Typescript grammar in Bison

Hi friends!

I've been a Bison user for some time now, I've been writing some toy
projects here and there. I was wondering if there are online resources I
could find existing grammar from well-known programming languages? Just the
definitions, not the implementations of course.

More specifically, I'm looking for an existing Typescript grammar I could
use for a personal project. I guess Javascript would work too. I've looked
online and haven't had any luck so far.



Thanks in advance,
Ricard