Remove duplicates from unsorted linked list in js

Js program for Remove duplicates from unsorted linked list. Here problem description and explanation.

// Node JS Program to 
// Delete duplicate nodes in unsorted linked list
class LinkNode
{
	constructor(data)
	{
		this.data = data;
		this.next = null;
	}
}
class LinkedList
{
	// Class constructors
	constructor()
	{
		this.head = null;
		this.tail = null;
	}
	// Insert new element at end position
	insert(value)
	{
		// Create new node
		var node = new LinkNode(value);
		if (this.head == null)
		{
			// Add first node
			this.head = node;
		}
		else
		{
			// Add new node at the last position
			this.tail.next = node;
		}
		// Make new tail 
		this.tail = node;
	}
	// Display all node value
	display()
	{
		if (this.head != null)
		{
			process.stdout.write("Linked List Element :");
			var temp = this.head;
			while (temp != null)
			{
				// Display node value
				process.stdout.write("  " + temp.data);
				// Visit to next node
				temp = temp.next;
			}
		}
		else
		{
			console.log("Empty Linked list");
		}
	}
	removeNode()
	{
		if (this.head == null)
		{
			// When linked list empty
			process.stdout.write("Empty Linked list");
		}
		else
		{
			// Auxiliary variable
			var temp = this.head;
			var hold = null;
			var initial = null;
			var current = null;
			// Outer loop
			while (temp != null)
			{
				// New last node
				this.tail = temp;
				current = temp;
				initial = current.next;
				// Inner loop
				// Remove all node which value is similar to temp node
				while (initial != null)
				{
					if (temp.data == initial.data)
					{
						// Get remove node
						hold = initial;
					}
					else
					{
						current = initial;
					}
					// Visit to next node
					initial = initial.next;
					if (hold != null)
					{
						current.next = initial;
						// remove node
						hold = null;
					}
				}
				// Visit to next node
				temp = temp.next;
			}
		}
	}
}

function main()
{
	// new linked list
	var task = new LinkedList();
	// Add tested element
	task.insert(1);
	task.insert(2);
	task.insert(9);
	task.insert(4);
	task.insert(9);
	task.insert(3);
	task.insert(1);
	task.insert(7);
	task.insert(2);
	task.insert(1);
	console.log("\nBefore Delete ");
	task.display();
	task.removeNode();
	console.log("\nAfter Delete ");
	task.display();
}
// Start program execution
main();

Output

Before Delete
Linked List Element :  1  2  9  4  9  3  1  7  2  1
After Delete
Linked List Element :  1  2  9  4  3  7