Graph Coloring in JavaScript

graphColoring.js

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

  addVertex = (v) => {
    if (!this.adjList.has(v)) {
      this.adjList.set(v, []);
    }
  };

  addEdge = (v, u) => {
    this.adjList.get(v).push(u);
    this.adjList.get(u).push(v);
  };

  coloring = () => {
    const colored = new Map(); // Map to store vertex-color pairs
    const colors = ["red", "green", "blue", "yellow", "orange", "purple"]; // Array of available colors

    for (const key of this.adjList.keys()) {
      const adjColors = new Set();
      this.adjList.get(key).forEach((adjVertex) => {
        if (colored.has(adjVertex)) {
          adjColors.add(colored.get(adjVertex));
        }
      });

      for (const color of colors) {
        if (!adjColors.has(color)) {
          colored.set(key, color);
          break;
        }
      }
    }
    return [...colored]
  };
}

const graph = new Graph();
["A", "B", "C", "D", "E", "F"].forEach((vertex) => graph.addVertex(vertex));
graph.addEdge("A", "B");
graph.addEdge("A", "C");
graph.addEdge("B", "C");
graph.addEdge("B", "D");
graph.addEdge("C", "D");
graph.addEdge("C", "E");
graph.addEdge("D", "E");
graph.addEdge("E", "F");

console.log(graph.coloring());
/*
[
  [ 'A', 'red' ],
  [ 'B', 'green' ],
  [ 'C', 'blue' ],
  [ 'D', 'red' ],
  [ 'E', 'green' ],
  [ 'F', 'red' ]
]
*/