I would like to have consecutive invoice numbers, but the succ method sucks (pun intended) in this case.
'427'.succ
> '428' (works!)
'2021-9'.succ
> '2022-0' (does not work)
'2021.9'.succ
> '2022.0' (does not work)
I couldn't find a gem for this, only a gem to sort strings naturally. If no one knows any existing solutions, I will answer this question with a self-programmed method shortly.
You could use String#gsub and apply succ on the matched digit:
'427'.gsub(/\D(\d+)$|^\d+$/, &:succ)
# "428"
'2021-9'.gsub(/\D(\d+)$|^\d+$/, &:succ)
# "2021-10"
'2021-624'.gsub(/\D(\d+)$|^\d+$/, &:succ)
# "2021-625"