修改场景销毁组件不销毁的问题

src/core/viewer/Viewer.js

 import { DomUtil } from '../utils'
 import Transform from '../transform/Transform'
 import Parse from '../parse/Parse'
-import Widgets from '../widget'
+import createWidgets from '../widget'
 
 const { Cesium } = DC.Namespace
 
     /**
      * Registers default widgets
      */
-    Object.keys(Widgets).forEach(key => {
-      this.use(Widgets[key])
+    let widgets = createWidgets()
+    Object.keys(widgets).forEach(key => {
+      this.use(widgets[key])
     })
   }
 

src/core/widget/index.js

 /**
- * @Author: Caven
- * @Date: 2020-03-05 21:53:35
+ * @Author:Caven
+ * @Date:2020-03-05 21:53:35
  */
 
 import Attribution from './Attribution'
 import DistanceLegend from './DistanceLegend'
 import ZoomController from './ZoomController'
 
-const Widgets = {
-  attribution: new Attribution(),
-  popup: new Popup(),
-  contextMenu: new ContextMenu(),
-  tooltip: new Tooltip(),
-  mapSwitch: new MapSwitch(),
-  mapSplit: new MapSplit(),
-  locationBar: new LocationBar(),
-  hawkeyeMap: new HawkeyeMap(),
-  compass: new Compass(),
-  distanceLegend: new DistanceLegend(),
-  zoomController: new ZoomController()
+export default function createWidgets() {
+  return {
+    attribution: new Attribution(),
+    popup: new Popup(),
+    contextMenu: new ContextMenu(),
+    tooltip: new Tooltip(),
+    mapSwitch: new MapSwitch(),
+    mapSplit: new MapSplit(),
+    locationBar: new LocationBar(),
+    hawkeyeMap: new HawkeyeMap(),
+    compass: new Compass(),
+    distanceLegend: new DistanceLegend(),
+    zoomController: new ZoomController()
+  }
 }
-
-export default Widgets