Conditionally Required WooCommerce Checkout Field - php

Question

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eMikkelsen wants to draw more attention to this question:
Help me adjust the above code so that the field is not only conditional in terms of when to show but also in terms of when it is required. It must be required when the COD payment is chosen but otherwise not.
I want to make a WooCommerce Checkout Field that only shows up when a specific payment (Cash On Delivery) is chosen. This field should only show up and only be required when cash on delivery is chosen. I have managed to make the field and have it show up conditionally, but I cannot figure out how to make it required only when COD is chosen.
/* Only show EAN when COD chosen */
// Conditional Show hide checkout fields based on chosen payment methods
add_action( 'wp_footer', 'conditionally_show_hide_billing_custom_field' );
function conditionally_show_hide_billing_custom_field(){
// Only on checkout page
if ( is_checkout() && ! is_wc_endpoint_url() ) :
?>
<script>
jQuery(function($){
var a = 'input[name="payment_method"]',
b = a + ':checked',
c = '#billing_options_field'; // The checkout field <p> container selector
// Function that shows or hide checkout fields
function showHide( selector = '', action = 'show' ){
if( action == 'show' )
$(selector).show( 200, function(){
$(this).addClass("validate-required");
});
else
$(selector).hide( 200, function(){
$(this).removeClass("validate-required");
});
$(selector).removeClass("woocommerce-validated");
$(selector).removeClass("woocommerce-invalid woocommerce-invalid-required-field");
}
// Initialising: Hide if choosen payment method is "cod"
if( $(b).val() !== 'cod' )
showHide( c, 'hide' );
else
showHide( c );
// Live event (When payment method is changed): Show or Hide based on "cod"
$( 'form.checkout' ).on( 'change', a, function() {
if( $(b).val() !== 'cod' )
showHide( c, 'hide' );
else
showHide( c );
});
});
</script>
<?php
endif;
}
/* Add extra field and make it required */
add_filter('woocommerce_billing_fields', 'custom_woocommerce_billing_fields');
function custom_woocommerce_billing_fields($fields)
{
$fields['billing_options'] = array(
'label' => __('– EAN-nummer – ', 'woocommerce'), // Add custom field label
'placeholder' => _x('EAN nummer', 'placeholder', 'woocommerce'), // Add custom field placeholder
'required' => true, // if field is required or not
'clear' => false, // add clear or not
'type' => 'text', // add field type
'class' => array('my-css') // add class name
);
return $fields;
}

Answer 1

add_action('woocommerce_after_checkout_validation', 'woocommerce_after_checkout_validation_alter', 10, 2);
function woocommerce_after_checkout_validation_alter($data, $errors){
if('cod' !== $data['payment_method']){
if($errors->get_error_data('billing_options_required')){ // This will contain the error
$errors->remove('billing_options_required');
}
}
return $data;
}
Remove the validation error from the error object if the payment method selected is not COD. The error object will be like the below.
WP_Error Object
(
[errors] => Array
(
[billing_options_required] => Array
(
[0] => <strong>Billing – EAN-nummer – </strong> is a required field.
)
)
[error_data] => Array
(
[billing_options_required] => Array
(
[id] => billing_options
)
)
[additional_data:protected] => Array
(
)
)