WooCommerce - Get quantity of the active selected product variation in WooCommerce

gistfile1.txt

 add_action('woocommerce_before_add_to_cart_button', 'get_selected_variation_stock', 11, 0);
            function get_selected_variation_stock() {
                global $product, $wpdb;

                // HERE set your custom message
                $message_outofstock = __('My custom "out of stock" message');

                // Get the visible product variations stock quantity
                $variations_data = array();
                $child_ids = $product->get_visible_children();
                $child_ids = implode(',', $child_ids);
                $results = $wpdb->get_results("
        SELECT p.ID, pm.meta_value as stock_qty
        FROM {$wpdb->prefix}posts as p
        INNER JOIN {$wpdb->prefix}postmeta as pm ON p.ID = pm.post_id
        WHERE p.post_type LIKE 'product_variation'
        AND p.ID IN ($child_ids) AND pm.meta_key LIKE '_stock'
    ");

                foreach ($results as $result) {
                    // Set in an indexed array for each variation ID the corresponding stock qty
                    $variations_data[$result->ID] = $result->stock_qty;
                }

                ?>
    <script>
        jQuery(document).ready(function($) {
            var vData = <?php echo json_encode($variations_data); ?>,
                stock = '.woocommerce-variation-availability > .stock';

            // Function that get the selected variation stock quantity and returns it
            function getTheStockQty(a = vData) {
                $.each(a, function(index, value) {
                    if (index == $('input.variation_id').val())
                        return value;
                });
            }

            // Once loaded (if a variation is selected by default)
            setTimeout(function() {
                var stockQty = getTheStockQty();
                if (0 < $('input.variation_id').val() && $(stock).hasClass('out-of-stock')) { // OUT OF STOCK
                    // Output a custom message for "out of stock"
                    $(stock).text('<?php echo $message_outofstock; ?>');
                    // Testing output in the browser JS console
                    console.log('(1)' + $(stock).html() + ' | Stock qty: ' + stockQty);
                } else if (0 < $('input.variation_id').val()) { // IN STOCK
                    // Testing output in the browser JS console
                    console.log('(2)' + $(stock).html() + ' | Stock qty: ' + stockQty);
                }
            }, 300);

            // On live selected variation
            $('select').blur(function() {
                var stockQty = getTheStockQty();
                if (0 < $('input.variation_id').val() && $(stock).hasClass('out-of-stock')) { // OUT OF STOCK
                    // Output a custom message for "out of stock"
                    $(stock).text('<?php echo $message_outofstock; ?>');
                    // Testing output in the browser JS console
                    console.log('(1 live)' + $(stock).html() + ' | Stock qty: ' + stockQty);
                } else if (0 < $('input.variation_id').val()) { // IN STOCK
                    // Testing output in the browser JS console
                    console.log('(2 live)' + $(stock).html() + ' | Stock qty: ' + stockQty);
                }
            });
        });
    </script>
<?php
            }