`getSubRows()` should be lazy

[githorse]

material-react-table version

v2.1.0

react & react-dom versions

v18.2.0

Describe the bug and the steps to reproduce it

When manually defining getSubRows, I expected this function to be called as needed, dynamically, when I click expand a row in the grid. Instead, it's called up front for every level of aggregation, all the way down, on every row. That's a huge and unnecessary performance hit -- the vast majority of levels will never be expanded (in my use case, at least) and there's no need to calculate them up front.

Contrast this with, for example, AG Grid's server-side row grouping, which requests new rows as needed to expand the grid. (In my case, I'm not actually doing that expansion on the server, but calculating the rows from the raw data on the client side, along the lines of their example.)

I'm not sure if this issue is in MRT or the underlying Tanstack Table, but it makes MRT a non-starter for my large dataset. Can MRT be updated to call getSubRows dynamically to improve performance?

Note that I don't fully understand the manual grouping / aggregation feature, so I may be misunderstanding something here.

Minimal, Reproducible Example - (Optional, but Recommended)

Code Sandbox example

Screenshots or Videos (Optional)

No response

Do you intend to try to help solve this bug with your own PR?

No, because I do not know how

Terms

• [X] I understand that if my bug cannot be reliably reproduced in a debuggable environment, it will probably not be fixed and this issue may even be closed.

[KevinVandy]

Sub rows can still be lazy, but the getSubRows function itself cannot. I'll have to write more about this later when I have time.

[KevinVandy]

There is now an official lazy sub-rows example - https://www.material-react-table.com/docs/examples/lazy-sub-rows

Also some official docs discussing the main concept for how to do it: https://www.material-react-table.com/docs/guides/expanding-sub-rows#lazy-load-sub-rows