修改获取openId的bug

src/pages/buy/index.vue

@@ -83,7 +83,9 @@ export default {
       return this.query.shop_id || '6800681447305773056'
     },
     openId () {
-      return window.localStorage.getItem('openId') // 'oF3a-t9pFpmL2gWuTmtWs5HlDGkU'
+      let openId = window.localStorage.getItem('openId')
+      if (openId === 'undefined' || openId === 'null') openId = ''
+      return openId // 'oF3a-t9pFpmL2gWuTmtWs5HlDGkU'
     }
   },
   beforeMount() {