odd. here's the compilation shown in the coffeescript overview which made me think of this

![image](https://f.cloud.github.com/assets/1418690/1700547/5e4b68c4-6020-11e3-8bb6-442101cee9b5.png)

![image](https://f.cloud.github.com/assets/1418690/1700548/639c1710-6020-11e3-8e55-ae92881ef464.png)

i'm not quite sure why a more restrictive conditional would result in an error. currently, it should only disallow `@mostRecentNode` if it isn't undefined. if you used `@mostRecentNode?` it should disallow it if it is undefined or null. what kind of error are you getting?

in terms of making expectations of `nodeHash` clear to the user, I'm not sure I agree that being able to handle a `null` node should be part of it. currently, this implementation would require that of a user. `@mostRecentNodes?` would not.

regardless of which, it should be clear in the spec. oh wait, i guess I should actually write a full spec first...