recursive deep object getter

stuff.js

var assert = require('assert');

var o = {a: {b: 'c'}, d: {e: {f: 'GG'}}};

assert.equal(get(o, 'a'), o.a);
assert.equal(get(o, 'd'), o.d);
assert.equal(get(o, 'd.e'), o.d.e);
assert.equal(get(o, 'd.e.f'), 'GG');
assert.equal(get(o, 'foobar'), undefined);
assert.equal(get(o, 'foobar.is.not'), undefined);
assert.equal(get(o, 'foobar.is.not.there'), undefined);

function get(source, key, memo) {
  memo = memo || '';
  var parts = key.split('.').reverse(),
    last = parts.length === 1,
    thing = source[parts[parts.length - 1]] || source[parts[0]] || source[memo.split('.')[0]];

  parts.pop();
  if(last) {
    // prevent deep traversal when we're on the last part of the key
    return thing;
  }

  if(thing && typeof thing === 'object' ) {
    return get(thing, parts.join('.'), key);
  }

  return thing;
}