在angular 2中，如何等待一定的时间才能得到HTTP请求( get /POST)的响应？

import { Observable } from 'rxjs';
import { delay } from 'rxjs/operators';

import { HttpClient } from '@angular/common/http';

// ...

constructor(private http: HttpClient) {}

// ...

delayedGetRequest(): Observable<any> {
  return this.http.get('your-api-url').pipe(delay(2000)); // 延迟2秒钟
}

import { HttpClient } from '@angular/common/http';

// ...

constructor(private http: HttpClient) {}

// ...

delayedPostRequest(data: any): Observable<any> {
  return this.http.post('your-api-url', data).pipe(delay(2000)); // 延迟2秒钟
}