Simple route parser to extract parameters from a url given a format

gistfile1.js

var SimpleRouteParser = function(format) {
  var namedParam = /\/(:(\w+))/g,
    names,
    route,
    setFormat = function(format) {
      if (!format) throw new Error('Please specify the url format');

      names = [];

      route = format.replace(namedParam, function(match, param, name) {
        //Store names to build the hash later
        names.push(name);
        return '/([^/?]+)';
      });
      route = new RegExp('^' + route + '(?:\\?([\\s\\S]*))?$');
    },
    parseQueryString = function(storeIn, queryString) {
      var queryRegex = /\&?([^=]+)\=([^&]+)/g;
      while ((parsed = queryRegex.exec(queryString)) !== null) {
        storeIn[parsed[1]] = parsed[2];
      }
    };

  setFormat(format || '/');

  return {
    parse: function(url) {
      var parsed, i, hash = {};

      if (!route || !route.exec) throw new Error('Error getting the route Regex');

      parsed = route.exec(url);

      if (parsed) {

        //Match names to parameters
        for (i = 1; i <= names.length; i += 1) {
          hash[names[i - 1]] = parsed[i];
        }

        if (parsed.length > names.length) {
          //parseQueryString could return an object and extend hash with the result
          //But to not add underscore or something like that and dont iterate here I just send the hash
          parseQueryString(hash, parsed[i]);
        }
      }


      return hash;
    },
    format: setFormat
  };
};

//Usage
var route = new SimpleRouteParser('/:version/api/:collecton/:id');

console.log(route.parse('/6/api/listings/3?sort=desc&limit=10'));
console.log(route.parse('/6/api/listings/3'));

route.format('/');
console.log(route.parse('/6/api/listings/3?sort=desc&limit=10'));