Trigger form action when form state changes

[TechInterMezzo]

The form state system is great and I would love to have an event that gets triggered if a form state changes.
At the moment I have to poll form field values and collections in a timer loop to recreate some kind of form state watching.

It would be a lot easier if I could add a form action for form state changes.
Then I would need to read the form state. This could be a new frontend function with the state name as parameter or the state name and value could be passed as parameters to the form action.

[r3-gabriel]

I´ve had a look and unfortunately we would need to find a solution on how to bridge this state based system with timed events. Currently, if we´d react to state changes, you would get hundreds of updates as states are constantly re-evaluated on every change that might affect them.

I´ll add it to our wish list but it would not be a small feature to implement.