<!-- keepAlList是用来动态判断组件是否需要keep-alive,建议保存到vuex中作为全局变量，至于下方的css动画，看官可以按照喜好自由修改-->
<transition :name="transNa">
 <keep-alive :include="keepAlList">
 <router-view class="child-view"></router-view>
 </keep-alive>
</transition>
<style scoped>
.child-view {
 position: absolute;
 width: 100%;
 height: 100%;
 transition: all .5s ease;
 -webkit-transition: all .5s ease;
 -moz-transition: all .5s ease;
}
.rightin-enter,
.leftin-leave-active {
 opacity: 0;
 transform: translate3d(50% 0, 0);
 -webkit-transform: translate3d(50%, 0, 0);
 -moz-transform: translate3d(50%, 0, 0);
}
.leftin-enter,
.rightin-leave-active {
 opacity: 0;
 transform: translate3d(-50% 0, 0);
 -webkit-transform: translate3d(-50%, 0, 0);
 -moz-transform: translate3d(-50%, 0, 0);
}
</style>

//进入路由之前设置拦截器
let noLoginList = ["login", "register", "forget", "home", "classify", "goodsDetial"];
router.routeInfo.beforeEach((to, from, next) => {
 let user = sessionStorage.getItem('user');
 //如果要去登录页面
 if (noLoginList.indexOf(to.name) >= 0) {
  if (!user || user == '') {
   //未登录的状态通行
   next();
   return;
  } else {
   if (["login", "register", "forget"].indexOf(to.name) >= 0) {
    //已登录的状态去首页
    next({
     name: 'home'
    });
    return;
   } else {
    //已登录的状态去首页
    next();
    return;
   }
  }
 } else {
  //去登录页面以外的页面(以下是本文关键代码)
  if (user && user != '') {
   //判断是否为需要缓存组件,如果是添加组件名到数组
   if (to.meta.keepAlive) {
    const toName = to.name;
    let keepLi = store.getters.getKeepAlList;
    keepLi.indexOf(toName) < 0 ? keepLi.push(toName) : '';
    store.commit('SET_KEEPALLIST', keepLi);
   }
   //根据路径名深度设置转场动画类型
   store.commit('SET_TRANSNA', (to.path.split('/').length < from.path.split('/').length ? 'leftin' : 'rightin'));
   next();
  } else {
   let toWhere = router.nameList.indexOf(to.name) >= 0 ? to : {name: 'home'};
   next({
    name: 'login',
    params: {
     jumpTo: {
      name: toWhere.name,
      params: toWhere.params,
      query: toWhere.query,
     },
    }
   });
  }
 }
});