`retryWhen`过期后如何返回值？ （对于 `canActivate` 守卫）

Question

当我重新加载我的页面时，它总是转到空白页面而不是同一页面。这背后的原因是一旦用户刷新页面就会调用 canActivate 方法，该方法正在检查用户的权限，并且无法立即获取用户数据。用户数据会在几秒钟后出现。

我发现我可以在订阅中使用retryWhen，所以调用会重试3次，如果没有完成，我可以调用navigateToNoAccessArea()函数。

功能如下：

canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot):         
     Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree 
  {
    return this.getUserData(route);
   
  }

  private getUserData(route: ActivatedRouteSnapshot): Observable<boolean> {
    return this.userService.getUserData()
      .pipe(
        map(userData => {
          // If userData is empty, it returns an error (and catched in retryWhen)
          if(userData === null) throw new Error('User Data not initialized');
          return userData;
        }),
        // when no data is present, it retries the subscription (up to 3 times)
        retryWhen(err => err.pipe(delay(1000), take(3),
          finalize(()=> {
          //   this is called after it fails 3 times
          //   return does not work
            this.navigateToNoAccessArea();
            return false;
          })
        )),
        map(userData=> {
          // this map is called when data is got (if the retry fails 3 times it is skipped)
          // ***Some data manipulation is done here and true or false is returned ***
        }),
      )
  }

如果重试失败 3 次，我应该以某种方式返回 false（因此 canActivate() 不会与 EmptyErrorImpl {message: 'no elements in sequence', name: 'EmptyError'} 出错。重定向到无访问区域的工作正常。

Answer 1

试试这个：

retryWhen(err =>{ 
let flag = true;
err.pipe(delay(1000), take(3),
          finalize(()=> {
          //   this is called after it fails 3 times
          //   return does not work
            this.navigateToNoAccessArea();
            flag=false;
          });
return flag;
        )),