floyd-warshall.js

const floydWarshall = graph => {
  const dist = []
  const { length } = graph

  for (let i = 0; i < length; i++) {
    dist[i] = []
    for (let j = 0; j < length; j++) {
      if (i === j) {
        dist[i][j] = 0
      } else if (!isFinite(graph[i][j])) {
        dist[i][j] = Infinity
      } else {
        dist[i][j] = graph[i][j]
      }
    }
  }

  for (let k = 0; k < length; k++) {
    for (let i = 0; i < length; i++) {
      for (let j = 0; j < length; j++) {
        if (dist[i][k] + dist[k][j] < dist[i][j]) {
          dist[i][j] = dist[i][k] + dist[k][j]
        }
      }
    }
  }
  return dist
}

// test
const INF = Infinity
const graph = [
  [INF, 2, 4, INF, INF, INF],
  [INF, INF, 2, 4, 2, INF],
  [INF, INF, INF, INF, 3, INF],
  [INF, INF, INF, INF, INF, 2],
  [INF, INF, INF, 3, INF, 2],
  [INF, INF, INF, INF, INF, INF]
]

const dist = floydWarshall(graph)

let s = ''
for (let i = 0; i < dist.length; ++i) {
  s = '';
  for (var j = 0; j < dist.length; ++j) {
    if (dist[i][j] === INF) s += 'INF ';
    else s += dist[i][j] + '   '
  }
  console.log(s)
}