> Is every frame in a transition also a function of state? The start and end state are functions of state. The animation itself is what the element itself does

> Is every frame in a transition also a function of state? The start and end state are functions of state. The animation itself is what the element itself does when it's in the process of changing (like kicking a rock down a hill). The scroll position of some text is like this as well, it's internal state that you typically don't need to reify as application state. You could make these part of the state where necessary, but it often isn't.