Out of interest, is `?` preferred here (in place of `or`)? It more accurately conveys our intent: we're interested in whether `error.code` has a meaningful value, rather than whether the value is logical true.

There are rare occasions where this distinction is significant. Imagine, for example, we have an object, `model`, which may not yet exist on the server. We could write the following code:

```coffeescript
model.save() unless model.id
```

What if, though, our ids are sequential integers starting at zero. This would fail in one case. Instead, we should write:

```coffeescript
model.save() unless model.id?
```