change title of variable woocommerce product based on attribute value selection

I want to change the Woocommerce variable product title when someone selects the varient. I want to add the selected variant to title.
I have used this Change WooCommerce variable product title based on variation code It’s working perfectly for attributes that are added from product->attributes .But i want that to work for custom product attributes which we add when adding product.

I tried the code provided in above link for that but it’s not working for custom product attributes.It returns a null value.
colorr is the name of attribue i added using custom product attributes
Here is my code.Any help will be highly appriciated

add_filter( 'wp_footer','custom_product_title_script' );
function custom_product_title_script(){
    global $post;

    // Only single product pages
    if( ! is_product() ) return;

    // get an instance of the WC_Product Object
    $product = wc_get_product($post->ID);

    // Only for variable products
    if( ! $product->is_type( 'variable' ) ) return;

    // Here set your specific product attributes in this array (coma separated):
    $attributes = array('colorr');

    // The 1st loop for variations IDs
    foreach($product->get_visible_children( ) as $variation_id ) {

        // The 2nd loop for attribute(s)/value
        foreach($product->get_available_variation( $variation_id )['attributes'] as $key => $value_id ){
            $taxonomy = str_replace( 'attribute_', '', $key ); // Get the taxonomy of the product attribute

            // Just for defined attributes
            if( in_array( $taxonomy, $attributes) ){
                // Set and structure data in an array( variation ID => product attribute => term name )
                $data[ $variation_id ][$taxonomy] = get_term_by( 'slug', $value_id, $taxonomy )->name;
            }
        }
    }

    ?>
        <script type="text/javascript">
            (function($){
                // variables initialization
                var variationsData = <?php echo json_encode($data); ?>,
                    productTitle = $('.product_title').text(),
                    color = 'colorr';
                console.log(variationsData);

                // function that get the selected variation and change title
                function update_the_title( productTitle, variationsData, color ){
                    $.each( variationsData, function( index, value ){
                        if( index == $('input.variation_id').val() ){
                            $('.product_title').text(productTitle+' - '+value[color]);
                            console.log('TITLE UPDATED');
                            return false;
                        } else {
                            $('.product_title').text(productTitle);
                        }
                    });
                }

                // Once all loaded
                setTimeout(function(){
                    update_the_title( productTitle, variationsData, color );
                }, 300);

                // On live event: select fields
                $('select').blur( function(){
                    update_the_title( productTitle, variationsData, color );
                });
            })(jQuery);
        </script>
    <?php
}