How to revert back install to a certain lower/older package version from the current latest one (real case is node and npm) ?
Help sincerely, it'd be invaluable to me, thanks before
>from the current latest one
Latest what?
Find the older versions in /var/cache/pacman/pkg.
If you can't, download them from archive.artixlinux.org or archive.archlinux.org.
even thou I don't recommend it, your best bet is to downgrade your package.
you can even keep a local mirror of old packages. some people do this in debian side.
read this
Downgrdaing packages (https://wiki.archlinux.org/title/Downgrading_packages)
downgrade to specific date (https://wiki.archlinux.org/title/Arch_Linux_Archive#How_to_restore_all_packages_to_a_specific_date)