Inorder traversal of binary tree with recursion in node js

Js program for Inorder traversal of binary tree with recursion. Here problem description and explanation.

/* 
  Node JS Program for
  inorder tree traversal of a Binary Tree
  using recursion
*/
// Binary Tree Node
class TreeNode
{
	constructor(data)
	{
		// Set node value
		this.data = data;
		this.left = null;
		this.right = null;
	}
}
class BinaryTree
{
	constructor()
	{
		this.root = null;
	}
	// Display Inorder view of binary tree
	inorder(node)
	{
		if (node != null)
		{
			// Visit left subtree
			this.inorder(node.left);
			//Print node value
			process.stdout.write("  " + node.data);
			// Visit right subtree
			this.inorder(node.right);
		}
	}
}

function main()
{
	// Create new tree
	var tree = new BinaryTree();
	/*
	    Make A Binary Tree
	    ----------------
	        15
	       /  \
	      24   54
	     /    /  \
	    35   62   13
	*/
	// Add tree TreeNode
	tree.root = new TreeNode(15);
	tree.root.left = new TreeNode(24);
	tree.root.right = new TreeNode(54);
	tree.root.right.right = new TreeNode(13);
	tree.root.right.left = new TreeNode(62);
	tree.root.left.left = new TreeNode(35);
	// Display Tree Node
	tree.inorder(tree.root);
}
// Start program execution
main();

Output

  35  24  15  62  54  13