code: function fdmap(left, right) {
          // PhantomJS does not support es6 Object.assign
          //left = Object.assign(left, right);
          Object.keys(right).forEach(function(key) {
            left[key] = right[key];
          });
          return left;
        }
docs: Since our collection options do not specify cloning, this is only safe because we have cloned internal objects with dataOptions before modifying them.