Detect Search Crawlers via JavaScript

This is the regex the ruby UA agent_orange library uses to test if a userAgent looks to be a bot. You can narrow it down for specific bots by referencing the bot userAgent list here:

/bot|crawler|spider|crawling/i

For example you have some object, util.browser, you can store what type of device a user is on:

util.browser = {
   bot: /bot|googlebot|crawler|spider|robot|crawling/i.test(navigator.userAgent),
   mobile: ...,
   desktop: ...
}