I like pure FP languages for writing UIs. In particular I like languages where you can't have any undefined behavior. I like modeling the state of a page/form/c

I like pure FP languages for writing UIs. In particular I like languages where you can't have any undefined behavior. I like modeling the state of a page/form/component/whatever as a bunch of constructors on a custom type, each containing exactly the data you need to render the page/form/component/whatever in that given state. I guess this isn't so specific to UIs but it's where I have the most experience. Modeling something as a state machine is cool and good.