path-to-regexp example

server.js

var express = require('express');
var pathToRegexp = require('path-to-regexp');

var entriesIndex = function() {
  return 'entry list html';
};

var entriesShow = function(params) {
  return 'entry item html : ' + params[0];
};

var notFound = function() {
  return 'not found';
};

var getRoutes = function() {
  return [
    ['/entries', entriesIndex],
    ['/entries/:id', entriesShow],
    ['*', notFound]
  ].map(function(route) {
    return {
      re: pathToRegexp(route[0]),
      handler: route[1]
    };
  });
}

var render = function(routes, path) {
  for (var i = 0; i < routes.length; i++) {
    var route = routes[i];
    var match = route.re.exec(path);
    if (match) return route.handler(match.slice(1));
  }
  return null;
};

var main = function() {
  var routes = getRoutes();
  var app = express();
  app.get('*', function(req, res) {
    res.send(render(routes, req.path));
  });
  app.listen(3000);
};

main();

$ npm i express path-to-regexp
$ node server.js

$ curl http://localhost:3000/entries
entry list html

$ curl http://localhost:3000/entries/123
entry item html : 123

$ curl http://localhost:3000/foo        
not found