Mandatory custom radio button choice on Woocommerce checkout - wordpress

Question

I've got this custom code working to add a couple of radio buttons into the checkout:
add_action( 'woocommerce_review_order_before_payment', 'display_extra_fields_after_billing_address' , 10, 1 );
function display_extra_fields_after_billing_address () { ?>
<h3 class="delivery-options-heading">Delivery Options <sup>*</sup></h3>
<div class="delivery-options">
<p><input type="radio" name="delivery_option" value="Have the courier leave a card." required /> Have the courier leave a card.</p>
<p><input type="radio" name="delivery_option" value="Leave the consignment without a signature." required /> Leave the consignment without a signature.</p>
</div>
<?php
}
add_action( 'woocommerce_checkout_update_order_meta', 'add_delivery_option_to_order' , 10, 1);
function add_delivery_option_to_order ( $order_id ) {
if ( isset( $_POST ['delivery_option'] ) && '' != $_POST ['delivery_option'] ) {
add_post_meta( $order_id, '_delivery_option', sanitize_text_field( $_POST ['delivery_option'] ) );
}
}
add_filter( 'woocommerce_email_order_meta_fields', 'add_delivery_option_to_emails' , 10, 3 );
function add_delivery_option_to_emails ( $fields, $sent_to_admin, $order ) {
if( version_compare( get_option( 'woocommerce_version' ), '3.0.0', ">=" ) ) {
$order_id = $order->get_id();
} else {
$order_id = $order->id;
}
$delivery_option = get_post_meta( $order_id, '_delivery_option', true );
if ( '' != $delivery_option ) {
$fields[ 'Delivery Date' ] = array(
'label' => __( 'Delivery Option', 'delivery_option' ),
'value' => $delivery_option,
);
}
return $fields;
}
Every part of this works fine except for the required attributes on the radio buttons, letting the user checkout without making a choice, which is not ideal. For some reason the required attributes are being ignored.
How can I force the user to select one of the radio buttons before checking out?

Answer 1

Please add this validation hook along with your code that will validate your option on checkout
function action_woocommerce_after_checkout_validation( $data, $errors ) {
if( !isset( $data['delivery_option'] ) || empty( $data['delivery_option'] ) ) :
$errors->add( 'required-field', __( 'No delivery option has been selected. Please choose delivery option.', 'woocommerce' ) );
endif; //Endif
}
// add the action
add_action( 'woocommerce_after_checkout_validation', 'action_woocommerce_after_checkout_validation', 10, 2 );

Answer 2

This was the solution, slightly different to what Krunal Prajapati suggested. The only difference is the second line:
function action_woocommerce_after_checkout_validation( $data, $errors ) {
if ( empty( $_POST['delivery_option'] ) ) :
$errors->add( 'required-field', __( 'No delivery option has been selected. Please choose delivery option.', 'woocommerce' ) );
endif; //Endif
}
// add the action
add_action( 'woocommerce_after_checkout_validation', 'action_woocommerce_after_checkout_validation', 10, 2 );