Invalid regular expression: /^+?d{10,12}$/: Nothing to repeat in Angular Validator

I have this regexp

Validators.pattern("^[0-9]{10,15}$");

which is working

i want to give optional + sign before digits for that i tried to use

Validators.pattern("^+?d{10,12}$");

getting this error :

Invalid regular expression: /^+?d{10,12}$/: Nothing to repeat