// router.js
router.beforeEach((to, from, next) => {
 if (!to.meta.user) {
  // todo 请求接口获取数据
  loadUserData().then(user => {
   // 存放源信息
   to.meta.user = user
   // 存在 vuex 中
   store.state.user = user
   if(user){
    next()
   }else{
    next({
     path: '/'
    })
   }
  })
 } else {
  next()
 }
})

// api.js
import axios from 'axios'

// 封装ajax 的 fetch
export let fetch = (method, url, data, forceLogin = true) => {
 return new Promise((resolve, reject) => {
  axios({
   ...data,
   method: method,
   url: url
  }).then(response => {
   resolve(response.data)
  }).catch(err => {
   reject(err)
  })
 })
}

// 获取用户信息
export let loadUserData = () => {
 return new Promise((resolve, reject) => {
  let user = null
  let cacheKey = 'authUserJsonStr'
  let authUserJsonStr = sessionStorage.getItem(cacheKey)
  if (authUserJsonStr) {
   user = JSON.parse(sessionStorage.getItem(cacheKey))
   resolve(user)
  } else {
   fetch('GET', '/api/auth_info/', {}, false).then((data) => {
    user = data
    sessionStorage.setItem(cacheKey, JSON.stringify(user))
    resolve(user)
   }).catch(() => {
    resolve(null)
   })
  }
 })
}