Hide shipping rates when free shipping is available

hide-shipping-fee.php

/**
 * @snippet  Hide shipping rates when free shipping is available.
 * @author   JJMontalban     
 */
function my_hide_shipping_when_free_is_available( $rates ) {
	$free = array();
	foreach ( $rates as $rate_id => $rate ) {
	if ( 'free_shipping' === $rate->method_id ) {
	$free[ $rate_id ] = $rate;
	break;
	}
	}
	return ! empty( $free ) ? $free : $rates;
   }
   add_filter( 'woocommerce_package_rates', 'my_hide_shipping_when_free_is_available', 100 );