Merge branch 'dev'

src/components/dropdown-list/dropdown-list.vue

@@ -196,7 +196,7 @@ export default class DropDownList extends Vue {
             val = tempVal.length >0?tempVal[0].value:null;
         }
         const type: string = this.$util.typeOf(val);
-        val = Object.is(type, 'null') || Object.is(type, 'undefined') ? undefined : val;
+        val = Object.is(type, 'null') || Object.is(type, 'undefined') ? null : val;
         this.$emit('change', val);
     }
 

src/utils/types/app-popover.d.ts

@@ -37,7 +37,7 @@ export declare interface AppPopover {
      * @param {number} [height]
      * @memberof AppPopover
      */
-    openPopover(event: MouseEvent, content: (h: CreateElement) => any, title?: string, position?: PopperJs.Placement, isAutoClose?: boolean, width?: number, height?: number): void;
+    openPopover(event: MouseEvent, content: (h: CreateElement) => any, position?: PopperJs.Placement, isAutoClose?: boolean, width?: number, height?: number): void;
     /**
      * 销毁popper(带回填数据)
      *