vue.js运行时界面空白，报_vueRouter2.defaultisnotaconstructor？

at Object. (router.js:24)

at __webpack_require__ (bootstrap c0f0e95…:52)

at Object. (entry.js:2)

at __webpack_require__ (bootstrap c0f0e95…:52)

at webpackJsonpCallback (bootstrap c0f0e95…:23)

at bundle.js:1

import Vue from 'vue';

import App from '../App.vue';

import VueRouter from 'vue-router';

import VueResource from 'vue-resource';



Vue.use(VueRouter);

Vue.use(VueResource);



import GDMap from './views/gdmap.vue'

import Admins from './views/admins.vue'

import Drivers from './views/drivers.vue'

import Vehicles from './views/vehicles.vue'

import Stations from './views/stationsTest.vue'

import Routes from './views/routes.vue'

import Frequencies from './views/frequencies.vue'

import Login from './views/login.vue'

import OrderBuses from './views/orderBuses.vue'

import OrderTravels from './views/orderTravels.vue'

import OrderCharters from './views/orderCharters.vue'

import Cities from './views/cities.vue'

import Permissions from './views/permissions.vue'

import Common from './Common.vue'



export default new VueRouter ({

  mode: 'history',

  scrollBehavior: () => ({ y: 0 }),

  routes: [

    { path: '/l/:page', component: Login},

    { path: '/k/common', component: Common, children: [

        { path: '/m/:page', component: GDMap },

        { path: '/c/:page/:id(\\d+)?', component: Cities },

        { path: '/p/:page/:id(\\d+)?', component: Permissions },

        { path: '/a/:page/:id(\\d+)?', component: Admins },

        { path: '/d/:page/:id(\\d+)?', component: Drivers },

        { path: '/v/:page/:id(\\d+)?', component: Vehicles },

        { path: '/s/:page/:id(\\d+)?', component: Stations },

        { path: '/r/:page/:id(\\d+)?', component: Routes },

        { path: '/f/:page/:id(\\d+)?', component: Frequencies },

        { path: '/b/:page/:id(\\d+)?', component: OrderBuses },

        { path: '/t/:page/:id(\\d+)?', component: OrderTravels },

        { path: '/o/:page/:id(\\d+)?', component: OrderCharters },

        { path: '*', redirect: 'm/map'  }

    ]},

    { path: '*', redirect: 'l/login' }

  ]

})