vue 报错 Failed to mount component: template or render function not defined.

后管当中的侧边栏的跳转路径都对
  但是点击跳转的时候就报错,

[Vue warn]: Failed to mount component: template or render function not defined.

导致点击没有任何反应在对应的页面

The reason is that when you import the file, you refer to it like this,

and then we add .default