Select or highlight data on map by click on legend - r

Question

Is there any way to select or highlight data on a leaflet map in by clicking on the legend in Rshiny?
example code:
library(shiny)
library(leaflet)
library(RColorBrewer)
library(leafletGeocoderRshiny)
ui <- fluidPage(
leafletOutput("map"),
p(),
actionButton("recalc", "New points")
)
server <- function(input, output, session) {
df = data.frame(x = rnorm(100), y = rexp(100, 2), z = runif(100))
pal = colorBin('PuOr', df$z, bins = c(0, .1, .4, .9, 1))
output$map <- renderLeaflet({ leaflet(df) %>%
addCircleMarkers(~x, ~y, color = ~pal(z)) %>%
addLegend(pal = pal, values = ~z)
})
}
shinyApp(ui, server)

Answer 1

The recent updates (0.2) to the mapedit package may help: http://r-spatial.org/r/2017/06/09/mapedit_0-2-0.html

Answer 2

I got close, but ran out of time now. But i decided to share anyway, maybe someone else sees a solution to the last step.
So far it works for the first click on any of the rectangles in the legend. It doesnt work for any following clicks as the map is redrawn and with it the onclick listeners are deleted. I didnt find a way to add them again so far,...
Its a hacky aprroach: I add onclick listener to the boxes and decided to update the colors via R as i didnt see a good way in JS.
library(shiny)
library(leaflet)
library(RColorBrewer)
library(leafletGeocoderRshiny)
library(shinyjs)
colors <- c("#000000", "#222222", "#888888", "#FFFFFF")
ui <- fluidPage(
useShinyjs(),
leafletOutput("map"),
p(),
actionButton("recalc", "New points")
)
server <- function(input, output, session) {
global <- reactiveValues(colors = colors,
bins = c(0, .1, .4, .9, 1))
observe({
print(input$interval)
isolate({
if(!is.null(input$interval)){
lowerBound <- as.numeric(unlist(input$interval))
global$colors <- colors
global$colors[which(global$bins == lowerBound)] <- "#FF0000"
}
})
})
session$onFlushed(function() {
runjs("
var legendButton = document.getElementsByTagName('i')
var elem; var interval;
for (nr = 0; nr < legendButton.length; nr++) {
elem = legendButton[nr]
elem.onclick = function(e){
console.log(e.target)
interval = e.target.nextSibling.nodeValue.split(' ');
Shiny.onInputChange('interval', interval[1]);
}
}
")
})
df = data.frame(x = rnorm(100), y = rexp(100, 2), z = runif(100))
pal = reactive({
colorBin(global$colors, df$z, bins = global$bins)
})
output$map <- renderLeaflet({ leaflet(df) %>%
addCircleMarkers(~x, ~y, color = ~pal()(z)) %>%
addLegend(pal = pal(), values = ~z)
})
}
runApp(shinyApp(ui, server), launch.browser = T)