hydrate a javascript object from a string

gistfile1.js

// this is a quick function that may be useful to someone aside from myself. 'Hydrate' might not be the best choice
// of words, but it comes close. This takes a '.' delimited string (and optionally an existing object) and builds
// the javascript object it represents. It was originally declared inside a IIFE where U was an unused property and
// therefore guaranteed to be undefined, so I've wrapped it in one here, too.

(function (G, U) {
function hydrateObject (obj, prop) { // obj is optional
    var levels, len, ret;
    if (prop === U && typeof obj == 'string') {
        prop = obj;
        obj = {};
    }
    levels = prop.split('.').reverse();
    len = levels.length;
    ret = obj;
    while (len--)
        obj = obj[levels[len]] || (obj[levels[len]] = {});
    return ret;
}
// ... other stuff happened here
}(this));