Magento2 : Vat Field Validation on checkout page

Question

Condition is this.

VAT textfield - require field validation off when country selected is USA

VAT textfield - require field validation on when country selected is other than USA

Answer 1

it's done Using override

Magento_Checkout/web/js/shipping.js

validation working.

In this file there are different types of method related to method add jquery validation. Like method i have used : saveNewAddress and setShippingInformation.