code: function defaults(targ, _defs) {
      [].slice.call(arguments, 1).forEach(function (def) {
          Object.keys(def).forEach(function (key) {
              if (!targ.hasOwnProperty(key)) {
                  targ[key] = def[key];
              }
          });
      });
  }
docs: Update targ with attributes from _defs. Any existing attributes on targ are untouched.