js判断域名是否有效

function isValidDomain(domain) {
  const domainRegex = /^(?:[a-zA-Z0-9]+(?:-[a-zA-Z0-9]+)*\.)+[a-zA-Z]{2,}$/;
  return domainRegex.test(domain);
}

console.log(isValidDomain('example.com')); // true
console.log(isValidDomain('example')); // false

const dns = require('dns');

function checkDomain(domain, callback) {
  dns.resolve(domain, (err, addresses) => {
    if (err) {
      console.error(`Domain ${domain} is not valid:`, err);
      callback(false);
    } else {
      console.log(`Domain ${domain} resolved to:`, addresses);
      callback(true);
    }
  });
}

checkDomain('example.com', (isValid) => {
  console.log('Is valid domain:', isValid);
});