Simple router for the browser.

example.js

    var routes = {
      '/login': login
    , '/admin': adminIndex
    , '/404': function () { alert('404 not found'); router.navigate('/'); }   // mandatory
    };

    var router = new Router(routes);
    router.attach();
    router.initial('/login', true); // Forces going to login
    
    router.on('navigate:before', function () { console.log('AfterNavigate'); });
    router.on('navigate:after', function (section_id) { /* ... */ });

router.js

/*jshint browser:true, laxcomma:true, indent:2 */

/*
 * (c) 2013 Plastic Panda Snc
 * All rights reserved.
 *
 * License: BSD
 * Author: Simone Lusenti <simone@plasticpanda.com>
 */


(function (root) {
  
  var _getHash = function () {
    return window.location.hash.replace('#', '');
  };
  
  var _matchRoute = function (routes, url) {
    var ret = null;
    
    Object.keys(routes).forEach(function (routeDef) {
      // Case-sensitive non-regexp matching
      if (routeDef.toUpperCase() === url.toUpperCase()) {
        ret = [routeDef];
        return true;
      } else {
        var escapedRouteDef = RegExp.escape(routeDef);
        escapedRouteDef = escapedRouteDef.replace(/:[a-zA-Z][a-zA-Z0-9]/g, '(.+)');
        
        var matches = new RegExp(escapedRouteDef, 'ig');
        matches = matches.exec(url);
        
        if (matches !== null) {
          ret = [routeDef, matches.slice(1)];
          return true;
        }
      }
    });
    
    return ret;
  };
  
  
  var _hashChangeHandler = function (e) {
    this.trigger('navigate:before');
    
    var that = this;
    var routeDef = _matchRoute(this.routes, _getHash());
    
    if (!routeDef && _getHash() !== '/404') {
      this.navigate('/404');
    } else {
      var routeHandlers = this.routes[routeDef[0]]
        , _dispatchHandler = function (handler) {
            handler.apply(that, routeDef[1]);
          };
      
      if (Array.isArray(routeHandlers)) {
        routeHandlers.forEach(_dispatchHandler);
      } else {
        _dispatchHandler(routeHandlers);
      }
    }
    
    this.trigger('navigate:after');
  };
  
  
  function Router(routes) {
    if (typeof routes !== 'object') {
      throw new Error('Router constructor requires a routes parameter.');
    }
    
    this.routes = routes;
  }
  Router.prototype = Object.create(EventEmitter.prototype);
  
  
  Router.prototype.attach = function () {
    var that = this;
    window.addEventListener('hashchange', function (e) { _hashChangeHandler.call(that, e); }, false);
  };
  
  
  Router.prototype.initial = function (initialRoute, force) {
    if (initialRoute) {
      if (_getHash() === '' || force) {
        this.navigate(initialRoute);
      }
    }
  };
  
  
  Router.prototype.navigate = function (newHash) {
    window.location.hash = newHash;
  };
  
  
  window.Router = Router;
  
})(window);