The `&&` or `||` stuff for a default is really an anti-pattern from JavaScript. It leads to problems with truthy or falsy defaulting. What you really want is a [null coalescing operator][1]. However, in this case, you're indexing into a map, so you can use [fetch][2].

[1]: http://en.wikipedia.org/wiki/Null_coalescing_operator
[2]: http://www.ruby-doc.org/core-1.9.3/Hash.html#method-i-fetch