rightRotation(node) {
    const oldParent = node.parent;
    const grandParent = oldParent.parent;

    if (grandParent) {
      // do something
    } else {
      this.root = node;
      node.parent = null;
      node.setRightAndUpdateParent(oldParent);
      oldParent.setLeftAndUpdateParent(null);
      // re-color
      node.color = BLACK;
      node.right.color = RED;
      node.left.color = RED;
    }
  }
Right rotation in-place

E.g. Right-rotate node 2

       3                   [2]
     /                   /    \
   [2]        =>       1        3
  /
 1

@param {TreeNode} node