Add median as one of the built-in aggregate functions for colDef

[mattwarkentin]

Hi @glin,

Wondering if it would be possible to add median() as a built-in aggregate function for colDef()? I know that the user can provide a custom JS() function to do this on their own, so I could probably dig up enough JS to get it working, but I think median would be nice to have as a built-in.

Actually, while I'm thinking of it, it would be nice to be able to pass R functions instead of/in addition to JS functions, if possible. That way one could pass the median function, or an anonymous function with some other aggregating capability. Thoughts?

[glin]

Hi,

Thanks for the suggestion. Calculating the median is pretty straightforward, so I went ahead and added a "median" aggregate function in 86adb96. For example:

reactable(
  iris,
  groupBy = "Species",
  columns = list(Sepal.Length = colDef(aggregate = "median"))
)

Passing R functions would be really cool, and totally possible I think. There'd be limitations though. JS aggregate functions run on the fly and update with table changes. For example, the aggregated values update when you filter this table: https://glin.github.io/reactable/articles/examples.html#aggregated-cell-rendering. R aggregated values would have to be precalculated and never change. But it's pretty much the same trade-off as JS vs. R render functions - much easier to write custom aggregators as an R programmer. Thanks for that suggestion as well! I've added it to my to-do list, but feel free to file a separate issue for it.

[mattwarkentin]

Wow, thanks for the quick addition of the median!

Ahh yes, I did not think about how the JS functions update the table when it is modified. Well, perhaps an R function could still be passed with the knowledge that it cannot be dynamically updated once rendered. As you mention, this is just the standard expectation for any R vs. JS render functions. I can definitely think of some cool custom aggregators that I can write in R and wouldn't really know how to do in JS, only due to my own JS limitations.

Anyway, thanks for considering this! I will file its own issue.