add layer delegate check

modules/layer/Layer.js

@@ -134,8 +134,8 @@ class Layer {
       overlay.overlayEvent &&
       !this._cache.hasOwnProperty(overlay.overlayId)
     ) {
-      overlay.overlayEvent.fire(OverlayEventType.ADD, this)
       this._cache[overlay.overlayId] = overlay
+      this.delegate && overlay.overlayEvent.fire(OverlayEventType.ADD, this)
       if (this._state === State.CLEARED) {
         this._state = State.ADDED
       }
@@ -153,7 +153,7 @@ class Layer {
       overlay.overlayEvent &&
       this._cache.hasOwnProperty(overlay.overlayId)
     ) {
-      overlay.overlayEvent.fire(OverlayEventType.REMOVE, this)
+      this._delegate && overlay.overlayEvent.fire(OverlayEventType.REMOVE, this)
       delete this._cache[overlay.overlayId]
     }
   }

modules/layer/type/LayerGroup.js → modules/layer/LayerGroup.js

@@ -6,7 +6,7 @@
 import { Util } from '@dc-modules/utils'
 import State from '@dc-modules/state/State'
 import { LayerGroupEventType, LayerGroupEvent } from '@dc-modules/event'
-import Layer from '../Layer'
+import Layer from './Layer'
 
 class LayerGroup {
   constructor(id) {

modules/layer/index.js

@@ -5,6 +5,7 @@
 
 export { default as LayerType } from './LayerType'
 export { default as Layer } from './Layer'
+export { default as LayerGroup } from './LayerGroup'
 
 /**
  * types
@@ -16,7 +17,6 @@ export { default as HeatLayer } from './type/HeatLayer'
 export { default as HtmlLayer } from './type/HtmlLayer'
 export { default as KmlLayer } from './type/KmlLayer'
 export { default as LabelLayer } from './type/LabelLayer'
-export { default as LayerGroup } from './type/LayerGroup'
 export { default as PrimitiveLayer } from './type/PrimitiveLayer'
 export { default as TilesetLayer } from './type/TilesetLayer'
 export { default as TopoJsonLayer } from './type/TopoJsonLayer'