R Auto Zoom Updated leafletProxy Map object in Shiny

Question

I am experimenting with the leaflet package for some maps in Shiny. I would like to be able to have a base map that data will change and subsequently be remapped. However, I am trying to use the leafletProxy function whereby there is a base map and I just change the data points that are added. All of this works however the map doesn't zoom to the datapoints location. It remains at the farthest zoom.

The code to reproduce the problem:

library(shiny)
library(leaflet)

r_colors <- rgb(t(col2rgb(colors()) / 255))
names(r_colors) <- colors()

ui <- fluidPage(
  leafletOutput("mymap"),
  p(),
  actionButton("goButton", "New Points")
)

server <- function(input, output, session) {

  output$mymap <- renderLeaflet({
    leaflet() %>%
      addProviderTiles("Stamen.TonerLite",
                       options = providerTileOptions(noWrap = TRUE)
      )
  })

  observeEvent(input$goButton, {
    points <- cbind(rnorm(40) * 2 + 13, rnorm(40) + 48)

    leafletProxy('mymap', session) %>%
      clearMarkers() %>%
      addMarkers(data = points)
  })
}

shinyApp(ui, server)

I would like the map to automatically zoom in once new points have been added.

Answer 1

try to add argument "fitBounds" in leafletProxy()

leafletProxy('mymap', session) %>%
  clearMarkers() %>%
  addMarkers(data = points) %>%
  fitBounds(lng1 = max(points$long),lat1 = max(points$lat),
            lng2 = min(points$long),lat2 = min(points$lat))

Answer 2

I revised G. Cocca's answer (mostly by adding a dataframe of "points") to get this:

library(shiny)
library(leaflet)

r_colors <- rgb(t(col2rgb(colors()) / 255))
names(r_colors) <- colors()

ui <- fluidPage(
  leafletOutput("mymap"),
  p(),
  actionButton("goButton", "New Points")
)

server <- function(input, output, session) {

  output$mymap <- renderLeaflet({
    leaflet() %>%
      addProviderTiles("Stamen.TonerLite",
                       options = providerTileOptions(noWrap = TRUE)
      )
  })

  observeEvent(input$goButton, {
    points <- data.frame("long" = rnorm(40) * 2 + 13, 
                            "lat" = rnorm(40) + 48)


    leafletProxy('mymap', session) %>%
      clearMarkers() %>%
      addMarkers(data = points) %>%
      fitBounds(lng1 = max(points$long),lat1 = max(points$lat),
                lng2 = min(points$long),lat2 = min(points$lat))


  })
}

shinyApp(ui, server)