Add first/last as one of the built-in aggregate functions for colDef #387

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1. glin

   added

   enhancementNew feature or requestNew feature or request

   on Aug 5, 2024
2. glin commented on Aug 5, 2024

   

   glin

   on Aug 5, 2024

   Owner

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   Sure, that seems reasonable. In JS, it would also be relatively straightforward to implement, so a custom aggregate function solution could look like this:

   data <- MASS::Cars93[14:38, c("Type", "Price", "MPG.city", "DriveTrain", "Man.trans.avail")]
   
   agg_first <- JS("values => values[0]")
   agg_last <- JS("values => values[values.length - 1]")
   
   reactable(
     data,
     groupBy = "Type",
     columns = list(
       Price = colDef(aggregate = agg_first),
       DriveTrain = colDef(aggregate = agg_last)
     )
   )

   But also just to clarify, these would return the first and last elements of the group before sorting, so sorting won't change the results. If you did need the first and last elements after sorting, that'd be more difficult as grouping/aggregation is currently done before sorting. I'm not sure how feasible it would be to enable a sorting-aware aggregation.
3. C92Anderson commented on Aug 6, 2024

   

   C92Anderson

   on Aug 6, 2024 via email

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   Excellent, thank you on both fronts!

   …

   On Sun, Aug 4, 2024 at 11:33 PM Greg Lin ***@***.***> wrote: Sure, that seems reasonable. In JS, it would also be relatively straightforward to implement, so a custom aggregate function solution could look like this: data <- MASS::Cars93[14:38, c("Type", "Price", "MPG.city", "DriveTrain", "Man.trans.avail")] agg_first <- JS("values => values[0]")agg_last <- JS("values => values[values.length - 1]") reactable( data, groupBy = "Type", columns = list( Price = colDef(aggregate = agg_first), DriveTrain = colDef(aggregate = agg_last) ) ) But also just to clarify, these would return the first and last elements of the group *before* sorting, so sorting won't change the results. If you did need the first and last elements after sorting, that'd be more difficult as grouping/aggregation is currently done before sorting. I'm not sure how feasible it would be to enable a sorting-aware aggregation. — Reply to this email directly, view it on GitHub <#387 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACAO5NUQ677WOHGQNIG6TCDZP3XB3AVCNFSM6AAAAABL2X4LVWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDENRYGEYDMMJVGQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>