Remove checkout field if product IDs exist. WooCommerce / WordPress

functions.php

<?php
/**
 * Conditionally remove a checkout field based on products in the cart
 */
function wc_ninja_remove_checkout_field( $fields ) {
	if ( ! wc_ninja_product_is_in_the_cart() ) {
		unset( $fields['billing']['billing_company'] );
	}

	return $fields;
}
add_filter( 'woocommerce_checkout_fields' , 'wc_ninja_remove_checkout_field' );