js 将数字转换成中文大写

//完成将 toChineseNum， 可以将数字转换成中文大写的表示，处理到万级别，例如 toChineseNum(12345)，返回 一万二千三百四十五。
        const toChinesNum = (num) => {
            let changeNum = ['零', '一', '二', '三', '四', '五', '六', '七', '八', '九']; //changeNum[0] = "零"
            let unit = ["", "十", "百", "千", "万"];
            num = parseInt(num);
            let getWan = (temp) => {
                let strArr = temp.toString().split("").reverse();
                let newNum = "";
                for (var i = ; i < strArr.length; i++) {
                    newNum = (i ==  && strArr[i] ==  ? "" : (i >  && strArr[i] ==  && strArr[i - ] ==  ? "" : changeNum[strArr[i]] + (strArr[i] ==  ? unit[] : unit[i]))) + newNum;
                }
                return newNum;
            }
            let overWan = Math.floor(num / );
            let noWan = num % ;
            if (noWan.toString().length < ) noWan = "" + noWan;
            return overWan ? getWan(overWan) + "万" + getWan(noWan) : getWan(num);

        }