微信小程序用setData更新数组里的值

markers: [{
      title: "",
      id: "",
      latitude: "",
      longitude: "",
      iconPath: "img/Local.png",
      width: 20,
      height: 20
    }]

 var lat = "that.markers[0].lat";
 var lng = "that.markers[0].lng";

that.setData({
          //经纬度赋值
          [lat]:res.latitude,
          [lng]:res.longitude
        })