Updating Options of Flexslider in Wordpress

Flexslider has before function Fires asynchronously with each slider animation

//before: function(){}, //Callback: function(slider)

Trying to update its options at functions.php but callback api functions are not working

add_filter('woocommerce_single_product_carousel_options', 'ud_update_woo_flexslider_options');

function ud_update_woo_flexslider_options( $options ) {

      $options['slideshow'] = true; // It works

    **$options['before'] = "function(slider){alert('something')}";** // Not working

    return $options;
}