Find indegree and outdegree of a directed graph in node js

Js program for Find indegree and outdegree of a directed graph. Here problem description and other solutions.

/*
    Node JS Program for 
    Show degree of vertex in directed graph
*/
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++)
			{
				// Set initial node value
				this.node[index] = new Vertices(index);
			}
		}
	}
	//  Handling the request of adding new edge
	addEdge(start, last)
	{
		if (start >= 0 && start < this.size && 
            last >= 0 && last < this.size)
		{
			// Safe connection
			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;
		}
		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;
				}
			}
		}
	}
	// Find indegree and outdegree of 
	// each nodes of a given graph
	findDegree(indegree, outdegree)
	{
		var temp = null;
		var length = 0;
		for (var i = 0; i < this.size; ++i)
		{
			temp = this.node[i].next;
			length = 0;
			while (temp != null)
			{
				// Update indegree
				indegree[temp.id]++;
				temp = temp.next;
				length++;
			}
			// Set outdegree value
			outdegree[i] = length;
		}
	}
	showDegree()
	{
		if (this.node != null)
		{
			var indegree = Array(this.size).fill(0);
			var outdegree = Array(this.size).fill(0);
			// Set zero degree
			for (var i = 0; i < this.size; i++)
			{
				indegree[i] = 0;
				outdegree[i] = 0;
			}
			// Find degree
			this.findDegree(indegree, outdegree);
			console.log("\n");
			// Display result
			for (var i = 0; i < this.size; ++i)
			{
				console.log("Node [" + i + 
                            "] indegree [" + indegree[i] + 
                            "] outdegree [" + outdegree[i] + "]");
			}
		}
		else
		{
			process.stdout.write("Empty Graph");
		}
	}
}

function main()
{
	// 6 implies the number of nodes in graph
	var g = new Graph(6);
	// Connected two node with Edges
	g.addEdge(0, 1);
	g.addEdge(0, 2);
	g.addEdge(0, 5);
	g.addEdge(2, 3);
	g.addEdge(3, 1);
	g.addEdge(4, 0);
	g.addEdge(4, 1);
	g.addEdge(5, 0);
	g.addEdge(5, 2);
	g.printGraph();
	// Test
	g.showDegree();
}
// Start program execution
main();

Output

Adjacency list of vertex 0 :  1 2 5
Adjacency list of vertex 1 :
Adjacency list of vertex 2 :  3
Adjacency list of vertex 3 :  1
Adjacency list of vertex 4 :  0 1
Adjacency list of vertex 5 :  0 2

Node [0] indegree [2] outdegree [3]
Node [1] indegree [3] outdegree [0]
Node [2] indegree [2] outdegree [1]
Node [3] indegree [1] outdegree [1]
Node [4] indegree [0] outdegree [2]
Node [5] indegree [1] outdegree [2]