GA4 Purchase

<script>
dataLayer.push({ ecommerce: null });  // Clear the previous ecommerce object.
dataLayer.push({
  event: "purchase",
  ecommerce: {
      transaction_id: "T_12345",                // This is the order ID that's shown on the TY page to the user upon successful purchase
      affiliation: "Google Merchandise Store",
      value: 25.42,
      tax: 4.90,
      shipping: 5.99,
      currency: "USD",
      coupon: "SUMMER_SALE",
      items: [
       {
        item_id: "SKU_12345",
        item_name: "Stan and Friends Tee",
        affiliation: "Google Merchandise Store",
        coupon: "SUMMER_FUN",
        currency: "USD",
        discount: 2.22,
        index: 0,
        item_brand: "Google",
        item_category: "Apparel",
        item_category2: "Adult",
        item_category3: "Shirts",
        item_category4: "Crew",
        item_category5: "Short sleeve",
        item_list_id: "related_products",
        item_list_name: "Related Products",
        item_variant: "green",
        location_id: "L_12345",
        price: 9.99,
        quantity: 1
      },
      {
        item_id: "SKU_12346",
        item_name: "Google Grey Women's Tee",
        affiliation: "Google Merchandise Store",
        coupon: "SUMMER_FUN",
        currency: "USD",
        discount: 3.33,
        index: 1,
        item_brand: "Google",
        item_category: "Apparel",
        item_category2: "Adult",
        item_category3: "Shirts",
        item_category4: "Crew",
        item_category5: "Short sleeve",
        item_list_id: "related_products",
        item_list_name: "Related Products",
        item_variant: "gray",
        location_id: "L_12345",
        price: 20.99,
        promotion_id: "P_12345",
        promotion_name: "Summer Sale",
        quantity: 1
      }]
  }
});
</script>