Adjacency list representation of undirected graph in node js

Js program for Adjacency list representation of undirected graph. Here problem description and explanation.

/*
    Node JS Program for 
    Undirected graph representation by using adjacency list 
*/
class AjlistNode
{
	constructor(id)
	{
		// Set value of node key
		this.id = id;
		this.next = null;
	}
}
class Vertices
{
	constructor(data)
	{
		this.data = data;
		this.next = null;
		this.last = null;
	}
}
class Graph
{
	constructor(size)
	{
		// Set value
		this.size = size;
		this.node = Array(size).fill(null);
		this.setData();
	}
	// Set initial node value
	setData()
	{
		if (this.size <= 0)
		{
			console.log("\nEmpty Graph");
		}
		else
		{
			for (var index = 0; index < this.size; index++)
			{
				this.node[index] = new Vertices(index);
			}
		}
	}
	// Connect two nodes
	connect(start, last)
	{
		var edge = new AjlistNode(last);
		if (this.node[start].next == null)
		{
			this.node[start].next = edge;
		}
		else
		{
			// Add edge at the end
			this.node[start].last.next = edge;
		}
		// Get last edge 
		this.node[start].last = edge;
	}
	//  Handling the request of adding new edge
	addEdge(start, last)
	{
		if (start >= 0 && start < this.size && 
            last >= 0 && last < this.size)
		{
			this.connect(start, last);
			if (start == last)
			{
				// When self loop
				return;
			}
			this.connect(last, start);
		}
		else
		{
			// When invalid nodes
			console.log("\nHere Something Wrong");
		}
	}
	printGraph()
	{
		if (this.size > 0)
		{
			// Print graph ajlist Node value
			for (var index = 0; index < this.size; ++index)
			{
				process.stdout.write("\nAdjacency list of vertex " + 
                                     index + " :");
				var temp = this.node[index].next;
				while (temp != null)
				{
					// Display graph node 
					process.stdout.write("  " + this.node[temp.id].data);
					// Visit to next edge
					temp = temp.next;
				}
			}
		}
	}
}

function main()
{
	// 5 implies the number of nodes in graph
	var g = new Graph(5);
	// Connect node with an edge
	g.addEdge(0, 1);
	g.addEdge(0, 2);
	g.addEdge(0, 4);
	g.addEdge(1, 2);
	g.addEdge(1, 4);
	g.addEdge(2, 3);
	g.addEdge(3, 4);
	// print graph element
	g.printGraph();
}
// Start program execution
main();

Output

Adjacency list of vertex 0 :  1  2  4
Adjacency list of vertex 1 :  0  2  4
Adjacency list of vertex 2 :  0  1  3
Adjacency list of vertex 3 :  2  4
Adjacency list of vertex 4 :  0  1  3