docs: function urlJoin() {
      var args = Array.prototype.slice.call(arguments),
          prefixDoubleSlash = false,
          url;
  
      // Remove empty item at the beginning
      if (args[0] === '') {
          args.shift();
      }
  
      // Handle schemeless protocols
      if (args[0].indexOf('//') === 0) {
          prefixDoubleSlash = true;
      }
  
      // join the elements using a slash
      url = args.join('/');
  
      // Fix multiple slashes
      url = url.replace(/(^|[^:])\/\/+/g, '$1/');
  
      // Put the double slash back at the beginning if this was a schemeless protocol
      if (prefixDoubleSlash) {
          url = url.replace(/^\//, '//');
      }
  
      url = deduplicateSubDir(url);
      return url;
  }