permission.js

router.beforeEach(async(to, from, next) => {
    // start progress bar
    NProgress.start()

    // set page title
    document.title = getPageTitle(to.meta.title)

    // determine whether the user has logged in
    const hasToken = getToken()

    if (hasToken) {

        if (to.path === '/login') {
            // if is logged in, redirect to the home page
            next({ path: '/' })
            NProgress.done()
        } else {

            if (store.state.permission.routes.length === 0) {

                store.dispatch('GenerateRoutes').then(accessRoutes => {

                    // 根据roles权限生成可访问的路由表
                    router.addRoutes(accessRoutes) // 动态添加可访问路由表
                    next({ ...to, replace: true }) // hack方法 确保addRoutes已完成
                }).catch(err => {

                    store.dispatch('user/FedLogOut').then(() => {
                        Message.error(err)
                        next(`/login?redirect=${to.path}`)
                    })
                })
            } else {
                next()
            }
        }
    } else {
        /* has no token */
        if (whiteList.indexOf(to.path) !== -1) {

            // in the free login whitelist, go directly
            next()
        } else {

            // next(`/login?redirect=${to.path}`)
            next('/login')
            NProgress.done()
        }
    }
})

layout/components/Sidebar/index

 computed: {
            ...mapGetters([
                'sidebar'
            ]),
            routes() {
                return this.$store.state.permission.routes
                // return this.$router.options.routes
            },
            //...
}

store/modules/permission.js

import { constantRoutes } from '@/router'
import { getSystemMenu } from '@/api/user'
import Layout from '@/layout/index'

const permission = {
    state: {
        routes: [],
        addRoutes: []
    },
    mutations: {
        SET_ROUTES: (state, routes) => {
            state.addRoutes = routes
            state.routes = constantRoutes.concat(routes)
        }
    },
    actions: {
        // 生成路由
        GenerateRoutes({ commit }) {
            return new Promise(resolve => {

                // 向后端请求路由数据
                getSystemMenu().then(res => {
                    res = res ? res : []

                    const accessedRoutes = filterAsyncRouter2(res)

                    accessedRoutes.push({ path: '*', redirect: '/404', hidden: true })
                    commit('SET_ROUTES', accessedRoutes)
                    resolve(accessedRoutes)
                })
            })
        }
    }
}

// 遍历后台传来的路由字符串，转换为组件对象
function filterAsyncRouter2(asyncRouterMap) {

    function forFn(arr) {
        for (let i = 0; i < arr.length; i++) {

            if (arr[i].page_component !== '@/layout') {
                arr[i].page_component = arr[i].page_component.replace('@/views/', '')
            }

            let obj = {
                path: arr[i].page_path_key,
                name: arr[i].page_name_key,
                hidden: !arr[i].is_show_byplatform || !arr[i].is_show,
                component: arr[i].page_component === '@/layout' ? Layout : loadView(arr[i].page_component),
                meta: { title: arr[i].name, icon: arr[i].icon },
                children: arr[i].childs && arr[i].childs.length > 0 ? arr[i].childs : []
            }

            arr[i] = obj

            if (arr[i].children.length > 0) {
                forFn(arr[i].children)
            }
        }
    }

    forFn(asyncRouterMap)

    return asyncRouterMap
}

export const loadView = (view) => { // 路由懒加载
    return (resolve) => require([`@/views/${view}`], resolve)
}

export default permission