graphDFS.js

class Graph {
    constructor() {
      this.vertices = []
      this.adjacencyList = {}
    }
  
    addVertex(vertex) {
      this.vertices.push(vertex)
      this.adjacencyList[vertex] = []
    }
  
    addEdge(vertex1, vertex2) {
      this.adjacencyList[vertex1].push(vertex2)
      this.adjacencyList[vertex2].push(vertex1)
    }
  
    dfs(startingVertex) {
      const visited = {}
      const result = []
  
      const dfsHelper = (vertex) => {
        if (!vertex) {
          return null
        }
        visited[vertex] = true
        result.push(vertex)
        this.adjacencyList[vertex].forEach((neighbor) => {
          if (!visited[neighbor]) {
            return dfsHelper(neighbor)
          }
        })
      }
  
      dfsHelper(startingVertex)
      return result
    }
  }
  
 
  const graph = new Graph()
  graph.addVertex("A")
  graph.addVertex("B")
  graph.addVertex("C")
  graph.addVertex("D")
  graph.addEdge("A", "B")
  graph.addEdge("A", "C")
  graph.addEdge("B", "D")
  graph.addEdge("C", "D")
  
//   console.log(graph.dfs("A"))