Converting an empty string into nil in Ruby

Question

I have a string called word and a function called infinitive such that
word.infinitive would return another string on some occasions and an empty string otherwise
I am trying to find an elegant ruby one line expression for the code-snippet below

if word.infinitive == ""       return word else return word.infinitive 

Had infinitive returned nil instead of "", I could have done something like

(word.infinitive or word) 

But since it does not, I can't take advantage of the short-circuit OR
Ideally I would want
1) a single expression that I could easily embed in other code
2) the function infinitive being called only once
3) to not add any custom gems or plugins into my code

Answer 1

The ActiveSupport presence method converts an empty (or blank?) string to nil. It's designed for your exact use case:

word.infinitive.presence || word 

Note that you can easily use ActiveSupport outside of rails:

require 'active_support/core_ext/object/blank'