Empty file written - demo code

emptyfile.js

var fs = require('fs');

var file_tree = ['test1.txt', 'test2.txt'];
var data = ['d1', 'd2'];

for(i in file_tree) {

  fp = fs.createWriteStream(file_tree[i]);

  for(i in data) {
    fp.write(data[i]+'\n', function (err) { if(err) throw err;});
  }

}