How to get file object from file_attachment?

I followed this code and so far I could get the file attachment object. But I can't seem to get the file. I need the file object to upload to IPFS via Javascript.

(function($){

    $.extend( wp.Uploader.prototype, {
        success : function( file_attachment ){
            console.log( file_attachment );
        }
    });
})(jQuery);

Or, how can I get the JS file object after a file is uploaded?