用js去拼接json

{
    "cateAttr":[
          {
            "attrName": "最大日除湿量",
            "attrVals": [],
            "attrMetas": {
              "isSukCandidate": false,
              "isUserDefined": true,
              "unit": "",
              "valueType": "STRING",
              "multi": false
            },
            "propertyId": 76837

          },
          {
            "attrName": "水箱容量 (L)",
            "attrVals": [],
            "attrMetas": {
              "isSukCandidate": false,
              "isUserDefined": true,
              "unit": "L",
              "valueType": "NUMBER",
              "multi": false
            },
            "propertyId": 78200
          }
    ],
    "spuAttr":[
        {
            "keyPropertyText":"品牌:测试;型号:bgy112.。",
            "affectPropertyText":"是否可升降:是;是否支持人体工程学:否"
        },
        {
            "keyPropertyText":"品牌:测试;型号:bgy112.。",
            "affectPropertyText":"是否可升降:是;是否支持人体工程学:否"
        }
    ]
}

//以上是后台需要我发给他的数据格式
//首先用js构建一个一样数据结构的对象
//从外到里
//然后再根据需求去遍历

        var data = {};
        var cateAttr = [];
        var spuAttr = [];

        for (var i = 0; i < $(".tab-tr").length; i++) {
            var cateObj = {};
            cateObj.attrName = "str11";
            cateObj.attrVals = [];
            cateObj.attrMetas = {
                "isSukCandidate": false,
                "isUserDefined": true,
                "multi": false
            };
            cateObj.attrMetas.unit = '';
            cateObj.attrMetas.valueType = "str12";
            cateObj.propertyId = "123";
            cateObj.attrVal = "123";
            cateAttr.push(cateObj);
        }
        data.cateAttr = cateAttr;
        if ($(".tab-trs").length<0) {
            for (var i = 0; i < $(".tab-trs").length; i++) {
                var spuObj = {};
                spuObj.keyPropertyText = "str21";
                spuObj.affectPropertyText = "str22";
                spuAttr.push(spuObj);
            }
            data.spuAttr = spuAttr;
        }
       
        //其中的变化的可以用变量动态替换
        //这个json你的动态区添加属性与值
        //console.log(JSON.stringify(data));