handy regex - remove subdomain from full url (not perfect)

remove_subdomain.js

/**
 * Returns a url without the subdomain. If no subdomain exists, just returns the same url
 * @param {string} fullUrl - Example:  https://sub.domain.com
 * @returns {string} - Url without subdomain - Example: https://domain.com
 */
export const removeSubdomainFrom = function(fullUrl = '') {
  // configure host strings
  const regex = {
    protocol: new RegExp(/http(s)*:\/\//),          // gets the http:// OR https:// from url string
    subdomain: new RegExp(/^[^.]*\.(?=\w+\.\w+$)/)  // gets the http(s)://subdomain portion from url string
  }
  let newUrl = fullUrl
  let protocol = regex.protocol.exec(fullUrl)       // save protocol from provided Url so we can reapply it to the non-subdomain
  if (protocol && protocol.length) {
    // if https://subdomain exists, just remove the subdomain from it
    newUrl = fullUrl.replace(regex.subdomain, protocol[0])
  }
  return newUrl
}