"Cannot read properties of undefined (reading 'matched')"

Question

vue cli要根据路由生成菜单，于是将new Router赋值给一个常量，再将常量导出，但是会报错

页面也渲染不出来。
具体代码如下

更改前代码↓

const routes = [
  {
    name: "layout",
    path: '/',
    component: () => import('@/layout'),
    redirect: '/home',
    children: [
      {
        path: '/home',
        name: 'home',
        component: home,
        meta: { title: '首页' }
      },
    ]
  },
]
export default new Router({({
  routes: routes
})

更改后代码↓

const routes = [
  {
    name: "layout",
    path: '/',
    component: () => import('@/layout'),
    redirect: '/home',
    children: [
      {
        path: '/home',
        name: 'home',
        component: home,
        meta: { title: '首页' }
      },
    ]
  },
]
const router = new Router({
  routes: routes
})

请问这是为什么？。。