可完全參考 vue-element-admin：https://github.com/PanJiaChen/vue-element-admin 中的實現。

但是有幾個非常需要注意的地方，我第一次參照著實現了以後，過了一段時間做另一個專案居然又花了不少時間，遂做個詳細記錄。

需要改動的地方：

1、src/router/index.js

export const asyncRoutes = [
{
    path: '/permission',
    component: Layout,
    redirect: '/permission/page',
    alwaysShow: true, // will always show the root menu
    name: 'Permission',
    meta: {
      title: 'Permission',
      icon: 'lock',
      roles: ['admin', 'editor'] // you can set roles in root nav
    },
    children: [
      {
        path: 'page',
        component: () => import('@/views/permission/page'),
        name: 'PagePermission',
        meta: {
          title: 'Page Permission',
          roles: ['admin'] // or you can only set roles in sub nav
        }
      }
    ]
  },
  // 404 page must be placed at the end !!!
  { path: '*', redirect: '/404', hidden: true }
]

2、src/permission.js

import router from './router'
import store from './store'
import { Message } from 'element-ui'
import NProgress from 'nprogress' // progress bar
import 'nprogress/nprogress.css' // progress bar style
import { getToken } from '@/utils/auth' // get token from cookie
import getPageTitle from '@/utils/get-page-title'

NProgress.configure({ showSpinner: false }) // NProgress Configuration

const whiteList = ['/login', '/auth-redirect'] // no redirect whitelist

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() // hack: https://github.com/PanJiaChen/vue-element-admin/pull/2939
    } else {
      // determine whether the user has obtained his permission roles through getInfo
      const hasRoles = store.getters.roles && store.getters.roles.length > 0
      if (hasRoles) {
        next()
      } else {
        try {
          // get user info
          // note: roles must be a object array! such as: ['admin'] or ,['developer','editor']
          const { roles } = await store.dispatch('user/getInfo')

          // generate accessible routes map based on roles
          const accessRoutes = await store.dispatch('permission/generateRoutes', roles)

          // dynamically add accessible routes
          router.addRoutes(accessRoutes)

          // hack method to ensure that addRoutes is complete
          // set the replace: true, so the navigation will not leave a history record
          next({ ...to, replace: true })
        } catch (error) {
          // remove token and go to login page to re-login
          await store.dispatch('user/resetToken')
          Message.error(error || 'Has Error')
          next(`/login?redirect=${to.path}`)
          NProgress.done()
        }
      }
    }
  } else {
    /* has no token*/

    if (whiteList.indexOf(to.path) !== -1) {
      // in the free login whitelist, go directly
      next()
    } else {
      // other pages that do not have permission to access are redirected to the login page.
      next(`/login?redirect=${to.path}`)
      NProgress.done()
    }
  }
})

router.afterEach(() => {
  // finish progress bar
  NProgress.done()
})

3、src/store/modules/permission.js

import { asyncRoutes, constantRoutes } from '@/router'

/**
 * Use meta.role to determine if the current user has permission
 * @param roles
 * @param route
 */
function hasPermission(roles, route) {
  if (route.meta && route.meta.roles) {
    return roles.some(role => route.meta.roles.includes(role))
  } else {
    return true
  }
}

/**
 * Filter asynchronous routing tables by recursion
 * @param routes asyncRoutes
 * @param roles
 */
export function filterAsyncRoutes(routes, roles) {
  const res = []

  routes.forEach(route => {
    const tmp = { ...route }
    if (hasPermission(roles, tmp)) {
      if (tmp.children) {
        tmp.children = filterAsyncRoutes(tmp.children, roles)
      }
      res.push(tmp)
    }
  })

  return res
}

const state = {
  routes: [],
  addRoutes: []
}

const mutations = {
  SET_ROUTES: (state, routes) => {
    state.addRoutes = routes
    state.routes = constantRoutes.concat(routes)
  }
}

const actions = {
  generateRoutes({ commit }, roles) {
    return new Promise(resolve => {
      let accessedRoutes
      if (roles.includes('admin')) {
        accessedRoutes = asyncRoutes || []
      } else {
        accessedRoutes = filterAsyncRoutes(asyncRoutes, roles)
      }
      commit('SET_ROUTES', accessedRoutes)
      resolve(accessedRoutes)
    })
  }
}

export default {
  namespaced: true,
  state,
  mutations,
  actions
}

4、src/store/getters.js

5、src/layout/components/Sidebar/index.vue

需要把 routes 改為 permission_routes

<template>
  <div :class="{'has-logo':showLogo}">
    <logo v-if="showLogo" :collapse="isCollapse" />
    <el-scrollbar wrap-class="scrollbar-wrapper">
      <el-menu
        :default-active="activeMenu"
        :collapse="isCollapse"
        :background-color="variables.menuBg"
        :text-color="variables.menuText"
        :unique-opened="false"
        :active-text-color="variables.menuActiveText"
        :collapse-transition="false"
        mode="vertical"
      >
        <sidebar-item v-for="route in permission_routes" :key="route.path" :item="route" :base-path="route.path" />
      </el-menu>
    </el-scrollbar>
  </div>
</template>

<script>
import { mapGetters } from 'vuex'
import Logo from './Logo'
import SidebarItem from './SidebarItem'
import variables from '@/styles/variables.scss'

export default {
  components: { SidebarItem, Logo },
  computed: {
    ...mapGetters([
      'permission_routes',
      'sidebar'
    ]),
    activeMenu() {
      const route = this.$route
      const { meta, path } = route
      // if set path, the sidebar will highlight the path you set
      if (meta.activeMenu) {
        return meta.activeMenu
      }
      return path
    },
    showLogo() {
      return this.$store.state.settings.sidebarLogo
    },
    variables() {
      return variables
    },
    isCollapse() {
      return !this.sidebar.opened
    }
  }
}
</script>