Display Only Selected Countries on the Vendor Registration Form

add_action(

    'wp_enqueue_scripts',

    static function () {

        $registration_page_id = (int) get_option( 'wcv_signup_registration_page_id', 0 );

        if ( 0 === $registration_page_id || ! is_page( $registration_page_id ) ) {

            return;

        }

        $allowed_countries = array( 'AU', 'GB', 'US', 'CA' ); // ISO 3166-1 alpha-2 codes

        if ( empty( $allowed_countries ) ) {

            return;

        }

        wp_enqueue_script( 'wcv-signup' );

        wp_add_inline_script(

            'wcv-signup',

            sprintf(

                "window.addEventListener('load',function(){var allowed=%s,form=document.getElementById('wcv-registration-form');if(!form){return;}var select=form.querySelector('select[name=\"country\"]');if(!select){return;}Array.from(select.options).forEach(function(opt){if(opt.value && -1===allowed.indexOf(opt.value)){opt.remove();}});if(select.options.length&&allowed.indexOf(select.value)===-1){select.value=allowed[0];}select.dispatchEvent(new Event('change',{bubbles:true}));});",

                wp_json_encode( array_values( array_unique( $allowed_countries ) ) )

            ),

            'after'

        );

    },

    30

);