save.js

var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var fs = require('fs');
var beautify_html = require('js-beautify').html;


app.use(bodyParser.json());
app.use(bodyParser.urlencoded());
app.use(bodyParser.urlencoded({ extended: true }));

app.post('/file', function(req, res){

  var fileContent = beautify_html(req.body.fileContent);
  
  fs.writeFile(__dirname + '/www/' + req.body.fileName , fileContent, function(err) {
      if(err) {
          return console.log(err);
      }

      res.send('http://localhost:3000/www/' + req.body.fileName);
  });
});

app.use('/www', express.static(__dirname + '/www'));

var server = app.listen(3000, function () {
  var host = server.address().address;
  var port = server.address().port;

  console.log('App listening at http://%s:%s', host, port);
});