Node js undefined printed using fs.appendFile

Question

I have just started out learning Node js. I can't understand why in output.txt I am seeing "2020 Septemberundefined undefined" in output.txt when I call:

http://localhost/?month=September&year=2020

I am expecting to see just "2020 September" in output.txt.

var http = require('http');
var url = require('url');
var fs = require('fs');

//create a server object:
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/html'});
  var q = url.parse(req.url, true).query;
  var txt = q.year + " " + q.month;
  fs.appendFile('output.txt', txt, function (err) {
        // nothing
  });
  res.end(); //end the respons
}).listen(8080); //the server object listens on port 8080

Dan D. · Accepted Answer · 2019-09-08 12:27:17Z

1

The favorite icon. Add console.log(req.url). You will see that the browser makes two requests.

answered Sep 8, 2019 at 12:27

Dan D.

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Comments

Rupesh Rajhans · Accepted Answer · 2019-09-08 13:37:34Z

Browser is sending requests for http://localhost:8080/favicon.ico, behind the scenes.

So whenever you hit http://localhost:8080/?month=September&year=2020, node write "2020 September" to output.txt file, meanwhile browser hit favicon.ico request then node write again "undefined undefined" in output.txt file.

if you want to skip favicon.ico request,

var http = require('http');
var url = require('url');
var fs = require('fs');

//create a server object:
http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/html'});
    if (req.url != '/favicon.ico') {
      var q = url.parse(req.url, true).query;
      var txt = q.year + " " + q.month;
      fs.appendFile('output.txt', txt, function (err) {
            // nothing
      });
    }
  res.end(); //end the respons
}).listen(8080);

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