Angular 6如何存储部分API响应以便在新的HttpGet语句中使用？

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { BehaviorSubject } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class DataService {
  private dataSubject = new BehaviorSubject<any>(null);
  public data$ = this.dataSubject.asObservable();

  constructor(private http: HttpClient) { }

  fetchData() {
    this.http.get('your-api-url').subscribe(response => {
      this.dataSubject.next(response);
    });
  }
}

import { Component, OnInit } from '@angular/core';
import { DataService } from 'path-to-data-service';

@Component({
  selector: 'app-your-component',
  templateUrl: './your-component.component.html',
  styleUrls: ['./your-component.component.css']
})
export class YourComponent implements OnInit {
  data: any;

  constructor(private dataService: DataService) { }

  ngOnInit() {
    this.dataService.data$.subscribe(response => {
      this.data = response;
    });
  }

  fetchData() {
    this.dataService.fetchData();
  }
}