source/Router.js
function Router (routes) {
  this._routes         = [];
  this._not_found      = null;
  this._not_found_path = '/404';
  
  if (arguments.length === 1) {
    this.addRoutes(routes);
  }
}
function Router (routes) {
  this._routes         = [];
  this._not_found      = null;
  this._not_found_path = '/404';
  
  if (arguments.length === 1) {
    this.addRoutes(routes);
  }
}
Router ====== constructor ----------- create a router ### optional arguments **routes**  : routes to add