将事件传递给指令并订阅它

我有一个输出为eventEmitter的指令。 我想在已发出事件返回订阅的订阅完成后做一些事情。

(例如,当example.component的save()完成时,我想做console.log(“test”)。-我知道我可以在示例中这样做。组件的save方法,但我正在做一些常规的事情,所以我需要在指令中使用它)。

import { Directive, OnInit, HostListener, Output, EventEmitter } from '@angular/core';

@Directive({
  selector: '[appSingleActiveButton]'
})
export class SingleActiveButtonDirective {
  @Output() appSingleActiveButton: EventEmitter<any> = new EventEmitter();

  constructor() {}

  @HostListener('click', ['$event'])
  private onClick(e: any): void {
    this.appSingleActiveButton.next(e);
    //determine somehow that the referred function's subscription is completed and do something
    // for example what I tried is: this.appSingleActiveButton.subscribe(() => console.log('do some other stuff'))
  }
}

我有一个组件,它有一个带有该指令的元素,并传递一个返回订阅的函数。

示例.component.ts:

import { Component } from '@angular/core';
import { Subscription } from 'rxjs/Rx';
import { Http } from '@angular/http';

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.scss'],
})
export class ExampleComponent {

  constructor(private http: Http) {}

  public save(index: number): Subscription {
    const requestUrl = 'http://example.com';
    return this.http
    .get(requestUrl)
    .map((response) => response.json()).subscribe(() => console.log(`doing some stuff ${index}`));
  }
}

示例.component.html

<div *ngFor="let btn of btns; let i = index">
    <div (appSingleActiveButton)="save(i)">test directive</div>
</div>

编辑 : 问题如下:

我怎样才能确定 save() 在我实际调用它的指令内完成(成功或错误) this.appSingleActiveButton.next(e);