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('.');
};

A one-liner:

const getRoot =  (url = "") => (new URL(url)).hostname.split('.').slice(-2).join('.')

@innocentamadi that also does not work depending on how many ending segments the domain has. For www.fhstp.ac.at (my school domain), it would only give you ac.at

this works -

function extractDomain(url) {
// Remove protocol if exists
let domain = url.replace(/^https?:///i, '');

// Remove www. if exists
domain = domain.replace(/^www\./i, '');

// Get the hostname from the URL
try {
    domain = new URL('http://' + domain).hostname;
} catch (error) {
    // If there's an error in URL parsing, return the original domain
    return domain;
}

// Extract subdomains
const parts = domain.split('.');
if (parts.length > 2) {
    // Check if the last part is a TLD (Top Level Domain)
    if (parts[parts.length - 1].length <= 3) {
        // Handles cases like co.uk, com.au, etc.
        domain = parts.slice(-3).join('.');
    } else {
        domain = parts.slice(-2).join('.');
    }
}

// Add www. prefix back if it exists in the original URL
if (url.includes('www.')) {
    domain = 'www.' + domain;
}

return domain;

}

// Test cases
console.log(extractDomain("https://studio.youtube.com/channel/UCntj-iDUfMBvc8_peZWbQ4g/editing/sections")); // Output: studio.youtube.com
console.log(extractDomain("https://www.youtube.com/")); // Output: www.youtube.com
console.log(extractDomain("https://www.youtube.com/channel/UCntj-iDUfMBvc8_peZWbQ4g")); // Output: www.youtube.com

thanks