正则匹配 隐藏手机号中间4位

1/**
2 * 隐藏手机号中间4位
3 * @param $mobile
4 * @return string|string[]|null
5 */
6final protected function hideMobilePhoneNumber($mobile)
7{
8    $IsWhat = preg_match('/(0[0-9]{2,3}[\-]?[2-9][0-9]{6,7}[\-]?[0-9]?)/i', $mobile);
9    if ($IsWhat == 1) {
10        return preg_replace('/(0[0-9]{2,3}[\-]?[2-9])[0-9]{3,4}([0-9]{3}[\-]?[0-9]?)/i', '$1****$2', $mobile);
11    } else {
12        $pattern = '/(\d{3})(\d{4})(\d{4})/i';
13        $replacement = '$1****$3';
14        return preg_replace($pattern, $replacement, $mobile);
15    }
16}