const router = new VueRouter({ ... })

router.beforeEach((to, from, next) => {
 // ...
})

import Vue from 'vue'
import Router from 'vue-router'
import Login from '@/pages/login/Login'
import Index from '../pages/index/Index'
import Library from '../pages/library/Library'
import Design from '../pages/design/Design'
import Administration from '../pages/administration/Administration'
import Production from '../pages/production/Production'

import Global from '../common/global/Global'

Vue.use(Router)

const router = new Router({
 routes: [
 {
  path: '/',
  name: 'login',
  component: Login
 }, {
  path: '/index',
  name: 'index',
  component: Index
 }, {
  path: '/library',
  name: 'library',
  component: Library
 }, {
  path: '/design',
  name: 'design',
  component: Design
 }, {
  path: '/administration',
  name: 'administration',
  component: Administration
 }, {
  path: '/production',
  name: 'production',
  component: Production
 }
 ]
})

router.beforeEach ((to,from,next) => {
 //将所有需要登陆才显示的页面的路由都放进一个数组
 const nextRoute = ['index', 'library', 'design', 'administration', 'production'];
 //获取登陆状态
 let isLogin = Global.isLogin
 
 if(to.name === 'login') { //如果是登录页，则跳过验证
 next() //必不可少
 return //以下的代码不执行
 }
 if(nextRoute.indexOf(to.name) >= 0) { //判断该页面是否需要登陆
 if(!isLogin) { //判断登陆状态
  next({ name : 'login'}) //如果未登录，则跳转到登录页
 } else {
  next() //如果已经登陆，那就可以跳转
 }
 } else { //其他的无需登陆的页面不做验证
  next()
 }
 
})

export default router

 if(isLogin) {
 next()
 } else {
 next({ name: 'login')}
 }

 if(to.name === 'login') { 
 next() 
 return 
 }