* @snippet       Hide ALL shipping rates in ALL zones when Free Shipping is available
 * @how-to        Get CustomizeWoo.com FREE
 * @sourcecode    https://businessbloomer.com/?p=260
 * @author        Rodolfo Melogli
 * @compatible    WooCommerce 3.6.3
 * @donate $9     https://businessbloomer.com/bloomer-armada/
 */
  
add_filter( 'woocommerce_package_rates', 'bbloomer_unset_shipping_when_free_is_available_all_zones', 10, 2 );
   
function bbloomer_unset_shipping_when_free_is_available_all_zones( $rates, $package ) {
      
$all_free_rates = array();
     
foreach ( $rates as $rate_id => $rate ) {
      if ( 'free_shipping' === $rate->method_id ) {
         $all_free_rates[ $rate_id ] = $rate;
         break;
      }
}
     
if ( empty( $all_free_rates )) {
        return $rates;
} else {
        return $all_free_rates;
} 
 
}