Reactively Updating Map to Add Markers

[codyfcook]

I have a rmap in a Shiny app. I want to be able to add markers as I select locations from a checkbox group. I have tried a few ways, including a for loop over map1$marker(...). The problem is that once I change the input the map goes blank and doesn't update.

Here is my code (this code is a later attempt where I tried to use if statements, which are obviously restrictive... same problem, anyways)

## MAP 
  output$map_lib <- renderMap({
    # make map 
    map1 = Leaflet$new()
    map1$setView(c(41.8878251,-87.6494323), 10)
    map1$tileLayer("https://cdn1.apple-mapkit.com/tp/tile?type=tile&style=0&size=1&x={x}&y={y}&z={z}&scale=1&lang=en-US&imageFormat=jpg&vendorkey=546bccd01bb595c1ae74836bf94b56735aa7f907&cacheVersion=5&v=1406167")
    map1$set(dom = 'map_lib')
    map1$set(height = 550, width = 500)
    # markers
    coord <- subset(coordinates.global, coordinates.global$branch %in% lib_sum_select())

    if(length(coord$branch)<=1){
        lat <- coord[1,2]
        long <- coord[1,3]
        name <- as.character(coord[1,1])
        map1$marker(c(lat, long), bindPopup = name)
    }

    if(length(coord$branch)<=2){
      lat <- coord[2,2]
      long <- coord[2,3]
      name <- as.character(coord[2,1])
      map1$marker(c(lat, long), bindPopup = name)
    }

    if(length(coord$branch)<=3){
      lat <- coord[3,2]
      long <- coord[3,3]
      name <- as.character(coord[3,1])
      map1$marker(c(lat, long), bindPopup = name)
    }

    # finally try the map
    map1

  })