如何在 function 返回之前等待代码/订阅完成

Question

我需要等待我的 function 中的 2 订阅完成，然后它才会返回 'this.getRows('employee')' 的值。 最好的方法是什么？ 也许 rxjs 会有所帮助，但我对此并不满意。 先感谢您

getEmployeesTable(): Table {
    this.backendService.getEmployeeSummaryTable().subscribe((employees) => {
      this.emloyeeSummary = employees;
    });
    this.backendService.getEmployeesTable().subscribe((employees) => {
      this.emloyees = employees;
    });
    setTimeout(() => (table = this.getRows('employee')), 1000); // this does not help

    return this.getRows('employee'); // this should only return after the 2 functions above 
                                     //finished 
  }

Answer 1

forkJoin会等待两个异步操作完成

getEmployeesTable():Observable<Table>{
  
  return forkJoin({
    emloyeeSummary: this.backendService.getEmployeeSummaryTable(),
    employees: this.backendService.getEmployeesTable()
  }).pipe(
    tap((res) => {
     this.emloyeeSummary = res.emloyeeSummary;
     this.emloyees = res.employees;
    }),
    map(() => this.getRows('employee'))
  );
}