title: Fetch API to force download file
body: <p>I'm calling an API to download excel file from the server using the fetch API but it didn't force the browser to download, below is my header response:</p>
  
  <pre><code>HTTP/1.1 200 OK Content-Length: 168667 
  Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet 
  Server: Microsoft-IIS/8.5 
  Content-Disposition: attachment; filename=test.xlsx 
  Access-Control-Allow-Origin: http://localhost:9000 
  Access-Control-Allow-Credentials: true 
  Access-Control-Request-Method: POST,GET,PUT,DELETE,OPTIONS 
  Access-Control-Allow-Headers: X-Requested-With,Accept,Content-Type,Origin 
  Persistent-Auth: true 
  X-Powered-By: ASP.NET 
  Date: Wed, 24 May 2017 20:18:04 GMT
  </code></pre>
  
  <p>Below my code that I'm using to call the API :</p>
  
  <pre><code>this.httpClient.fetch(url, {
      method: 'POST',
      body: JSON.stringify(object),
      headers: {
          'Accept': 'application/json',
          'Content-Type': 'application/json'
      }
  })
  </code></pre>