Skip free gift in discount item through script

[Jawad_Rafiq]

The script is written for a discount on the basis of the item like buy 2 items and get 20% off but when I add a gift to the cart it deal it as an item but I want to skip that gift on its count.
Like 1 item is added and 1 gift is added then there is no discount when there is 2 product and 1 gift then it should give the 20% discount as per script.
I tried line_item.variant.id but that does not work I have a variant id but dnt know how to make it check in the script.

Regards