title: fs.writeFile not overwriting file
body: <p>I am using node-crontab to run the script.  fs.writeFile overwrite first time the loop runs but after that is appending data.  I have tried deleting the file before writing but is doing the same, deletes it the first time but in the subsequent runs start to append.  What should I do?</p>
  
  <p>This is the script: I ommited some environment variables...</p>
  
  <pre><code>var jobId = crontab.scheduleJob('* * * * *', function() {
  //Gettting  system date and adding leading zeros when are single digits.  I need this to build the get request with date filters.
  
      var d = new Date();
      var nday = d.getDate();
      var nmonth = d.getMonth();
      var nhour = d.getHours();
      var nmin = d.getMinutes();
  
      var nfullyear = d.getFullYear();
      if (nday &lt; 10) {
          nday = '0' + nday;
      };
      var nmin = nmin - 1;
      if (nmin &lt; 10) {
          nmin = '0' + nmin;
      };
      if (nhour &lt; 10) {
          nhour = '0' + nhour;
      };
  
      var nmonth = nmonth + 1;
      if (nmonth &lt; 10) {
          nmonth = '0' + nmonth;
      };
  
      var options = {
          url: 'https://credentials@api.comettracker.com/v1/gpsdata' + '?fromdate=' + nfullyear + '-' + nmonth + '-' + nday + 'T' + nhour + '%3a' + nmin + '%3a' + '00',
          method: 'GET',
          rejectUnauthorized: !debug
      };
  
  
  // HTTP get request
        request(options, function(error, response, body) {
          if (error) throw new Error(error);
          var result = JSON.parse(body)['gps-recs'];
  
          console.log(result.length);
  
          //create .csv file 
          buildCSV(result);
  
      });
  });
  
  function buildCSV(result) {
  
  
      //adding headers
      csvFile = csvFile.concat('UserNumber' + ',' + 'UserTimeTag' + ',' + 'Latitude' + ',' + 'Longitude' + ',' + 'SpeedMph' + ',' + 'Heading' + ',' + 'Status' + '\r\n');
      // loop runs result.length times
      for (var i = 0; i &lt; result.length; i++) {
          csvFile = csvFile.concat(result[i].UserInfo.UserNumber + ',' + result[i].UserTimeTag + ',' + result[i].Latitude + ',' + result[i].Longitude + ',' + result[i].SpeedMph + ',' + result[i].Heading + ',' + result[i].Status + '\r\n');
  
      };
      //delete file.csv first
      console.log('before unlink: ');
      fs.unlink('file.csv', function(err){
          if (err) throw err; 
          else {
              console.log('file deleted'); 
              console.log(csvFile);
              fs.writeFile('file.csv', csvFile, function(err) {
  
              if (err) throw err;
              console.log('file saved');
  
              });
          };
  
      });
  };
  </code></pre>