const graph = {

  a: { b: 5, c: 2 },

  b: { a: 5, c: 7, d: 8 },

  c: { a: 2, b: 7, d: 4, e: 8 },

  d: { b: 8, c: 4, e: 6, f: 4 },

  e: { c: 8, d: 6, f: 3 },

  f: { e: 3, d: 4 },

};

​

const formatGraph = (g) => {

  const tmp = {};

  Object.keys(g).forEach((k) => {

    const obj = g[k];

    const arr = [];

    Object.keys(obj).forEach((v) => arr.push({ vertex: v, cost: obj[v] }));

    tmp[k] = arr;

  });

  return tmp;

};

​

const dijkstra = (graph, start, end) => {

  var map = formatGraph(graph);

​

  var visited = [];

  var unvisited = [start];

  var shortestDistances = { [start]: { vertex: start, cost: 0 } };

​

  var vertex;

  while ((vertex = unvisited.shift())) {