upload.ts

const req = new HttpRequest('POST', '/upload/article', file, {
  reportProgress: true,
});

http.request(req).subscribe(event => {
  // you get now access to the raw event stream.
  if (event.type === HttpEventType.UploadProgress) {
    // This is an upload progress event. Compute and show the % done:
    const percentDone = Math.round(100 * event.loaded / event.total);
    console.log(`File is ${percentDone}% uploaded.`);
  } else if (event instanceof HttpResponse) {
    console.log('File is completely uploaded!');
  }
});