JS: Implementation of Graph

graph.js

class Graph {
  constructor() {
    this.adjList = new Map();
  }

  addVertex(v) {
    this.adjList.set(v, []);
    return this;
  }

  addEdge(v, w) {
    this.adjList.get(v).push(w);
    this.adjList.get(w).push(v);
    return this;
  }

  toString() {
    var paths = '';
    for(var key of this.adjList.keys()) {
      var path = `${key} -> `;
      for(var value of this.adjList.get(key)) {
        path += `${value} `;
      }
      paths += `${path}\n`;
    }
    return paths;
  }

  bfs(startingVertex, cb) {
    var queue = new Queue;
    var visited = new Set;
    queue.enqueue(startingVertex);
    visited.add(startingVertex);

    while(!queue.isEmpty()) {
      var vertex = queue.dequeue();
      cb(vertex);

      var neighbours = this.adjList.get(vertex);

      for(var i = 0; i < neighbours.length; i++) {
        if(!visited.has(neighbours[i])) {
          queue.enqueue(neighbours[i]);
          visited.add(neighbours[i]);
        }
      }
    }
  }

  dfs(startingVertex, cb) {
    var visited = new Set;

    function recur(vertex, adjList) {
      visited.add(vertex);
      cb(vertex);
      var neighbours = adjList.get(vertex);

      for(var i = 0; i < neighbours.length; i++) {
        if(!visited.has(neighbours[i])) {
          recur(neighbours[i], adjList)
        }
      }
    }
    recur(startingVertex, this.adjList);
  }
}

var graph = new Graph();
var vertices = ['A', 'B', 'C', 'D', 'E', 'F'];

for(var i = 0; i < vertices.length; i++) {
  graph.addVertex(vertices[i]);
}

graph
  .addEdge('A', 'B')
  .addEdge('A', 'D')
  .addEdge('A', 'E')
  .addEdge('B', 'C')
  .addEdge('D', 'E')
  .addEdge('E', 'F')
  .addEdge('E', 'C')
  .addEdge('C', 'F');

console.log(graph.toString());
console.log('BFS')
graph.bfs('A', console.log);
console.log('DFS')
graph.dfs('A', console.log);