Animator.previous returns incorrect state

[absynce]

Issue
Animator.previous always shows the initial state instead of the previous state.

Expected
Animator.previous to show the previous state.

Example Ellies

• SSCCE
• Loading example does not show previous comment

Issue since version 1.0.2. It worked as expected in 1.0.1.

[matsumonkie]

Hello there!
I'm facing the same issue. I started git bisecting and it seems the culprit commit is 4461b4f that appears between 1.0.1 and 1.0.2
I can confirm 1.0.1 doesn't have this issue.

Now I don't think I can go further without investing a lot of time :-(

ps: Great lib @mdgriffith, I love it so far!

[Luftzig]

I've created a small reproduction of this bug here: https://ellie-app.com/brTmsMSBJfFa1

[Luftzig]

I've managed to create a workaround for displaying the entering and leaving items. The key components are:

        arrivedPage =
            Animator.arrived model.page
        currentPage =
            Animator.current model.page
        oldPage =
            if arrivedPage == currentPage then
                Nothing
            else
                Just arrivedPage

Hopefully I'll find the time to add to my example above as well.