(Node) JS object clone

gistfile1.js

/*
    Clones an argument, intelligently.

    @param {Object} obj The object being cloned
    @returns {Object} The cloned object
*/
function objectClone(arg /*, originalObjs, newObjs */) {
    var
        originalObjs = arguments.length > 1 ? arguments[1] : [ ], // collection of original object values (used to detect where two attributes should equal the same thing)
        newObjs = arguments.length > 2 ? arguments[2] : [ ], // collection of new objects (to match up to the originals)
        result, cache, key, type;

    if ((type = typeof arg) === 'object' || arg instanceof RegExp) {
        type = Object.prototype.toString.call(arg);

        // if we found a pointer to an existing object we already passed over (or the original)
        if (type === '[object Object]' && (cache = originalObjs.indexOf(arg)) > -1) {
            return newObjs[cache];
        }

        // now the set up the result objects
        // this is done to override the objects being pointed to
        switch (type) {
            case '[object Object]':
                result = {};
                break;

            case '[object Array]':
                result = [];
                break;

            case '[object Date]':
                result = new Date(arg.getTime());
                break;

            case '[object Error]':
                result = new global[arg.name && global[arg.name] ? arg.name : 'Error'];
                break;

            case '[object RegExp]':
                cache = /\/(.*)\/(\w*)/.exec(arg.toString());
                result = new RegExp(cache[1], cache[2]);
                break;

            default:
                result = arg;
        }

        // creating a reference to both the original and new objects, as a sort of lookup
        switch (type) {
            case '[object Object]':
            case '[object Array]':
            case '[object Date]':
            case '[object Error]':
            case '[object RegExp]':
                newObjs[originalObjs.push(arg) - 1] = result;
                break;
        }
    }
    else {
        result = arg;
    }

    for (key in arg) {
        if (arg.hasOwnProperty(key) && !(type === 'string' && arg.propertyIsEnumerable(key))) {
            result[key] = objectClone(arg[key], originalObjs, newObjs);
        }
    }

    if (arguments.length < 2) {
        originalObjs = newObjs = undefined;
    }

    return result;
}

Any tips on improvements would be appreciated.

Just realized current is not used.

took out current, added Error & RegExp cloning, attempting to force garbage collection of the reference arrays when finished...