vue-cli 3x + element-ui 导航栏菜单高亮问题

Question

{
path: '/plan',
name: 'plan',
component: () => import('./views/plan/Plan.vue')
},
{
path: '/plandetails',
name: 'plandetails',
component: () => import('./views/plan/Plandetails.vue')
}

<el-menu
  :default-active="$route.path"
  router
  class="el-menu-vertical-demo"
  background-color="#58586E"
  text-color="#fff"
  active-text-color="#fff">
  <el-menu-item index="/plan">
    <i class="iconfont icon-jihua" style="font-size: 19px;"></i>
  </el-menu-item>
</el-menu>

    ![图片说明](https://img-ask.csdn.net/upload/201905/28/1559037119_126730.png)  点击导航栏的计划菜单进行路由跳转 ![图片说明](https://img-ask.csdn.net/upload/201905/28/1559037145_944908.png) 之后页面右侧会显示列表,![图片说明](https://img-ask.csdn.net/upload/201905/28/1559037214_390093.png), 点击某个列表会跳转到详情,![图片说明](https://img-ask.csdn.net/upload/201905/28/1559037302_313463.png),跳转到详情之后导航菜单就不高亮了![图片说明](https://img-ask.csdn.net/upload/201905/28/1559037349_19317.png),vue初学者,有点蒙,请各位大佬帮帮忙~~

Answer 1

解决了

default-active绑定了计算属性

计算属性代码