Currently host validator does not accept :: as a valid IPv6 address.

There are three ways this can be solved:

1. Adjust the regexp to match ::
2. Handle :: as a special case outside of current regexp
3. Use node:net.isIPv6("::") (along with isIPv4 or isIP in general)

I see that this project has no imports from node's standard library. If this is by design, then 3. is out.