tree-async.js

function dirTree (filename, cb) {
  fs.lstat(filename, function (err, stat) {
    if (err) {
      return cb(err);
    }

    var info = {
      "path": filename,
      "name": path.basename(filename)
    };

    if (stat.isDirectory()) {
      info.type = "folder";
      fs.readdir(filename, function (err, children) {
        if (err) {
          return cb(err);
        }

        info.children = [];

        var browsed = 0;
        children.forEach(function (child, index) {
          dirTree(path.join(filename, child), function (err, childInfo) {
            if (err) {
              return cb(err);
            }

            info.children[index] = childInfo;
            
            if (++browsed === children.length) {
              cb(null, info);
            }
          });
        });
      });
    } else {
      info.type = "file";
      cb(null, info);
    }
  });
}