Should selection.data modify the enter and exit selections, too?

[mbostock]

Now that selection.data modifies the update selection in-place, wouldn’t it also make sense to modify the enter and exit selections in-place, too (rather than modifying the update selection in-place but creating new enter and exit selections)?

[mbostock]

One downside of modifying in-place is that bad things happen if someone modifies the number of in-place groups. But that shouldn’t happen if the groups array is private.