Discount - Based on Payment Terms

Dear Experts,

X Pvt Ltd Purchase of Raw Materials from Y Pvt Ltd.

Y Pvt Ltd company offer a discount, if X Pvt Ltd company process the payment for raw material on 30 days,  will give discounts 1% on basic value of goods.

I like to know that, that discount portion GST should reverse in return...?

Please share implication in view of GST

Thanks & Regards

Fareed