My immediate thought when I saw this was: Takes regular expressions as user input. Probably DOS'able. After looking at it for a few seconds, I realised that i

My immediate thought when I saw this was: Takes regular expressions as user input. Probably DOS'able. After looking at it for a few seconds, I realised that it's doing the regex matching on the client side, so it's ok. If you ever accept arbitrary regular expressions as user input, be very careful: https://www.owasp.org/index.php/Regular_expression_Denial_of_Service_-_ReDoS https://www.owasp.org/index.php/Regular_expression_Denial_of...