WooCommerce Snippet: Hide Shipping when Free Shipping is Available

hide_shipping_when_free_is_available.php

<?php

add_filter('woocommerce_package_rates', 'hide_shipping_when_free_is_available', 100, 2);

function hide_shipping_when_free_is_available($rates, $package) {
    $free = array();

    foreach ($rates as $rate_id => $rate) {
        if ('free_shipping' === $rate->method_id) {
            $free[$rate_id] = $rate;
            break;
        }
    }

    return !empty($free) ? $free : $rates;
}