src/avl-tree.js
function minValueNode(root) {
  var current = root;
  while (current.left) {
    current = current.left;
  }
  return current;
}
function minValueNode(root) {
  var current = root;
  while (current.left) {
    current = current.left;
  }
  return current;
}
function minValueNode ( root ) { var current = root ; while ( current . left ) { current = current . left ; } return current ; }
Gets the minimum value node, rooted in a particular node.

@private
@param {Node} root The node to search.
@return {Node} The node with the minimum key in the tree.
Gets the minimum value node rooted in a particular node .