Regex to get subdomain

regexSubdomain

const url = "painel.toloja.com.br";
const regex = url.match(/[a-z]+\.?(([a-z]+)\.(([a-z]+)\.[a-z]+\.[a-z]+))[:\d]*/);
const mainUrl = regex ? (regex[2]=== "dev" ? regex[1]: regex[3]) : "defaultOrganizationUrl";
const newOrganization = regex ? regex[4] : "defaultOrganization";
console.log(regex);
console.log(mainUrl);
console.log(newOrganization);

regexSubdomain2

const url = "painel.dev.toloja.com.br";
const regex = url.match(
    /(.*)+\.([a-z]+)?\.?(([a-z]+)\.(([a-z]+)))[:\d]*/
)
let newOrganization = 'demo-ria-admin'
if (regex && regex?.length >= 5) {
    newOrganization = regex[1].includes('.')
        ? regex[1].split('.')[0]
        : regex[1]
}
console.log(regex);
console.log(newOrganization);