objectid

objectid.js

function ObjectId () {
  this.str = this.genID();
}

ObjectId.prototype.genID = function () {
  var float32 = 16777216;
  var int16 = 65536;

  var ts = Math.floor(Date.now() / 1000).toString(16);
  var mid =  Math.floor(Math.random() * (int16)).toString(16);
  var pid = Math.floor(Math.random() * (float32)).toString(16);
  var counter = Math.floor(Math.random() * (float32)).toString(16);

  return '00000000'.substr(0, 8 - ts.length) + ts +
    '000000'.substr(0, 6 - mid.length) + mid +
    '0000'.substr(0, 4 - pid.length) + pid +
    '000000'.substr(0, 6 - counter.length) + counter;
};

ObjectId.prototype.getTimestamp = function () {
  return new Date(parseInt(this.valueOf().slice(0, 8), 16) * 1000);
};

ObjectId.prototype.toString = function () {
  return 'ObjectId("' + this.str + '")';
};

ObjectId.prototype.valueOf = function () {
  return this.str;
};

//usage
var o = new ObjectId();
console.log(o.getTimestamp());
console.log(o.toString());
console.log(o.valueOf());
console.log(o.str);