I believe that the first condition in an conditional should be the most often case or the expected result, where `else` and `elsif` handle the outliers. In this case, the outlier is when the last version of the list and there should be no comma at the end. All of the preceding versions do have commas.

I would prefer the `unless` be the first part or have it changed to a `if !` instead of changing the ordering of the condition. While it is not a big deal, it is intention revealing when reading through conditionals in the view.