How to get the zoom level from the leaflet map in R/shiny?

Question

I create a map using leaflet package in Shiny which have a selectInput to allow user to select from a site list. The site list also adds into leaflet as markers

Answer 1

You can access the zoom level using input$mapid_zoom (see here).

In your observe, you could do:

 observe({
                sel_site <- df[df$site == input$site,]
                isolate({
                        new_zoom <- 4
                        if(!is.null(input$map_zoom)) new_zoom <- input$map_zoom
                        leafletProxy('map') %>%
                                setView(lng = sel_site$lng, lat = sel_site$lat, zoom = new_zoom)
                })
        })