Router.js

define(function (require) {

    var $ = require('jquery')
        , underscore = require('underscore')
        , Events = require('./Events')
        , History = require('./History')

    // Routers map faux-URLs to actions, and fire events when routes are
    // matched. Creating a new one sets its `routes` hash, if not set statically.
    var Router = function (options) {
        options || (options = {});
        if (options.routes) this.routes = options.routes;
        this._bindRoutes();
        this.initialize.apply(this, arguments);
    };

    // Cached regular expressions for matching named param parts and splatted
    // parts of route strings.
    var namedParam = /:\w+/g
        , splatParam = /\*\w+/g
        , escapeRegExp = /[-[\]{}()+?.,\\^$|#\s]/g
        ;

    Router.prototype = {

        // Initialize is an empty function by default. Override it with your own
        // initialization logic.
        initialize:function () {},

        // Manually bind a single named route to a callback. For example:
        //
        //     this.route('search/:query/p:num', 'search', function(query, num) {
        //       ...
        //     });
        //
        route:function (route, name, callback) {
            History.instance || (History.instance = new History);
            if (!_.isRegExp(route)) route = this._routeToRegExp(route);
            if (!callback) callback = this[name];
            History.instance.route(route, _.bind(function (fragment) {
                var args = this._extractParameters(route, fragment);
                callback && callback.apply(this, args);
                this.trigger.apply(this, ['route:' + name].concat(args));
                History.instance.trigger('route', this, name, args);
            }, this));
            return this;
        },

        // Simple proxy to `History.instance` to save a fragment into the history.
        navigate:function (fragment, options) {
            History.instance.navigate(fragment, options);
        },

        // Bind all defined routes to `History.instance`. We have to reverse the
        // order of the routes here to support behavior where the most general
        // routes can be defined at the bottom of the route map.
        _bindRoutes:function () {
            if (!this.routes) return;
            var routes = [];
            for (var route in this.routes) {
                routes.unshift([route, this.routes[route]]);
            }
            for (var i = 0, l = routes.length; i < l; i++) {
                this.route(routes[i][0], routes[i][1], this[routes[i][1]]);
            }
        },

        // Convert a route string into a regular expression, suitable for matching
        // against the current location hash.
        _routeToRegExp:function (route) {
            route = route.replace(escapeRegExp, '\\$&')
                .replace(namedParam, '([^\/]+)')
                .replace(splatParam, '(.*?)');
            return new RegExp('^' + route + '$');
        },

        // Given a route, and a URL fragment that it matches, return the array of
        // extracted parameters.
        _extractParameters:function (route, fragment) {
            return route.exec(fragment).slice(1);
        }

    };

    _.extend(Router.prototype, Events);

    return Router;

});