WooCommerce Add Custom Sorting 'rand' in Shop Page

functions.php

add_filter( 'woocommerce_default_catalog_orderby_options', 'ec_child_woocommerce_custom_catalog_orderby_options' );

function ec_child_woocommerce_custom_catalog_orderby_options ( $sorting ) {

    $sorting['rand'] = esc_html__( 'Random', 'electro-child' );

    return $sorting;
}