在服务中声明如下:
public currentDBUserBS$: any;
constructor(private afDb: AngularFireDatabase){}
fetchUser(uid){
  this.afDb.object(`users/${uid}`).valueChanges().subscribe((dUser) => {
    if (dUser) {
      this.currentDBUserBS$ = dUser;
    }
  });
}现在尝试在模板中使用
template: `<li *ngIf="(authService.currentDBUserBS$ | async)?.role=='admin'"> Something </li>`错误堆栈:
ERROR Error: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe'
    at invalidPipeArgumentError (common.js:4219)
    at AsyncPipe._selectStrategy (common.js:5630)
    at AsyncPipe._subscribe (common.js:5612)
    at AsyncPipe.transform (common.js:5586)
    at Object.View_AppNavigatorComponent_0._co [as updateDirectives] (AppNavigatorComponent.html:40)
    at Object.debugUpdateDirectives [as updateDirectives] (core.js:14339)
    at checkAndUpdateView (core.js:13508)
    at callViewAction (core.js:13858)
    at execComponentViewsAction (core.js:13790)
    at checkAndUpdateView (core.js:13514)发布于 2017-11-28 18:37:46
你给currentDBUserBS$的是你从Firebase获取的对象,而不是Observable。如果你想这样做,你必须在你的模板中删除| async。
但是,您可以执行以下操作:
fetchUser(uid){
  this.currentDBUserBS$ = this.afDb.object(`users/${uid}`).valueChanges();
}.valueChanges()为您提供了一个观察值,并将在发出新值或修改现有值时自动更新。
https://stackoverflow.com/questions/47529286
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