Web Designer Constraint regular expression fail to publish when using $ in regex

Question

In the Survey123 Web Designer constraints I want my string field to only include letters, numbers, and spaces. My understanding is that the regex would be: regex(.,'^[a-zA-Z0-9 ]+$')... however this fails to publish.

I'm entering this in the UI in Web Designer

^[a-zA-Z0-9 ]+$

I've tried many many different things and it seems like the fail happens because of how $ is being handled as is passes ^[a-zA-Z0-9 ]+$ from the UI to syntax. Excluding $ does not solve the issue - it publishes but passes the constraint no matter what is entered in the string.

Publishing seems to be taking what should be regex(.,'^[a-zA-Z0-9 ]+$') and turning it into regex(.,'^[a-zA-Z0-9 ]+)) and failing to publish.

.*['"].*

works in the opposite way... like the constraint would only pass if my string includes a special character. So don't want that.

Goal:

Santa's Workshop = fail the constraint and show the message

Santas Workshop = pass the constraint and allow to submit

So how would I get this to happen if I can't use $ in the syntax without moving to survey123 connect??

KVNSCK · Answer

I know this is an older post, but I came across a similar issue. I was able to create a regular expression that allows alphanumeric characters, and spaces, but prevents special characters. It doesn't throw me an error when I save my Survey either. The advice to use a negative lookahead is what solved it for me.

^[A-Za-z0-9 ]+(?!.*[^A-Za-z0-9 ])

cjms · Answer

A work around that works for me is to use a negative lookahead (?!...) . e.g. basic phone number regex:

^\d{3}-\d{3}-\d{4}(?![\w ])

(?![\w ]) = Not followed by a-z, A-Z, 0-9, or space character.

Note: That's not a comprehensive list of all characters, just basic of what people might type in. You could add more restrictions.

Teresa_Blader · Answer

That's such a great idea BUT regular expressions right now only allow "value" and "field" is not available in the dropdown 😭