this.shopify_status
     }
@@ -139,7 +141,9 @@ export class Product {
     sps.variants = []
     let variant = new ShopifyVariant()
     //TODO: handle multiple variants
+    if (this.shopify_default_variant_id != "") {
       variant.id = this.shopify_default_variant_id
+    }
     variant.sku = this.sku
     variant.price = this.price
     sps.variants.push(variant)

src/shopifyApi.ts

@@ -847,7 +847,7 @@ export class ShopifyProductSetQuery {
 export class ShopifyProductSetInput {
   category: string
   descriptionHtml: string
-  id: string
+  id?: string
   productType: string
   redirectNewHandle: boolean = true
   status: string = "DRAFT"