i can't found this function soucre code about site HOT 3 CLOSED

hexo.extend.helper.register('doc_sidebar', function(className){
  var type = this.page.canonical_path.split('/')[0];
  var sidebar = this.site.data.sidebar[type];
  var path = pathFn.basename(this.path);
  var result = '';
  var self = this;
  var prefix = 'sidebar.' + type + '.';

  _.each(sidebar, function(menu, title){
    result += '<strong class="' + className + '-title">' + self.__(prefix + title) + '</strong>';

    _.each(menu, function(link, text){
      var itemClass = className + '-link';
      if (link === path) itemClass += ' current';

      result += '<a href="' + link + '" class="' + itemClass + '">' + self.__(prefix + text) + '</a>';
    })
  });

  return result;
});