feature: add a redirect url when not logged in (#1046)

Detail see #438

src/permission.js

@@ -52,7 +52,7 @@ router.beforeEach((to, from, next) => {
     if (whiteList.indexOf(to.path) !== -1) { // 在免登录白名单，直接进入
       next()
     } else {
-      next('/login') // 否则全部重定向到登录页
+      next(`/login?redirect=${to.path}`) // 否则全部重定向到登录页
       NProgress.done() // if current page is login will not trigger afterEach hook, so manually handle it
     }
   }