rf3main/common/helpers/TreeHelper.php

<?php

namespace common\helpers;

/**
 * Class TreeHelper
 * @package common\helpers
 * @author jianyan74 <751393839@qq.com>
 */
class TreeHelper
{
    /**
     * @return string
     */
    public static function prefixTreeKey($id)
    {
        return  $id . '-';
    }

    /**
     * @return string
     */
    public static function defaultTreeKey()
    {
        return '0-';
    }
}