getIPDomain.js

const IPV4Reg = '((([0-9])|(1*[0-9][0-9])|(2[1-4][0-9])|(25[0-5]))\\.){3}(([0-9])|(1*[0-9][0-9])|(2[1-4][0-9])|(25[0-5]))';
const IP4 = `(^${IPV4Reg}$)|(^${IPV4Reg}\\:)|(^${IPV4Reg}\/)`;

function getIPDomain(url) {
    const matches = new RegExp(IP4).exec(url);
    if (matches && matches[0]) {
        return matches[0].replace(/\:|\//, '');
    }
}