A simple router class in JavaScript using callbacks (not events)

Router.js

/**
 * # Simple Router
 * A JavaScript router class.
 *
 * #### Examples
 *     var appRouter, func,
 *         Router = require("Router");
 *
 *     appRouter = new Router();
 *     appRouter.get("/", indexMethod);
 *     appRouter.post("/save", saveMethod);
 *     appRouter.get(/foo/, fooMethod);
 *
 *     func = appRouter.getRoute("get", "/");
 *     func();
 *     func = appRouter.getRoute("get", "/123/foobar/");
 *     func();
 */
(function() {
  var get_routes, Router;

  /**
   * ### get_routes()
   * **Private** function to find all the routes accosiated with a specific
   * route method.
   *
   * #### Arguments
   * - context: _object_ - the context that stores the routes variable (ex. the `this` keyword)
   * - method: _string_ - the routing method (ex. 'get', 'post')
   */
  get_routes = function(context, method) {
    return context.routes[method] || (context.routes[method] = []);
  };

  /**
   * ## Router class
   */
  Router = (function() {
    function Router() {
      this.routes = {
        get: [],
        post: []
      };
    }

    /**
     * ### getRoute()
     * Returns a route for a specific method and url
     *
     * #### Arguments
     * - method: _string_ - the HTTP method (ex. 'get', 'post')
     * - url: _string_ - the URL in question (ex. 'http://example.com/')
     */
    Router.prototype.getRoute = function(method, url) {
      var r, rl, i, route, match;
      r = get_routes(this, method);
      for (i = 0, rl = r.length; i < rl; i++) {
        route = r[i];
        if (route.type === "string") {
          if (route.url === url) {
            return [url, route.callback];
          }
        }
        else if (route.type === "regexp") {
          if (match = route.url.exec(url)) {
            return [match, route.callback];
          }
        }
        else {
          throw TypeError("unknown routing url type");
        }
      }
      return null;
    };

    /**
     * ### set()
     * Set a route. The URL in question can be a string or Regexp.
     * Retuns itself so chaning can be used.
     *
     * #### Arguments
     * - method: _string_ - the HTTP method (ex. 'get', 'post')
     * - url: _string, regexp_ - the URL for the route
     * - callback: _function_ - the function to use for this route
     */
    Router.prototype.set = function(method, url, callback) {
      get_routes(this, method).push({
        url: url,
        callback: callback,
        type: Object.prototype.toString.call(url).slice(8,1).toLowerCase()
      });
      return this;
    };

    /**
     * ### get()
     * Adds a route for the 'get' and 'head' methods with the URL in question
     *
     * #### Arguments
     * - url: _string, regexp_ - the URL in question
     * - callback: _function_ - the function to use for this route
     */
    Router.prototype.get = function(url, callback) {
      this.set('get', url, callback);
      this.set('head', url, callback);
      return this;
    };

    /**
     * ### post()
     * Adds a route for the 'post' method with the URL in question
     *
     * #### Arguments
     * - url: _string, regexp_ - the URL in question
     * - callback: _function_ - the function to use for this route
     */
    Router.prototype.post = function(url, callback) {
      this.set('post', url, callback);
      return this;
    };

    return Router;
  })();

  // Check that we can export as a module.
  // If not attach to the window object.
  if (module != null) {
    module.exports = Router;
  }
  else {
    window.Router = Router;
  }
})();