How to add a state-based check?

Question

Vue.js

Hello everyone, I use vuelidate for form validation, I ran into a problem that validation is not dynamically hung based on an additional state field in the object (this state changes true / false depending on whether the field is empty or not).
Now the form is always valid, maybe someone came across, I will be grateful

Sandbox example

Answer 1

https://codesandbox.io/s/trusting-lewin-ub3tz?file...
https://vuelidate.js.org/#sub-validation-groups