Редакция для IPv4
let isIpv4Valid = ipStr.match('/^((25[0-5]|2[0-4][0-9]|[10]?[0-9]?[0-9])(\.|$)){4}/ig')
Energetic Echidna
let isIpv4Valid = ipStr.match('/^((25[0-5]|2[0-4][0-9]|[10]?[0-9]?[0-9])(\.|$)){4}/ig')
let isIpv4Valid = ipStr.match('/\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}\b/ig')