How to download file using angular from REST API?

I have hooked up following code from different blogs and SO as I couldn't find any tutorial for doing this.

What I have to do is to download a file from the REST API using angular and typescript. I do not have the access to the api (only have the url which is like "http://..." and nothing more.

Here is my typescript code:

   //Downloading File
  // may be located in any component


  let options = {
    responseType: ResponseContentType.Blob //This has compilation error. Cannot recognize ResponseContentType.Blob
  }
  // pass options to request
  this.http.get(url, options)

let type = "my/mime";
// download the file - retrieve observable
this.http.get(url, options).map((res: Body) => new Blob([res.blob()], { type: type }));

public downloadAttachment(attachment: MediaDownloadFileDto): void {
  this.myDownloadService.downloadFile(downloadUrl, mimeType).subscribe((fileBlob: Blob) => {
      fileSaver.saveAs(fileBlob, attachment.filename);
  }, (message: string) => {
      // error handling...
  });
}

// may be located in any service:
public downloadFile(url: string, type: string): Observable<Blob> {
  let options = {
      responseType: ResponseContentType.Blob
  };
  return this.http.get(url, options).map((res: Body) => new Blob([res.blob()], { type: type }));
}

Here is the HTML Button I am using:

<button class="nui-button nui-button--alt download" (click)="downloadFile(url,options)">Download Template</button>

Thanks