js绑定table数据，合并列

要求效果
一开始一直没想到咋写，因为数据格式项名称是一个数组，脑袋转不过来，不知道循环第二个数组时如何还让第一个循环正常走；
解决：

let totalIndex = 1;
var htmlList="";
 for (var i = 0; i < listOld.length; i++) {
        var item = listOld[i];
        for (var j = 0; j < item.DeductPointList.length; j++) {
            if (j == 0) {
                htmlList += '<tr>';
                htmlList += '<td>' + totalIndex + '</td>';
                htmlList += '<td rowspan="' + item.DeductPointList.length + '">' + item.DeductItemName + '</td>';//这里重点
                htmlList += '<td>' + item.DeductPointList[j].DeductPoint + '</td>'; 
                htmlList += '<td class="score_td">-' + item.DeductPointList[j].Score + '</td>';
                htmlList += '<td><span class="cz_bj" οnclick="addNew(' + item.DeductItem_Code + ')">编辑</span><span class="cz_sc" οnclick="deteleFun(' + item.DeductItem_Code + ',' + item.DeductPointList[j].DeductPointCode+')">删除</span></td>';
                htmlList += '</tr>';
            }
            else {
                htmlList += '<tr>';
                htmlList += '<td>' + totalIndex + '</td>';
                htmlList += '<td>' + item.DeductPointList[j].DeductPoint + '</td>';
                htmlList += '<td class="score_td">-' + item.DeductPointList[j].Score + '</td>';
                htmlList += '<td><span class="cz_bj" οnclick="addNew(' + item.DeductItem_Code + ')">编辑</span><span class="cz_sc" οnclick="deteleFun(' + item.DeductItem_Code + ',' + item.DeductPointList[j].DeductPointCode +')">删除</span></td>';
                htmlList += '</tr>';
            }
            totalIndex++;
        }
    }
    $('#contentBox tbody').html(htmlList)