关于函数的封装问题...................

<!DOCTYPE html>
<html>
<body>
<p id="tel">15812345678</p>
</body>
</html>
<script type="text/javascript">
    var tel = document.getElementById('tel'),
    telVal = tel.innerText;
    var newTelVal = '';
    if(telVal.length > 0){
        for(var i = 0; i < telVal.length; i++){
            if(i < 3 || i >= telVal.length-4){
                newTelVal += telVal[i];
            }else{
                newTelVal += '*';
            }
        }
    }
    tel.innerText = newTelVal;
</script>

图片说明

麻烦大佬给这个代码封装一下类似于:

console.log(fengzhuang(15698754545)) // 156****4545

 function fengzhuang(tel){
    let newTelVal = '';
    let telNum=tel+'';
    if(telNum.length > 0){
        for(var i = 0; i < telNum.length; i++){
            if(i < 3 || i >= telNum.length-4){
                newTelVal += telNum[i];
            }else{
                newTelVal += '*';
            }
        }
    }
    return newTelVal;
    }
    console.log(fengzhuang(13555555555));