@if(currentUser?.id){
  <!-- 已登录 -->
  <h1>{{currentUser?.get("username")}}</h1>
  <button (click)="logout()">登出</button>
}
@if(!currentUser?.id){
  <!-- 未登录 -->
  <button (click)="login()">登录用户 Clym 1234</button>
}