How to determine if we are tailing at the moment?

[gajus]

There is the followOutput – however, how do I tell if we are currently tailing or not?

[petyosi]

atBottomStateChange.

[gajus]

atBottomStateChange didn't work for my use case (since I needed to check if we are at the bottom now outside of the callback), but this worked:

const [visibleRange, setVisibleRange] = useState({
  endIndex: 0,
  startIndex: 0,
});

console.log(filteredMessages.length === visibleRange.endIndex + 1);

<Virtuoso
  data={filteredMessages}
  followOutput
  rangeChanged={setVisibleRange}
/>

[gajus]

Digging deeper this made me realize that the way we were using Virtuoso was not memoized properly, i.e. followOutput was not even working as intended.

Removing data in favor of itemContent={itemContent} and totalCount={filteredMessageCount} removed the need for needing to know if we are following output because whatever we set followOutput to accurately reflects if we are following or not.