这样写全局守卫跳转登陆：

router.beforeEach((to, from, next) => {
  // to and from are both route objects
  let isLogin = false
  if (isLogin) {
    next()
  } else {
    next({
      path: '/login',
      query: {redirect: to.fullPath}
    })
  }
})

报错 [vue-router] uncaught error during route navigation:

<failed to convert exception to string>

陷入了死循环，采用下面的写法就可以正常解析了，isLogin可以根据后台传递的变量存入Vuex中来管理

router.beforeEach((to, from, next) => {
  // to and from are both route objects
  let isLogin = false
  let path = to.path
  if (path === '/login') {
    next()
    return
  }
  if (isLogin) {
    next()
  } else {
    next({
      path: '/login',
      query: to.fullPath
    })
  }
})