My regex works in browser but shows an error in react-native expo app (android) development
Regex:
/^(?=.{0,20}$)(?![_.0-9])(?!.*[_.]{2})[a-zA-Z0-9._]+(?<![_.])$/
error:
Invalid regular expression: invalid group specifier name
no stack
How to fix this error, thanks
I suggest converting the (?<![_.]) lookbehind into a (?!.*[_.]$) lookahead and tighten it a bit (since the length can be checked with the consuming pattern part):
/^(?!.*[_.]$)(?![_.0-9])(?!.*[_.]{2})[a-zA-Z0-9._]{0,20}$/
Details
^ - start of string(?!.*[_.]$) - no . or _ allowed at the end(?![_.0-9]) - no _, . and digit allowed at the start(?!.*[_.]{2}) - no consecutive . or _ allowed anywhere[a-zA-Z0-9._]{0,20} - 0 to 20 letters, digits, . or _$ - end of string.
(?<![_.]). Add(?!.*[_.]$)after^. Or,/^(?!.*[_.]$)(?![_.0-9])(?!.*[_.]{2})[a-zA-Z0-9._]{0,20}$/