I'm using ng-pattern on a text field to validate a Canadian phone number:

^(?([0-9]{3}))?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$

But AngularJS throws this error:

Syntax Error: Token '?' not a primary expression at column 3 of the expression [^(?([0-9]{3}))?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$] starting at [?([0-9]{3}))?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$].

I tested it, and tried it in a couple different online regex editors like Rubular, and it seems perfectly valid. I am creating the fields dynamically so ng-pattern is being set like this in the directive within ngRepeat.

ng-pattern={{field.format}}

if I change it to hardcoded regex it doesn't throw any errors:

ng-pattern=/^(?([0-9]{3}))?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$/

But then I changed it to something ridiculously simple:

^[0-9]{3}$

And this works, so can't be dynamically created fields and related to just the regex.