title: Headers and body data going empty in http request
body: <p>This is how my service book.service.ts looks</p>
  
  <pre><code>import {Injectable} from '@angular/core';
  import {Http,Response,Headers,RequestOptions} from '@angular/http';
  import {NgForm} from '@angular/forms';
  import {Books} from './books'
  import {Observable} from 'rxjs/Observable'
  import 'rxjs/add/operator/map'; 
  import 'rxjs/add/operator/catch';
  import 'rxjs/add/operator/do';
  import 'rxjs/add/operator/toPromise';
  
  
  @Injectable()
  export class BooksService
  {
    private api = "api";
    constructor(private http:Http){}
     add_book(add_book_form,book_pdf_copy:FileList,book_pdf_sample:FileList,book_cover_image:FileList):Observable&lt;Books[]&gt;
    {
  
      let formData:FormData = new FormData();
      let pdf_copy: File = book_pdf_copy[0];
      let pdf_sample: File = book_pdf_sample[0];
      let cover_image: File = book_cover_image[0];
      for(let b in add_book_form)
      formData.append(b, add_book_form[b]);
      //console.log(formData);    
      formData.append('book_pdf_copy', pdf_copy, pdf_copy.name);
      formData.append('book_pdf_sample', pdf_sample, pdf_sample.name);
      formData.append('book_cover_image', cover_image, cover_image.name);
      let headers = new Headers(      );
  
      let options = new RequestOptions({headers:headers});
      return this.http.post(this.api+'/add_book',formData,options)
      .map(this.extractPromiseData)
      //.toPromise()
      .catch(this.handleError);
  }
  
  extractPromiseData(res:Response)
  {
      let body = res.json();
      return body;
  }
  
  // handleError(error:Response)
  // {
  //     throw(error);
  // }
  
  private handleError (error: Response | any) {
      //console.error(error.message || error);
      return Observable.throw(error.message || error);
      }
   }
  </code></pre>
  
  <p>But when I execute the above function on form submit, firefox developer console shows no headers for this request</p>
  
  <p>I searched related articles on Internet, but I didn't found any solution. I am using and angular 4 and nodejs express framework. When I try to log the req.body in nodejs it shows empty body. Please help me to solve this issue. I recently updated to angular2 same FormData was working fine before upgrading to angular 4. I know it is problem related with Formdata and header options, but don't know way to solve it. Any assistance will be helpful.</p>
  
  <p>Thanks,  </p>