old_contents: var express = require('express');
  var compression = require('compression');
  var bodyParser = require('body-parser');
  var cors = require('cors');
  var path = require('path');
  var fs = require('fs');
  
  var app = express();
  var api = express.Router();
  
  // config
  var static_path = path.join(__dirname, '/../build');
  var data_dir    = process.env.MONOD_DATA_DIR || path.join(__dirname, '/../data');
  
  app.set('port', process.env.PORT || 3000);
  
  // middlewares
  app.use(compression());
  app.use(express.static(static_path));
  app.use(bodyParser.json());
  app.use(cors());
  app.use(api);
  
  const isValidId = (uuid) => {
    return /[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12}/.test(uuid);
  };
  
  // Match UUIDs
  app.get('/[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12}', (req, res) => {
    res.sendFile('index.html', {
      root: static_path
    });
  });
  
  // API
  api.get('/documents/:uuid', (req, res) => {
    var uuid = req.params.uuid;
  
    // request validation
    if (!isValidId(uuid)) {
      return res.status(400).json();
    }
  
    fs.readFile(path.join(data_dir, uuid), (err, data) => {
      if (err) {
        console.log(err);
        return res.status(404).json();
      }
  
      return res.json(JSON.parse(data));
    });
  });
  
  api.put('/documents/:uuid', (req, res) => {
    const uuid = req.params.uuid;
  
    // request validation
    if (!isValidId(uuid) || !req.body.content) {
      return res.status(400).json();
    }
  
    const filename = path.join(data_dir, uuid);
  
    fs.readFile(filename, (err, data) => {
      const isNew = err ? true : false;
      const document = isNew ? {} : JSON.parse(data);
  
      document.uuid          = uuid;
      document.content       = req.body.content;
      document.last_modified = Date.now();
  
      fs.writeFile(filename, JSON.stringify(document), (err) => {
        if (err) {
          return res.status(500).json();
        }
  
        return res.status(isNew ? 201 : 200).json(document);
      });
    });
  });
  
  // Listen only when doing: `node app/server.js`
  if (require.main === module) {
    app.listen(app.get('port'), () => {
      console.log('Running at localhost:' + app.get('port'));
    });
  }
  
  module.exports = app;
  
new_contents: var express = require('express');
  var compression = require('compression');
  var bodyParser = require('body-parser');
  var cors = require('cors');
  var path = require('path');
  var fs = require('fs');
  
  var app = express();
  var api = express.Router();
  
  // config
  var static_path = path.join(__dirname, '/../build');
  var data_dir    = process.env.MONOD_DATA_DIR || path.join(__dirname, '/../data');
  
  app.set('port', process.env.PORT || 3000);
  app.set('etag', false);
  
  // middlewares
  app.use(compression());
  app.use(express.static(static_path));
  app.use(bodyParser.json());
  app.use(api);
  
  // this is required to be able to run another server in dev
  if ('production' !== process.env.NODE_ENV) {
    app.use(cors());
  }
  
  const isValidId = (uuid) => {
    return /[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12}/.test(uuid);
  };
  
  // Match UUIDs
  app.get('/[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12}', (req, res) => {
    res.sendFile('index.html', {
      root: static_path
    });
  });
  
  // API
  api.get('/documents/:uuid', (req, res) => {
    var uuid = req.params.uuid;
  
    // request validation
    if (!isValidId(uuid)) {
      return res.status(400).json();
    }
  
    fs.readFile(path.join(data_dir, uuid), (err, data) => {
      if (err) {
        console.log(err);
        return res.status(404).json();
      }
  
      return res.json(JSON.parse(data));
    });
  });
  
  api.put('/documents/:uuid', (req, res) => {
    const uuid = req.params.uuid;
  
    // request validation
    if (!isValidId(uuid) || !req.body.content) {
      return res.status(400).json();
    }
  
    const filename = path.join(data_dir, uuid);
  
    fs.readFile(filename, (err, data) => {
      const isNew = err ? true : false;
      const document = isNew ? {} : JSON.parse(data);
  
      document.uuid          = uuid;
      document.content       = req.body.content;
      document.last_modified = Date.now();
  
      fs.writeFile(filename, JSON.stringify(document), (err) => {
        if (err) {
          return res.status(500).json();
        }
  
        return res.status(isNew ? 201 : 200).json(document);
      });
    });
  });
  
  // Listen only when doing: `node app/server.js`
  if (require.main === module) {
    app.listen(app.get('port'), () => {
      console.log('Running at localhost:' + app.get('port'));
    });
  }
  
  module.exports = app;
  
subject: Tweak node server