addLegend group not working when group is in addLayersControl baseGroups

[wimpel]

In my shiny-app, i've got a leaflet, based on reactive userinput

  output$leafletMap2 <- renderLeaflet({
    leaflet(df[which(!is.na(df$latitude)), ]) %>% addTiles() %>% setView(4.213, 51.876, zoom = 7)
  })

  observe({
    leafletProxy("leafletMap2", data = filteredData() ) %>% 
      clearGroup("test1") %>%
      clearGroup("test2") %>%
      clearGroup("test3") %>%
      addCircleMarkers(lng = ~longitude,
                       lat = ~latitude,
                       radius = 6,
                       color = ~pal(process),
                       stroke = FALSE,
                       fillOpacity = 1,
                       popup = paste(filteredData()$time, "<br>", filteredData()$description),
                       popupOptions = popupOptions(closeOnClick = FALSE),
                       group = "test1") %>%
      addCircleMarkers(lng = ~longitude,
                       lat = ~latitude,
                       radius = 6,                        
                       color = ~pal(PROCES),
                       stroke = FALSE,
                       fillOpacity = 1,
                       clusterOptions = markerClusterOptions() ,
                       popup = paste(filteredData()$time, "<br>", filteredData()$description),
                       popupOptions = popupOptions(closeOnClick = FALSE),
                       group = "test2") %>%
      addHeatmap(lng = ~longitude,
                 lat = ~latitude,
                 blur = 15,                 
                 max = 1, 
                 radius = 10,              
                 intensity = 0.25,       
                 group = "test3") %>%
      clearControls() %>%
      addLegend(position = "bottomleft",
                pal = pal,
                values = sort( unique(filteredData()$PROCES) ),
                opacity = 1,
                group = "test1") %>%
      addLayersControl(baseGroups = c("test3", "test1", "test2"), 
                       #overlayGroups = c("test3", "test1", "test2"), 
                       options = layersControlOptions(collapsed = FALSE)
      )
  })

I would like the legend to show only when test3 is the selected layer. This does not work when I select a layer from the baseGroups (with radiobuttons). However, it does work when I add the laters to the overlayGroups (with checkboxes). I rather do not want to do that, because I want the user not to be able to select multiple layers at once).

Not sure if this is a bug-report, feature request or that I'm simply missing somthing ;-).

[bhaskarvk]

Yeah I haven't added support for baselayer change. I think I can add it though.

[wimpel]

That would be great! I wpould be happy to test :)

[ummel]

I, too, would make use of this functionality (i.e. baseGroups correctly toggling legends). Here is a snippet based on ?addLegend example that produces the issue:

df = local({
  n = 300; x = rnorm(n); y = rnorm(n)
  z = sqrt(x^2 + y^2); z[sample(n, 10)] = NA
  z2 <- z ^ 2
  data.frame(x, y, z, z2)
})

pal1 = colorNumeric('OrRd', df$z)
pal2 = colorNumeric('OrRd', df$z2)

leaflet(df) %>%
  addTiles() %>%
  addCircleMarkers(~x, ~y, color = ~pal1(z), group='circles1') %>%
  addCircleMarkers(~x, ~y, color = ~pal2(z2), group='circles2') %>%
  addLegend(pal = pal1, values = ~z, group='circles1', position='bottomleft') %>%
  addLegend(pal = pal2, values = ~z2, group='circles2', position='bottomleft') %>%
  addLayersControl(baseGroups = c('circles1', 'circles2'))

[mmari]

I aggree that add "group" option inside "addLegend" would be great!!

[wimpel]

@bhaskarvk
Could you indicate if, and if so: when, this feature will be added?

[bantaj]

+1. I would use this feature quite often.

[bhaskarvk]

This is not as straightforward to implement as overlay groups. The reason being that when an overlay group swaps we get JS events for both groups, the one that is going out and the one that is coming in, and we get the group name in the event. This makes it easy to tie the legend to every overlay gorup's add/remove events.
Unfortunately for base group we receive group name in the JS event only for the group that is coming in. This means there's is no way to know which group was on the way out.
There is a roundabout way of achieving this, but I don't have the time right now to work on this. Unless @jcheng5 has some free cycles, I don't see this getting resolved anytime soon.

[jcheng5]

@schloerke Maybe you can at least scope this, even if we don't include it in 1.2.0?

[beansrowning]

@jcheng5 is it still anticipated that this will be in the 1.2.0 release, or will it take longer to scope out?

[jcheng5]

I'll leave it to @schloerke but I don't think it will, the 1.2.0 release has already taken much longer than we realized it would due to tasks that absolutely have to be done (bringing leaflet.extras and leaflet.esri packages up to date, for example--I was under the mistaken impression that was done already).

[beansrowning]

Thanks for the update. Definitely understandable that those updates take precedence.

[schloerke]

@beansrowning Sorry, I didn't get to this one this round, but I'll add it for next release

[beansrowning]

@schloerke No problem, let me know if there is something I can do to help.