pessimistic lock in nodejs

lock.js

function partial(f) {
  var args = Array.prototype.slice.call(arguments, 1)
  return function() {
    var remainingArgs = Array.prototype.slice.call(arguments)
    return f.apply(null, args.concat(remainingArgs))
  }
}

var options = {
  db: {
    safe: true
  }
}
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test', options);

var ThingSchema = new mongoose.Schema({
  count: Number,
});

var Thing = mongoose.model('Thing', ThingSchema);
var lock = true;

var id = "53e5fec1bcb589c92f6f38dd";
var doAdd = function(id){
  if(lock == false)
  {
    setTimeout(partial(arguments.callee, id), 0);
  }
  else{
    lock = false;
    Thing.findById(id, function(err, thing){ 
      console.log(thing.count)
      thing.count++;
      thing.save(function(){
        lock = true;
      });
    });
  }
};

doAdd(id);
doAdd(id);