is_post_type function

function is_post_type($post_type = '', $item = '') {
    global $wp_query;
    $type_obj = $wp_query->get_queried_object();
    $post_type = (array) $post_type;

    if( in_array( $type_obj->post_type, $post_type ) && empty( $item ) )
        return true;

    if( in_array( $type_obj->post_type, $post_type ) ) {
        $item = (array) $item;

        if ( in_array( $type_obj->ID, $item ) )
            return true;
        if ( in_array( $type_obj->post_title, $item ) )
            return true;
        if ( in_array( $type_obj->post_name, $item ) )
            return true;
    }

    return false;
}