How to tell if isScrolling was triggered by followOutput or user scroll?

[gajus]

I want to implement behaviour that sets followOutput to false if user takes over scrolling.

One way to do this is to capture scrollerRef and inside of the isScrolling check if scroll is at the bottom, e.g.

scrollerElement.scrollHeight - scrollerElement.scrollTop - scrollerElement.clientHeight

However, this will occasionally produce a false-positive.

[petyosi]

I feel like you're doing something either very exotic or your setup is something which I haven't seen. The behavior you describe is by default for followOutput (if I understand you right). See this demo.

[gajus]

Interesting. In my case it just sticks to bottom.

followOutput is set to:

const followOutput = useCallback(() => {
  return followingOutput ? 'auto' : false;
}, [followingOutput]);

[petyosi]

Check the docs on followOutput. The callback receives an argument.

[gajus]

Awesome. My use case is addressed with:

const followOutput = useCallback((isAtBottom) => {
  if (followingOutput && !isAtBottom) {
    setFollowingOutput(false);

    return false;
  }

  return followingOutput ? 'auto' : false;
}, [
  followingOutput,
  setFollowingOutput,
]);

Thank you!