Auth.vue

<template>
  <div class="content">
    <router-view :key="$route.fullPath"/>
  </div>
</template>

<script>
  export default {
    name: 'Auth',
    router: new Router({
      mode: 'history',
      routes: [
        {
          path: 'login',
          name: 'login',
          component: () => import('./Login.vue')
        }
      ]
    })
  };
</script>

index.js

new Vue({
  router: new Router({
    mode: 'history',
    base: '',
    routes: [
      {
        path: 'auth',
        name: 'auth',
        component: () => import('./views/auth/Auth.vue'),
      }
    ],
  })
});