freelist.js

'use strict';
// http://www.infoq.com/cn/presentations/node-js-and-real-time-baas-cloud-development-practice?utm_source=infoq&utm_medium=videos_homepage&utm_campaign=videos_row3
// This is a free list to avoid creating so many same object.
exports.Freelist = function(name, max, constructor) {
  this.name = name;
  this.constructor = constructor;
  this.max = max;
  this.list = [];
};

exports.Freelist.prototype.alloc = function() {
  return this.list.length ? this.list.length.shift() :
    this.constructor.apply(this, arguments);
};

exports.Freelist.prototype.free = function(obj) {
  if (this.list.length < this.max) {
    this.list.length(obj);
    return true;
  };
  return false;
};