我想判断polyline是否存在,存在 map.remove(polyline) 重新绘制,没找到方法,我绑定在我的

    $(document).on('click', '#workdata div', function(e) {
                var $this = $(this);
    $this.addClass("drone-right-body-yi container-search-choose")
         var workid=$(e.target).attr("id"); 
           $.getJSON("/api/getdronelistpath/"+str+"?workid="+workid, function(data) {
              for (var i = 0, len = data.length; i < len; i++) {
                      var path=data[i].path;
                      var lineArr = new Array();
                      lineArr.push(path);
                      var lineArr = path;
                var polyline = new AMap.Polyline({
                      path: lineArr,          
                      strokeColor: "#DC143C", 
                      strokeOpacity: 0.8,      
                      strokeWeight: 3,        
                      strokeStyle: "solid",   //dashed
                      strokeDasharray: [10, 0]
                      });
                     map.setZoom(19);
                     map.setCenter(data[i].path[0]);
                     new AMap.Marker({
                     map: map,
                     position: data[i].path[0],
                     icon: new AMap.Icon({            
                     size: new AMap.Size(48, 48),  
                     image: "/static/img/start.png",
                     imageOffset: new AMap.Pixel(-2, 0)
                     })        
                     });
                     new AMap.Marker({
                     map: map,
                     position: data[i].path[path.length-1],
                     icon: new AMap.Icon({            
                     size: new AMap.Size(48, 48),  
                     image: "/static/img/end.png",
                     imageOffset: new AMap.Pixel(-2, 0)
                     })        
                     });
                    polyline.setMap(map);
              } 
            })
            map.remove(polyline);//管用可以移除
                if($this.siblings(".container-search-choose").length>0){
                    $this.siblings(".container-search-choose").addClass("drone-right-body-yi").removeClass("container-search-choose");
                    console.log(map)
                    //console.log(map)输出结果{_amap_id: 3, id: 3, CLASS_NAME: "AMap.Map", ho: true, C: div#container-map.amap-container, …}
                    map.remove(polyline);//无法移除 提示  Uncaught ReferenceError: remove is not defined
                }
          })