Saving tiles locally

gistfile1.txt

var request = require("request"),
    fs = require("fs"),
    xyz = require("xyz-affair"),
    queue = require("queue-async")(10), //max concurrency
    path = require("path"),
    mkdirp = require("mkdirp");

var bounds = [
  [
    -74.00596618652344,
    40.64417760251725,
  ],
  [
    -73.90502929687499,
    40.797957124643666
  ]
];

var zoom = 16;

var tiles = xyz(bounds,zoom),
    numTiles = tiles.length;

tiles.forEach(function(t,i){
  queue.defer(getTile,t,i);
});

queue.awaitAll(function(err,results){
  console.log(err);
});

function getTile(tile,c,cb) {

  var fn = path.join(tile.z+"",tile.x+"",tile.y+".png"),
      url = "http://sometileurl.com/"+fn;

  c++;

  mkdirp.sync(path.join(tile.z+"",tile.x+""));
  request(url)
    .on('error', function(err) {
      cb(err,console.log(err));
    })
    .on('end',function(){
      console.log(c+"/"+numTiles);
      cb(null,null);
    })
    .pipe(fs.createWriteStream(fn));

}