How to make a field optional in reactive forms if there is a certain checkbox?

Question

Angular

Good day! There is a form with details of the organization. It must have a checkpoint field, but next to it you need to tick, they say, I am an individual entrepreneur, and the IP does not have a checkpoint. So - how to make the checkpoint field optional in reactive forms when choosing this checkbox?

Answer 1

https://stackblitz.com/edit/angular-vnskip

Answer 2

addClass you do is great - but where is removeClass?