Optimization: Only update the model when you scroll enough to change the skipCount

[Herteby]

When scrolling, instead of updating on every scroll event/animationFrame, you could save a lot of rerenders by only doing it when it actually changes the skipCount. You can even add "chunking" so that it only updates every third row for example.

Example from my own virtual-list implementation:

 on "scroll"
    (Decode.map2
        (\scrollTop clientHeight ->
            { offset = floor scrollTop // itemHeight // chunkSize
            , containerHeight = floor clientHeight
            }
        )
        (Decode.at [ "target", "scrollTop" ] Decode.float)
        (Decode.at [ "target", "clientHeight" ] Decode.float)
        |> Decode.andThen
            (\newState ->
                if newState == state then
                    Decode.fail "No difference, ignore"
    
                else
                    Decode.succeed (onScroll newState)
            )
    )

https://gist.github.com/Herteby/ef0a9b4d688a216d9ebdc6968c9a0907

[FabienHenon]

Nice :) Would you mind creating a PR? :)