bfs.js

/*
1.Create an adjacency list to represent a graph of alphabetical letters as follows:
   A 
  B  C 
 D E   H
   F G
2. Write a function that takes a graph, a node (a letter) as a starting point, and lastly a node to search for. Return true if exists, and false if it does not



  
*/

const graph = {
	A: ['B','C'],
	B: ['D','E'],
	C: ['H'],
	D: [],
	E: ['F','G'],
	F: [],
	G: [],
	H: ['G']
}

class Queue {
    constructor() {
      this.items = [];
    }

    enqueue(nodeList) {
      this.items = this.items.concat(nodeList);
    }

    dequeue() {
      return this.items.shift();
    }

    isEmpty() {
      return this.items.length === 0;
    }
}

var nodeNotVisited = (list,item) => {
	if (list.indexOf(item) === -1) {
		return true;
	}
	return false;
};

function bfs(graph,startingNode,targetNode){
	let queue = new Queue();
	visitedNodes = [];
	queue.enqueue(graph[startingNode]);
  while (!queue.isEmpty()){
  	let node = queue.dequeue();
  	if(nodeNotVisited(visitedNodes,node)){
  		if(node === targetNode){
  			return true;
  		}
  		else{
  			visitedNodes.push(node);
  			queue.enqueue(graph[node]);
  		}
  	}
  }
  return false;
}


bfs(graph,'A','Z');