Определение типа браузера в JS

var userAgent = navigator.userAgent.toLowerCase();

  let userBrowser = undefined;

  if(/firefox/.test(userAgent))
    userBrowser = "Firefox";
  else if(/chrome/.test(userAgent))
    userBrowser = "Chrome";
  else if(/safari/.test(userAgent))
    userBrowser = "Safari";
  else if(/opera/.test(userAgent))
    userBrowser = "Opera";
  else if((/mozilla/.test(userAgent) && !/firefox/.test(userAgent) && !/chrome/.test(userAgent) && !/safari/.test(userAgent) && !/opera/.test(userAgent)) || /msie/.test(userAgent))
    userBrowser = "InternetExplorer";