Refresh / update minicart with AJAX in Woocommerce

I’m trying to add this code to my WooCommerce setup that adds a shopping cart link wherever I put the PHP and then updates it upon changing items in the cart with AJAX: https://docs.woocommerce.com/document/show-cart-contents-total/

Here are the snippets:

HTML - PHP:

<a class="cart-customlocation" href="<?php echo wc_get_cart_url(); ?>" title="<?php _e( 'View your shopping cart' ); ?>"><?php echo sprintf ( _n( '%d item', '%d items', WC()->cart->get_cart_contents_count() ), WC()->cart->get_cart_contents_count() ); ?> - <?php echo WC()->cart->get_cart_total(); ?></a>

In functions.php file:

function woocommerce_header_add_to_cart_fragment( $fragments ) {
    global $woocommerce;

    ob_start();

    ?>
    <a class="cart-customlocation" href="<?php echo esc_url(wc_get_cart_url()); ?>" title="<?php _e('View your shopping cart', 'woothemes'); ?>"><?php echo sprintf(_n('%d item', '%d items', $woocommerce->cart->cart_contents_count, 'woothemes'), $woocommerce->cart->cart_contents_count);?> - <?php echo $woocommerce->cart->get_cart_total(); ?></a>
    <?php
    $fragments['a.cart-customlocation'] = ob_get_clean();
    return $fragments;
}

But the AJAX is not working. Is the second snippet all I need to add to the functions.php?

It feels like I should call the function and not just define it?

Or do I need to activate AJAX in general in some way to get it to work?

The filter hook woocommerce_add_to_cart_fragments is missing from your function…

To get it work, it should be:

add_filter( 'woocommerce_add_to_cart_fragments', 'header_add_to_cart_fragment', 30, 1 );
function header_add_to_cart_fragment( $fragments ) {
    global $woocommerce;

    ob_start();

    ?>
    <a class="cart-customlocation" href="<?php echo esc_url(wc_get_cart_url()); ?>" title="<?php _e('View your shopping cart', 'woothemes'); ?>"><?php echo sprintf(_n('%d item', '%d items', $woocommerce->cart->cart_contents_count, 'woothemes'), $woocommerce->cart->cart_contents_count);?> - <?php echo $woocommerce->cart->get_cart_total(); ?></a>
    <?php
    $fragments['a.cart-customlocation'] = ob_get_clean();

    return $fragments;
}

Code goes in function.php file of your active child theme (or active theme). Untested.