微信小程序 res.data.map is not a function

原出错代码：

function findBikes(longitude, latitude, that){
  wx.request({
    url: 'http://localhost:8080/bike/findNear',
    method:"GET",
    data:{
      longitude:longitude,
      latitude:latitude,
    },
    success:function(res){
      //console.log(res)=
      var bikes = res.data.map((bike) => {
        return {
          longitude: bike.longitude,
          latitude: bike.latitude,
          id: bike.id,
          iconPath: "/images/bike.png",
          width: 35,
          height: 40
        }
      });
      //将bike数组放到markers里
      that.setData({
        markers:bikes
      });

    }
  })
}

出错原因：
这里的data是json不是数组

修改：

var resdata = Array.from(res.data)
var bikes = resdata.map((bike) => {