Prevent widows in Ruby with this simple function. It replaces only the last space character with a non-breaking space in a string.

prevent_widows.rb

def prevent_widows(text)
  if text.kind_of? String
    trimmed_text = text.rstrip
    last_space_index = trimmed_text.rindex(" ")
    
    if !last_space_index.nil?
      text[last_space_index] = " "
    end
  end

  text
end

I guess it would be more appropriately called "prevent orphans", since it's concerned with the last word not being on a line by itself.