Graph TraversalDFS-BFS.js

class Graph{
    constructor(){
        this.adjacencyList = {};
    }
    addVertex(vertex){
        if(!this.adjacencyList[vertex]) this.adjacencyList[vertex] = [];
    }
    addEdge(v1,v2){
        this.adjacencyList[v1].push(v2);
        this.adjacencyList[v2].push(v1);
    }
    removeEdge(vertex1,vertex2){
        this.adjacencyList[vertex1] = this.adjacencyList[vertex1].filter(
            v => v !== vertex2
        );
        this.adjacencyList[vertex2] = this.adjacencyList[vertex2].filter(
            v => v !== vertex1
        );
    }
    removeVertex(vertex){
        while(this.adjacencyList[vertex].length){
            const adjacentVertex = this.adjacencyList[vertex].pop();
            this.removeEdge(vertex, adjacentVertex);
        }
        delete this.adjacencyList[vertex]
    }
    depthFirstRecursive(start){
        const result = [];
        const visited = {};
        const adjacencyList = this.adjacencyList;

        (function dfs(vertex){
            if(!vertex) return null;
            visited[vertex] = true;
            result.push(vertex);
            adjacencyList[vertex].forEach(neighbor => {
                if(!visited[neighbor]){
                    return dfs(neighbor)
                }
            });
        })(start);

        return result;
    }
    depthFirstIterative(start){
        const stack = [start];
        const result = [];
        const visited = {};
        let currentVertex;

        visited[start] = true;
        while(stack.length){
            currentVertex = stack.pop();
            result.push(currentVertex);

            this.adjacencyList[currentVertex].forEach(neighbor => {
               if(!visited[neighbor]){
                   visited[neighbor] = true;
                   stack.push(neighbor)
               } 
            });
        }
        return result;
    }
    breadthFirst(start){
        const queue = [start];
        const result = [];
        const visited = {};
        let currentVertex;
        visited[start] = true;

        while(queue.length){
            currentVertex = queue.shift();
            result.push(currentVertex);
           

            this.adjacencyList[currentVertex].forEach(neighbor => {
                if(!visited[neighbor]){
                    visited[neighbor] = true;
                    queue.push(neighbor);
                }
            });
        }
        return result;
    }
}



let g = new Graph();

g.addVertex("A")
g.addVertex("B")
g.addVertex("C")
g.addVertex("D")
g.addVertex("E")
g.addVertex("F")


g.addEdge("A", "B")
g.addEdge("A", "C")
g.addEdge("B","D")
g.addEdge("C","E")
g.addEdge("D","E")
g.addEdge("D","F")
g.addEdge("E","F")

//          A
//        /   \
//       B     C
//       |     |
//       D --- E
//        \   /
//          F

// QUEUE: []
// RESULT: [A, B, C, D, E, F]