Shopify Scripts

Free Gift.rb

# See https://onlygrowth.com/blogs/posts/17-shopify-scripts-to-maximize-conversions for some helpful snippets
class FreeGift
  def initialize(variant_id, minTotal, message, quantity = 1)
    @variant_id = variant_id
    @minTotal = minTotal
    @message = message
    @giftQuantity = quantity
  end
  
  # Get the total of the cart without the variant price being included
  def getTotalWithoutGift(cart)
    removedGift = false
    cartTotalWithoutGift = Money.zero
    
    cart.line_items.each do |item|
      # Check to see if the gift has been removed already 
      # and if the current item is the gift
      if item.variant.id == @variant_id && !removedGift
        # Ensure that we are only removing the quantity of the gift from the
        # free gift item when calculating the total without the gift
        if item.quantity > @giftQuantity
          i = @giftQuantity
          while i < item.quantity do
            cartTotalWithoutGift += item.variant.price
            i += 1
          end
        end
        # Flag that the gift has now been removed from the total
        removedGift = true
        next
      end
      
      cartTotalWithoutGift += item.line_price_was
    end
    
    return cartTotalWithoutGift
  end
  
  # Apply the free gift promotion if this gift's conditions are met
  def run(cart)
    # Flag for whether the gift has been given (price removed from total)
    giftMadeFree = false
    cartTotal = getTotalWithoutGift(cart)
    
    if cartTotal >= @minTotal
      cart.line_items.each do |item|
        break if giftMadeFree
        if item.variant.id == @variant_id
          item.change_line_price(item.line_price - (item.variant.price * @giftQuantity), message: @message)
          giftMadeFree = true
        end
      end
      
      if not giftMadeFree
        # We can't actually add products to a customer's cart with the script editor, so we need to
        # make sure that we are doing it in JS when the threshold is reached
      end
    end
  end
end

GIFTS = [
  # Give the Jewellery Carrier for purchases >=$250
  FreeGift.new(
    5338912897,
    Money.new(cents: 100) * 250,
    "Complimentary Deluxe Jewellery Carrier on purchases of $250 or more",
  ),
]

GIFTS.each do |gift|
  gift.run(Input.cart)
end

Output.cart = Input.cart