depthFirstSearch (array to map)

depthFirstSearch.js

// Initialize Depth First Search
// see https://en.wikipedia.org/wiki/Depth-first_search
const depthFirstSearch = (graph, source) => {
  console.log(source);

  for (let neighbour of graph.get(source)) {
    depthFirstSearch(graph, neighbour);
  }
};

// Either integer or string itself can be used here
const graph = [
  ["a", "b"],
  ["a", "c"],
  ["b", "d"],
  ["d", "f"],
  ["c", "e"]
];

const graphToDictionary = (graph) => {
  const adjacencyList = new Map();

  const keys = [...new Set(graph.flat())];

  keys.forEach((key) => {
    adjacencyList.set(key, []);
  });

  for (let i = 0; i < graph.length; i++) {
    adjacencyList.get(graph[i][0]).push(graph[i][1]);
  }

  return adjacencyList;
};

const dictionary = graphToDictionary(graph);

depthFirstSearch(dictionary, "a");