①設定 path 為 ‘/’

const router= new VueRouter({
  routes:[
    {path:'/',name:'home',component:Home},             //頁面第一顯示的元件
    {path:'/menu',name:'menu',component:Menu},
    {path:'*',redirect:'/'}
  ],
  mode:"history"
});

②設定  redirect  的值（適用於 二級路由）
 

const router= new VueRouter({
  routes:[
    {path:'/',name:'home',component:Home},
    {path:'/about',name:'about',component:About,redirect:{name:'contactLink'},children:[   //二級路由
        {path:'/about/contact',name:'contactLink',component:Contact},
        {path:'/history',name:'historyLink',component:History},
      ]},
    {path:'*',redirect:'/'}
  ],
  mode:"history"
});