SOURCE

const Foo = { template: '<div>foo</div>'}
const Bar = { template: '<div>bar</div>'}

const routes = [
  { path: '/foo', component: Foo },
  { path: '/bar', component: Bar }
]

const router = new VueRouter({
  routes
})

const app = new Vue({
  router
}).$mount('#app')

function (var i=1; i<=5; i++) {
  (function(j){
    setTimeout(function timer(){
      console.log(j);
    },j*1000)
  })(i);
}

<script src="https://unpkg.com/vue/dist/vue.js"></script>
<script src="https://unpkg.com/vue-router/dist/vue-router.js"></script>

<div id="app">
  <h1>Hello App!</h1>
  <p>
    <router-link to="/foo">Go to Foo</router-link>
    <router-link to="/bar">Go to Bar</router-link>
  </p>
  <router-view></router-view>
</div>

.router-link-active {
  color: red;
}