How to Update/Override Core form Validation in magento 2?

Question

I want to override or update core validation for magento frontend form like as checkout page form address field validation change.

need to change the core validation

Answer 1

You must use this:

1) In input or select tag add our validaion with this code

data-validate="{required:true, 'validate-custom-name':true}"

2) Add js validation for “Validate-custom-name”

<script type="text/javascript">
require(['jquery', // jquery Library
    'jquery/ui', // Jquery UI Library
    'jquery/validate', // Jquery Validation Library
    'mage/translate' // Magento text translate (Validation message translte as per language)
], function($) {
    $.validator.addMethod('validate-custom-name', function(value) {
        return (value !== 'test'); // Validation logic here
    }, $.mage.__('Enter Valid name'));
});
</script>