library(shiny)
library(leaflet)

view <- fluidPage(
  h1("quakes"),
  leafletOutput("map")
)

controller <- function(input, output){
  output$map <- renderLeaflet({
    leaflet() %>% addTiles() %>% addMarkers(
      data = quakes, clusterOptions = markerClusterOptions()
    )
  })
}

shinyApp(view, controller)