Show HN: Worry-free object traversal in JavaScript

A co-worker today challenged me to come up with a way of traversing objects in JavaScript without worrying about whether any intermediary values were undefined. It had to be short, and it had to have an elegant syntax. This is what I came up with.

I'm curious about how it could be done better, or whether people feel like it's an abomination, and a violation of the way people expect to work with objects in JavaScript.