Is prepending items available in GroupedVirtuoso?

https://virtuoso.dev/prepend-items/

We are trying to implement this example wile using GroupedVirtuoso and we get this error as soon as we start using the firstItemIndex property.

also wondering if we got this right:

firstItemIndex = total of items to be loaded - the one we have loaded

In our case we are grouping by date so total of items to be loaded is difficult if not impossible to calculate as we will need to take account for the header?

thanks a lot for the great work ❤️ and I will gladly contribute again if needed 😃

[petyosi]

I think you might achieve that by re-mounting the component (by passing a different key prop) and passing different groupCounts and initialTopMostItemIndex. Not an optimal solution, even if it works.

[jonathaneckman]

I could use this as well. I tried to add the feature myself but I couldn’t get there. The only thing I was able to shake out of the experiment that may be of value is an e2e example showing:

• a list of “events” grouped by day
• initial load shows current day at the top
• infinite scroll into the future (append)
• TODO: infinite scroll into the past (prepend)

Its in my fork if you need it. Front end is not my specialty so sorry for the ugly code.