Everybody love Object pool !

Pool.js

function Pool (size, entity, params) {
    "use strict";

    this.item = [];
    this.dead = [];
    var that = this;
    this.forceIndex = 0;

    for (var i = size - 1; i >= 0; i--) {
        var newItem = new entity(params);
        newItem.active = false;
        newItem.pool = this;
        newItem.destroy = function () {
            this.active = false;
            that.dead.push(this);
        };
        this.item.push(newItem);
        this.dead.push(newItem);
    };

}

Pool.prototype.create = function(callback,force) {
    var item = this.dead.shift();
    if (!item) {
        if (force) {
            item = this.item[this.forceIndex];
            this.forceIndex++;
            this.forceIndex %= this.item.length();
        } else {
            return false
        }
    }
    callback(item);
    item.active = true;
};

Pool.prototype.forEach = function(callback) {
    for (var i = this.item.length - 1; i >= 0; i--) {
        callback(this.item[i], this.item[i].active);
    };
};

Pool.prototype.forEachLiving = function(callback) {
    for (var i = this.item.length - 1; i >= 0; i--) {
        if (this.item[i].active) {
            callback(this.item[i]);
        }
    }
};

Pool.prototype.forEachDead = function(callback) {
    for (var i = this.dead.length - 1; i >= 0; i--) {
        callback(this.dead[i]);
    }
};