Two ways to define vue-route

vue-routes-case-1.js

//app.js
import VueRouter from 'vue-router';
import routes from './routes';
Vue.use(VueRouter);

const router = new VueRouter({ mode: 'history', routes: routes});
const app = new Vue({
    el: '#app',
    router //mandatory similar, because in ES6, {router} ~ {router: router}
});

//routes.js
export default [
    {
        name: 'Home',
        path: '/',
        component: require('./components/Home.vue')
    },
    {
        name: 'Example',
        path: '/example',
        component: require('./components/Example.vue')
    }
];

vue-routes-case-2.js

//app.js
import VueRouter from 'vue-router';
import router from './routes';
const app = new Vue({
    el: '#app',
    router
});


//routes.js
import Vue from 'vue'
import Router from 'vue-router'
import Hello from '@/components/Home'

Vue.use(Router)
export default new Router({
  routes: [
    {
      path: '/',
      name: 'Hello',
      component: Hello
    }
  ]
})