code: function getTld( domainName ) {
  	const lastIndexOfDot = domainName.lastIndexOf( '.' );
  
  	if ( lastIndexOfDot === -1 ) {
  		return '';
  	}
  
  	let tld = parseDomainAgainstTldList( domainName, wpcomMultiLevelTlds );
  
  	if ( ! tld ) {
  		tld = domainName.substring( lastIndexOfDot + 1 );
  	}
  
  	return tld;
  }
docs: Parse the tld from a given domain name, semi-naively. The function
  first parses against a list of tlds that have been sold on WP.com
  and falls back to a simplistic "everything after the last dot" approach
  if the whitelist failed. This is ultimately not comprehensive as that
  is a poor base assumption (lots of second level tlds, etc). However,
  for our purposes, the approach should be "good enough" for a long time.
  
  @param {string}     domainName     The domain name parse the tld from
  @return {string}                   The TLD or an empty string