Find the second largest element in a linked list in node js

Js program for Find the second largest element in a linked list. Here problem description and explanation.

// Node JS Program for
// Find second largest number in linked list

// Linked list node
class LinkNode
{
	constructor(data)
	{
		this.data = data;
		this.next = null;
	}
}
class SingleLL
{
	constructor()
	{
		this.head = null;
		this.tail = null;
	}
	// Add new node at the end of linked list
	insert(value)
	{
		// Create a new node
		var node = new LinkNode(value);
		if (this.head == null)
		{
			this.head = node;
		}
		else
		{
			this.tail.next = node;
		}
		this.tail = node;
	}
	// Display linked list element
	display()
	{
		if (this.head == null)
		{
			return;
		}
		var temp = this.head;
		// iterating linked list elements
		while (temp != null)
		{
			process.stdout.write(temp.data + " → ");
			// Visit to next node
			temp = temp.next;
		}
		console.log("null");
	}
	// Find second largest node in linked list
	secondLargest()
	{
		if (this.head == null)
		{
			console.log("\nEmpty linked list");
			return;
		}
		// Display given linked list element
		this.display();
		// Define some auxiliary variables
		var big = null;
		var result = null;
		var temp = this.head;
		// iterating linked list elements
		while (temp != null)
		{
			if (big == null)
			{
				// Get first node
				big = temp;
			}
			else if (big.data < temp.data)
			{
				// Get a new big node
				// Get second largest node
				result = big;
				// Get current largest node
				big = temp;
			}
			else if (big.data != temp.data)
			{
				if (result == null)
				{
					// If in case second largest node empty
					result = temp;
				}
				else if (result.data < temp.data)
				{
					// Get new second largest node
					result = temp;
				}
			}
			// Visit to next node
			temp = temp.next;
		}
		if (result == null)
		{
			// When second largest node are not exist in linked list
			console.log("Second largest element are not exist");
		}
		else
		{
			console.log("Second largest : " + result.data);
		}
	}
}

function main()
{
	// Testing linked list
	var list1 = new SingleLL();
	var list2 = new SingleLL();
	var list3 = new SingleLL();
	var list4 = new SingleLL();
	// Add node in first linked list
	// 6 → 4 → 5 → 10 → 3 → 7 → 9 → 2 → 8 → null
	list1.insert(6);
	list1.insert(4);
	list1.insert(5);
	list1.insert(10);
	list1.insert(3);
	list1.insert(7);
	list1.insert(9);
	list1.insert(2);
	list1.insert(8);
	list1.secondLargest();
	// Add node in second linked list
	// 1 → 1 → 4 → 2 → 3 → 1 → null
	list2.insert(1);
	list2.insert(1);
	list2.insert(4);
	list2.insert(2);
	list2.insert(3);
	list2.insert(1);
	list2.secondLargest();
	// Add node in third linked list
	// 2 → 6 → 8 → 4 → 8 → 3 → 3 → 2 → null
	list3.insert(2);
	list3.insert(6);
	list3.insert(8);
	list3.insert(4);
	list3.insert(8);
	list3.insert(3);
	list3.insert(3);
	list3.insert(2);
	list3.secondLargest();
	// Add node in fourth linked list
	list4.insert(2);
	list4.insert(2);
	list4.insert(2);
	// 2 → 2 → 2 → null
	list4.secondLargest();
}
// Start program execution
main();

Output

6 → 4 → 5 → 10 → 3 → 7 → 9 → 2 → 8 → null
Second largest : 9
1 → 1 → 4 → 2 → 3 → 1 → null
Second largest : 3
2 → 6 → 8 → 4 → 8 → 3 → 3 → 2 → null
Second largest : 6
2 → 2 → 2 → null
Second largest element are not exist