How can I handle custom file name pdf preview with new tab and can download with specific file name?

At first, I want to open pdf as preview in new tab and then I want to download if I click download icon from that preview with specific name.

I want to change from

blob:http://localhost:4200/22102378-755e-45ba-8c3d-d95b09013fa6

**to **

blob:http://localhost:4200/fileName.pdf

My current code is

  previewPDF(url): any {
    return this.http.get(url, { responseType: 'blob' }).toPromise().then(
      (res) => {
        return new Blob([res], { type: 'application/pdf' });
      });
  }


  previewInfoPDF() {
    const promises = this.previewInfo.map(async info=> {
      return this.apiSvc.previewPDF(info.url);
    });

    Promise.all(promises).then(results => {
      results.map(res => {
        const fileURL = URL.createObjectURL(res);
        window.open(fileURL, '_blank');
      });
    });
  }

To open in new tab as preview is correct with my code. My requirement is to download with specific file Name when i click download button from that url.