网上看到一个路由的实现

网上看到一个精致的路由的实现，大概原理是：
轮询路由的状态，在改变的时候，当match到对应的预设好的路由时，执行其注册的回调函数。其实是还可以加上视图view的。他的代码如下：

var Router = {
    routes: [],
    mode: null,
    root: '/',
    config: function (options) {
        this.mode = options && options.mode && options.mode == 'history'
        && !!(history.pushState) ? 'history' : 'hash';
        this.root = options && options.root ? '/' + this.clearSlashes(options.root) + '/' : '/';
        return this;
    },
    getFragment: function () {
        var fragment = '';
        if (this.mode === 'history') {
            fragment = this.clearSlashes(decodeURI(location.pathname + location.search));
            fragment = fragment.replace(/\?(.*)$/, '');
            fragment = this.root != '/' ? fragment.replace(this.root, '') : fragment;
        } else {
            var match = window.location.href.match(/#(.*)$/);
            fragment = match ? match[1] : '';
        }
        return this.clearSlashes(fragment);
    },
    clearSlashes: function (path) {
        return path.toString().replace(/\/$/, '').replace(/^\//, '');
    },
    add: function (re, handler) {
        if (typeof re == 'function') {
            handler = re;
            re = '';
        }
        this.routes.push({re: re, handler: handler});
        return this;
    },
    remove: function (param) {
        for (var i = 0, r; i < this.routes.length, r = this.routes[i]; i++) {
            if (r.handler === param || r.re.toString() === param.toString()) {
                this.routes.splice(i, 1);
                return this;
            }
        }
        return this;
    },
    flush: function () {
        this.routes = [];
        this.mode = null;
        this.root = '/';
        return this;
    },
    check: function (f) {
        var fragment = f || this.getFragment();
        for (var i = 0; i < this.routes.length; i++) {
            var match = fragment.match(this.routes[i].re);
            if (match) {
                match.shift();
                this.routes[i].handler.apply({}, match);
                return this;
            }
        }
        return this;
    },
    listen: function () {
        var self = this;
        var current = self.getFragment();
        var fn = function () {
            if (current !== self.getFragment()) {
                current = self.getFragment();
                self.check(current);
            }
        }
        clearInterval(this.interval);
        this.interval = setInterval(fn, 50);
        return this;
    },
    navigate: function (path) {
        path = path ? path : '';
        if (this.mode === 'history') {
            history.pushState(null, null, this.root + this.clearSlashes(path));
        } else {
            window.location.href.match(/#(.*)$/);
            window.location.href = window.location.href.replace(/#(.*)$/, '') + '#' + path;
        }
        return this;
    }
}

// configuration
Router.config({mode: 'history'});

// returning the user to the initial state
Router.navigate();

// adding routes
Router
    .add(/about/, function () {
        console.log('about');
    })
    .add(/products\/(.*)\/edit\/(.*)/, function () {
        console.log('products', arguments);
    })
    .add(function () {
        console.log('default');
    })
    .check('/products/12/edit/22').listen();

// forwarding
Router.navigate('/about');