如何取消预览Angular 2中服务中相同类型的不完整HTTP请求？

import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import { Observable, Subject } from 'rxjs';
import { catchError, takeUntil } from 'rxjs/operators';

private cancelRequest$ = new Subject<void>();

constructor(private http: HttpClient) { }

public getData(): Observable<any> {
  return this.http.get<any>('api/data')
    .pipe(
      takeUntil(this.cancelRequest$),
      catchError((error: HttpErrorResponse) => {
        // 处理错误
        return throwError(error);
      })
    );
}

public cancelRequest(): void {
  this.cancelRequest$.next();
}