ngf-select taking almost 10 seconds to initiate $file

Question

In angularjs, I am using it like

   <input type="file" id="fileInput" ngf-select="uploadDocFile($file)" accept=".pdf,.png"  />

$file takes too much time to initiate in uploadDocFile function (almost 10 seconds) if I select and upload any file before this time, my file is uploaded on the URL multiple times