How to Write for Tmp file using the Fs module in node.js

Hi i am using the tmp module to create the temp file, and i need to write that file but i am getting Error.

Here is My code

 exports.readhttpsFile = function (req, res) {
 var https = require('https'),
 tmp=require('tmp'),
  fs=require('fs');

        var tmpObj = tmp.fileSync({unsafeCleanup:false,postfix: '.xlsx'});
        var downloadedFile=tmpObj.name;
       var file = fs.createWriteStream(tmpObj.name);
            https.get('https://xxxxxxxxx/1495119759202grocer_loose_item_xlsx?alt=media', function (res3) {
                var body = '';
                res3.on('data', function (chunk) {
                    file.write(chunk);
                });
                res3.on('end', function () {
                 console.log("Read File Done");
                 res.send("Read File Done");
                });

            });
    };

But i am getting the Error like: ^

TypeError: First argument must be file descriptor
    at TypeError (native)
    at Object.fs.write (fs.js:775:18)

Can anybody help me on this

via Jeevan