Simple coffee script Url class

Coffee script Url parser and builder

class Url
  constructor: (@path_and_qs=location.href) ->
    [@path, @qs_data] = @path_and_qs.split '?',2
    @qs = {}
    for elms in @qs_data.split '&'
      el = elms.split '=', 2
      @qs[el[0]] = el[1]

  build: ->
    ret = new Array
    for key,val of @qs
      ret.push "#{key}=#{val}"
    @path+'?'+ret.join '&'

url = new Url 'pero/lala?name=dux&age=jos'
url.qs['test'] = 123
alert url.build()

// compiles to JS

var Url, url;
Url = (function() {
  function Url(path_and_qs) {
    var el, elms, _i, _len, _ref, _ref2;
    this.path_and_qs = path_and_qs != null ? path_and_qs : location.href;
    _ref = this.path_and_qs.split('?', 2), this.path = _ref[0], this.qs_data = _ref[1];
    this.qs = {};
    _ref2 = this.qs_data.split('&');
    for (_i = 0, _len = _ref2.length; _i < _len; _i++) {
      elms = _ref2[_i];
      el = elms.split('=', 2);
      this.qs[el[0]] = el[1];
    }
  }
  Url.prototype.build = function() {
    var key, ret, val, _ref;
    ret = new Array;
    _ref = this.qs;
    for (key in _ref) {
      val = _ref[key];
      ret.push("" + key + "=" + val);
    }
    return this.path + '?' + ret.join('&');
  };
  return Url;
})();
url = new Url('pero/lala?name=dux&age=jos');
url.qs['test'] = 123;
alert(url.build());