Price is undefined

When the “Purchase” events fires (thankyou page after you make an order)

And you use a coupon (smart coupons) the gives you the order for free.

so technically the price is 0

then the price in the data layer is undefined which gives us problems with GTM

example:

{
"event": "purchase",
"ecommerce": {
"currency": "EUR",
"items": [
{
"item_id": "43534534534543543",
"item_name": "Kerstlampjes (20 LED lampjes)",
"item_brand": "Kerstcollectie",
"price": ,
"item_category": "Decoratie",
"quantity": 1,
"google_business_vertical": "retail",
"id": "43534534534543543"
}
],
"transaction_id": "435345345",
"affiliation": "",
"value": 0,
"tax": 0,
"shipping": 0,
"coupon": "somecouponthatgivesmethatorderforfree"
}
}

What i did to solvew it for now but is not really prefered as it is hardcoded fix.

gtm4wp-woocommerce-enhanced.js // line 24

'price': productdata.price ? productdata.price : ""

versus

'price': productdata.price ? productdata.price : "0.00"

Now it solves our problem