qimall/addons/WangDianTong/common/helper/EmojiHelper.php

<?php

namespace addons\WangDianTong\common\helper;

class EmojiHelper
{

    /**
     * @param string $str
     * @return string
     */
    public static function convert(string $str): string
    {
        $mbLen = mb_strlen($str);
        if ($mbLen > 0) {
            $strArr = [];
            for ($i = 0; $i < $mbLen; $i++) {
                $mbSubstr = mb_substr($str, $i, 1, 'utf-8');
                if (strlen($mbSubstr) >= 4) {
//                    $strArr[] = '*';
                } else {
                    $strArr[] = $mbSubstr;
                }
            }
            if (!empty($strArr)) return implode('', $strArr);
        }
        return '';
    }
}