正则表达式验证域名

const domainRegex = /^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,6}(?:\.[a-zA-Z]{2})?$/;

const punycode = require('punycode');

function validateIDN(domain) {
    const encodedDomain = punycode.toASCII(domain);
    return domainRegex.test(encodedDomain);
}

const subdomainRegex = /^([a-zA-Z0-9]+(-[a-zA-Z0-9]+)*\.)+[a-zA-Z]{2,6}$/;

const domainRegex = /^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,6}(?:\.[a-zA-Z]{2})?$/;

function validateDomain(domain) {
    return domainRegex.test(domain);
}

// 测试
console.log(validateDomain("example.com")); // true
console.log(validateDomain("www.example.com")); // true
console.log(validateDomain("example")); // false