isBot(req.headers['user-agent'])

isBot('Googlebot/2.1 (+http://www.google.com/bot.html)') // true

isBot('Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36') // false

isBot('Mozilla/5.0') // false

var myList = [
    'istat',
    'newspaper',
    'httpclient',
    '^mozilla/\\d\\.\\d$',
];

isBot.extend(myList);

isBot('Mozilla/5.0') // true

isBot('Ceramic Tile Installation Guide') // true

var myList = [
	'Ceramic Tile Installation Guide',
	'NORAD National Defence Network'
];

isBot.exclude(myList);

isBot('Ceramic Tile Installation Guide') // false

isBot.exclude(['bot']);
isBot.extend(['(?<! cu)bot']); // Recognise cubot browser as legit browser

isBot('Mozilla/5.0 (Linux; Android 8.0.0; CUBOT_P20) ...') // false
isBot('Googlebot/2.1 (+http://www.google.com/bot.html)') // true

isBot.find('Googlebot/2.1 (+http://www.google.com/bot.html)') // 'bot'