Dynamically controlling components at run time?

I want to programmatically open/close modals, etc. when a user clicks a button and other events.

The way it is now you can bind a button to a small set of pre-defined functions, one being opening a modal..

I want to perform some logic and then show the modal or hide it, etc.. from a runnable.

I've perused the docs to no avail and could use some tips.

Thanks!!