Insertion at end of circular doubly linked list in node js

Js program for Insertion at end of circular doubly linked list. Here problem description and other solutions.

// Node JS Program 
// Insert node at end of circular doubly linked list

// Define class of linked list Node
class LinkNode
{
	constructor(data)
	{
		// Set node value
		this.data = data;
		this.next = null;
		this.prev = null;
	}
}
class CircularDLL
{
	constructor()
	{
		this.head = null;
		this.tail = null;
	}
	// Insert node at end of circular doubly linked list
	insert(value)
	{
		// Create a node
		var node = new LinkNode(value);
		if (this.head == null)
		{
			// First node of linked list
			this.head = node;
			this.tail = node;
			node.next = node;
			node.prev = node;
		}
		else
		{
			node.next = this.head;
			node.prev = this.tail;
			this.head.prev = node;
			this.tail.next = node;
			// Set new last node
			this.tail = node;
		}
	}
	headToTail()
	{
		if (this.head == null)
		{
			console.log("Empty linked list");
		}
		else
		{
			var temp = this.head;
			console.log("\nNode Form Front to Rear :");
			while (temp != null)
			{
				process.stdout.write("  " + temp.data);
				temp = temp.next;
				if (temp == this.head)
				{
					return;
				}
			}
		}
	}
	tailToHead()
	{
		if (this.tail == null)
		{
			process.stdout.write("Empty linked list");
		}
		else
		{
			var temp = this.tail;
			console.log("\nNode Form Rear to Front :");
			while (temp != null)
			{
				process.stdout.write("  " + temp.data);;
				temp = temp.prev;
				if (temp == this.tail)
				{
					return;
				}
			}
		}
	}
}

function main()
{
	var cdll = new CircularDLL();
	// Add following linked list nodes
	cdll.insert(1);
	cdll.insert(2);
	cdll.insert(3);
	cdll.insert(4);
	cdll.insert(5);
	cdll.insert(6);
	// Display node
	cdll.headToTail();
	cdll.tailToHead();
}
// Start program execution
main();

Output

Node Form Front to Rear :
  1  2  3  4  5  6
Node Form Rear to Front :
  6  5  4  3  2  1