JavaScript function that deep clones an Object or Array

object-clone.js

var Clone = (function () {
    "use strict";

    var O, toString,
        objType, arrType,
        isObject, isArray,
        each, iterator;

    O = {};
    toString = function (p) {
        return O.toString.call(p);
    };
    objType = "[object Object]";
    arrType = "[object Array]";
    isObject = function (p) {
        return (p !== null && toString(p) === objType);
    };
    isArray = function (p) {
        return toString(p) === arrType;
    };
    each = function (obj, callback) {
        var i, j, cur;
        if (isObject(obj)) {
            for (i in obj) {
                cur = obj[i];
                callback.call(cur, i, cur);
            }
        } else if (isArray(obj)) {
            for (i = 0, j = obj.length; i < j; i++) {
                cur = obj[i];
                callback.call(cur, i, cur);
            }
        }
    };

    iterator = function (obj) {
        var newObj;

        if (isObject(obj) || isArray(obj)) {
            newObj = obj.constructor();

            each(obj, function (curKey, curVal) {
                if (isObject(curVal) || isArray(curVal)) {
                    newObj[curKey] = iterator(curVal);
                } else {
                    newObj[curKey] = curVal;
                }
            });
        } else {
            newObj = obj;
        }

        return newObj;
    };

    return iterator;
}());