Extract the domain name from url string

extractDomainFromUrl.js

const extractHostname = (url) => {
  let hostname = '';
  // find & remove protocol (http, ftp, etc.) and get hostname

  if (url.indexOf('//') > -1) hostname = url.split('/')[2];
  else hostname = url.split('/')[0];

  // find & remove port number
  hostname = hostname.split(':')[0];
  // find & remove "?"
  hostname = hostname.split('?')[0];

  return hostname;
} 

const extractRootDomain = (url) => {
  let domain = extractHostname(url);
  const splitArr = domain.split('.');
  const arrLen = splitArr.length;

  if (arrLen > 2) {
    domain = `${splitArr[arrLen - 2]}.${splitArr[arrLen - 1]}`;
    // check to see if it's using a Country Code Top Level Domain (ccTLD) (i.e. ".me.uk")
    if (splitArr[arrLen - 2].length === 2 && splitArr[arrLen - 1].length === 2) {
      // this is using a ccTLD
      domain = `${splitArr[arrLen - 3]}.${domain}`;
    }
  }
  return domain;
};

// string = "http://www.blog.classroom.me.uk/index.php"
// console.warn(extractHostname(string));
// Output: www.blog.classroom.me.uk
// console.warn(extractRootDomain(string));
// Output: classroom.me.uk