Simple express server that admits HTML5 routing

server.js

const express = require("express");
const compression = require("compression");
const url = require("url");
const path = require("path");

const PORT = 4200;

// resolve pathname whether it is a static file or rewrite it to index.html (default start page for all pages)
const getFilename = (req) => {
  const pathname = url.parse(req.url).pathname;

  // serve static files
  if (pathname.match(/.*(js|css|scss|jpg|jpeg|gif|ico|png|bmp|csv|doc|pdf|ttf|eot|eps|swf|woff|woff2|svg)$/)) {
    return pathname;
  }

  // if not static, rewrite
  return 'index.html';
};

const app = express();

app.use(compression());

app.get('*', function (req, res) {
  const filename = getFilename(req);
  res.sendFile(path.join(__dirname, "dist/frontend", filename));
});

app.listen(PORT, function () {
  console.log("Listening on " + PORT);
});