Angular foreach和subscribe内部的同步网络请求

我需要的是从一个api获取数据，然后将其发送到另一个api并附加值

我尝试过使用async await，但没有成功，我认为由于嵌套类型，它不起作用

//service.ts
getRecentBackups();
{
  return this.http.get<any[]>(
    `${environment.URL}`
  );
}

getAccounts(accountId);
{
  return this.http.get(
    `${environment.URL}/${accountId}`
  );
}

//component.ts
this.abc.getRecentBackups().subscribe(data => {
  const backupData = data['activities'];
  backupData.forEach(activity => {
    const alert = new Alert();
    //Problem here need to extract response first
    let response = this.abc.getAccounts(activity['accountNum']);
    this.longRunningAlerts.push(alert);
    this.backupAlerts.push(alert);
  });
   //this should execute after above is done.
  this.totalRecentStatus = backupData.length;
  this.longRunningAlerts = [...this.longRunningAlerts];
  this.backupAlerts = [...this.backupAlerts];
}

//service.ts
getRecentBackup（）；
{
返回this.http.get

在控制台中返回Observable。
试试这个

//service.ts
getRecentBackups();
{
  return this.http.get<any[]>(
    `${environment.URL}`
  );
}

getAccounts(accountId);
{
  return this.http.get(
    `${environment.URL}/${accountId}`
  );
}

//component.ts
 this.appService.getRecentBackups().pipe(
      map(data => data['activities']),
      map(backupData => backupData.map(activity => {
        return this.appService.getAccounts(activity['accountNum']).pipe(
          map(res => ({ activity: activity, account: res }))
        )
      })),
      switchMap(apiRequest => zip(...apiRequest))
    ).subscribe(result => {
      // this.backupAlerts.push({ activity: activity, account: response });
      console.log(result);
      this.backupAlerts = [...this.backupAlerts];
      console.info('Backup Alerts', this.backupAlerts)
    })

//service.ts
getRecentBackup（）；
{
返回this.http.get


当从一个可观察值切换到下一个可观察值时，你需要使用开关映射。你能提供一些细节吗？你能看看@reactular开关映射中的一个错误吗
类型为“void”的“this”上下文不能分配给类型为“observable”的方法的“this”上下文。
@Napster你能在stackblitz和sha中创建一个例子吗re.给你，先生，请把我拉出来。@Napster更新了示例。现在你将收到这两个值