vue-router使用beforeEach鉤子獲取vuex里的state值，初始頁面報錯，如何解決？router.beforeEach((to, from, next) => {  console.log(router.app.$store.state.isLogin)  if(!userinfo && to.path.indexOf('login') == -1){     return next('/login')  }else{    return next()  }});