Directed Graph Javascript Implementation

graph_adjacency_list.js

//Space Complexity: O(V + E)
class Graph {
  constructor() {
    this.vertices = new Map();
  }
  
  //O(V) time complexity of Map.prototype.set
  addVertex(v) {
    this.vertices.set(v, [])
  }
  
  //O(V) time complexity of Map.prototype.delete
  removeVertex(v){
    this.vertices.delete(v);
  }
  
  //O(V) time complexity of Map.prototype.get
  addEdge(from, to) {
    this.vertices.get(from).push(to);

    //add this for an undirected graph:
    //this.vertices.get(to).push(from);
  }
  
  //O(V + e) e = edges of given Vertex, V = time complexity of Map.prototype.get
  removeEdge(from, to) {
    let edges = [];
    
    for(let e of this.vertices.get(from)) {
      if(e !== to) {
        edges.push(e)
      }
    }
    
    this.vertices.get(from) = edges;
  }
}

let g = new Graph();
g.addVertex('A');
g.addVertex('B');
g.addVertex('C');
g.addVertex('D');

g.addEdge('B', 'A')
g.addEdge('C', 'A')
// g.removeEdge('B', 'A')
g.removeVertex('A')
//prints "A"
console.log(g)