修改数组对象的Observable的内容

   getFiles(): Observable<File[]> {
    const makeFiles = map((response: FileResponse[]): File[] => {
      return response.map((fileResponse: FileResponse): File => {
        return File.fromResponse(fileResponse);
      });
    });

    return this.httpService.get('/profile/files').pipe(
      makeFiles,
      shareReplay(),
    );
  }

  getFileUri(filename: string): Observable<SafeUrl> {
    return this.httpService.get(`/profile/file/uri/${filename}`).pipe(
      mergeMap((uri: string) => this.httpService.get(uri, {}, { useUrlAsItIs: true, responseType: 'arraybuffer' })),
      map((fileBuffer: any) => {
        const unsafeUrl = URL.createObjectURL(new Blob([fileBuffer], {type: 'application/binary'}));
        const safeUrl = this.sanitizer.bypassSecurityTrustUrl(unsafeUrl);

        return safeUrl;
      })
    );
  }