JavaScript Dictionary

dictionary.js

Dictionary = (function(){
    // http://github.com/adufilie
    function Dictionary() {
        this.set = set;
        this.get = get;
        Object.defineProperty(
            this,
            "primitives",
            {
                configurable: false,
                writable: false,
                enumerable: false,
                value: {}
            }
        );
    };

    var hiddenKey = "\x00Dictionary\x00";
    var nextId = 1;

    function getHiddenKey(key)
    {
        if (!key || typeof key != 'object')
            return 0;

        var hKey = key[hiddenKey];
        if (!hKey)
        {
            Object.defineProperty(
                key,
                hiddenKey,
                {
                    configurable: false,
                    writable: false,
                    enumerable: false,
                    value: nextId++
                }
            );
            hKey = key[hiddenKey];
        }
        return hKey;
    }

    function set(key, value)
    {
        var hKey = getHiddenKey(key);
        if (hKey == 0)
            this.primitives[key] = value;
        else
            this[hKey] = value;
    }

    function get(key)
    {
        var hKey = getHiddenKey(key);
        if (hKey == 0)
            return this.primitives[key];
        else
            return this[hKey];
    }

    return Dictionary;
})();