.split working in Script Editor "Run Script" but not in cart preview

Technical Q&A
1

We’ve included code that will discount a specified product when the user exceeds $50.00 in their cart. This works when the user only has one of the promo items in their cart, the promo item is fully discounted. However, when the user increases the quantity of the promo item, the promo item is no longer discounted at all – in our script below, we have a split function that recognizes a quantity > 1 and should split off the promo product into its own line item and discount a single promo item.

In the “Run Script” box of the Script Editor app – this works as intended when you set the promo item quantity to 2 and the cart total over $50.00. However on the front-end (when you click “preview on the Online Store”) in the cart, the same functionality does not happen and the promo item is not discounted when at a quantity greater than 1.

Below is the script we are using:

FREEBIE_PRODUCT_ID = 901775294506
CART_TOTAL_FOR_DISCOUNT_APPLIED = Money.new(cents: 100) * 50

freebie_in_cart = false
cart_price_exceeds_discounted_freebie_amount = false
cost_of_freebie = Money.zero

# Test if the freebie is in the cart, also get its cost if it is so we can deduct from the cart total
Input.cart.line_items.select do |line_item|
  product = line_item.variant.product
  if product.id == FREEBIE_PRODUCT_ID
    freebie_in_cart = true
    cost_of_freebie = line_item.line_price
  end
end

# If the freebie exists in the cart, check the subtotal of the other items to see if the freebie should be discounted
if freebie_in_cart
  cart_subtotal_minus_freebie_cost = Input.cart.subtotal_price - cost_of_freebie
  if cart_subtotal_minus_freebie_cost >= CART_TOTAL_FOR_DISCOUNT_APPLIED
    cart_price_exceeds_discounted_freebie_amount = true
  end
end

# Only true if the freebie is in the cart
was_discount_applied = false
if cart_price_exceeds_discounted_freebie_amount
  Input.cart.line_items.each do |item|
    if item.variant.product.id == FREEBIE_PRODUCT_ID && was_discount_applied == false
      if item.quantity > 1
        new_line_item = item.split(take: 1)
        new_line_item.change_line_price(Money.zero, message: '')
        Input.cart.line_items << new_line_item
        next
      else
        item.change_line_price(Money.zero, message: '')
      end
    end
  end
end
  
Output.cart = Input.cart

Thank you

2

I believe the problem is with this block:

if product.id == FREEBIE_PRODUCT_ID
    freebie_in_cart = true
    cost_of_freebie = line_item.line_price
  end

It should be using the price of the Variant, not the line_price. The line_price is the total price of the quantity * variant.price. So it should be as per below:

if product.id == FREEBIE_PRODUCT_ID
    freebie_in_cart = true
    cost_of_freebie = line_item.variant.price
  end