WC API v3 - add functionality to filter by order_currency

wc-api-add-oder-currency-filter.txt

/**
 * WC API v3 - add functionality to filter by order_currency
 * example request: /wp-json/wc/v3/orders?status=processing&per_page=-1&currency=EUR
 */

add_filter( 'woocommerce_rest_orders_prepare_object_query', 'theme_woocommerce_rest_orders_prepare_object_query', 10, 2 );
function theme_woocommerce_rest_orders_prepare_object_query( $args, $request ){

    $args['meta_query'][] = array(
        'key'   => '_order_currency',
        'value' => $request['currency'],
        'compare' => 'LIKE'
    );

    return $args;
}