render.js

var render = function (encoding) {
  return function (page, req, res) {
    if (encoding && !req.acceptsEncodings(encoding)) {
      return false;
    }
    var content = getContent(page, encoding);
    if (content) {
      res.set('Content-Encoding', encoding);
      res.set('Content-Type', 'text/html');
      res.end(content, encoding ? 'binary' : null);
      return true;
    }
    return false;
  };
};

var renderers = [
  render('br'),
  render('gz'),
  render()
];

var renderContent = function (page, req, res) {
  return _.some(renderers, function (renderer) {
    return renderer(page, req, res);
  });
};

var showPage = function (req, res, next) {
  var page = req.params.page;
  if (!renderContent(page, req, res)) {
    return next({ status: 404 });
  }
};