Gist with an example demonstrating the usefulness of debouncing and throttling of a reactive expression in Shiny

shiny_debounce_throttle_demo.R

library(shiny)
library(magrittr)

counts <-
  reactiveValues(baseline = 0,
                 debounce = 0,
                 throttle = 0)

ui <- fluidPage(
  titlePanel("Slowing down a chatty reactive expression 💬🦥 - demo"),
  br(),
  fluidRow(
    column(5, 
           sliderInput('slider_baseline', 'Without debounce/throttle', min = 1, max = 10, value = 1)),
    column(4, 
           textOutput('baseline_example')),
    column(3, 
           textOutput('baseline_example_count'))
  ),
  fluidRow(
    column(5, 
           sliderInput('slider_debounce', 'With debounce', min = 1, max = 10, value = 1)),
    column(4, 
           textOutput('debounce_example')),
    column(3, 
           textOutput('debounce_example_count'))
  ),
  fluidRow(
    column(5, 
           sliderInput('slider_throttle', 'With throttle', min = 1, max = 10, value = 1)),
    column(4, 
           textOutput('throttle_example')),
    column(3, 
           textOutput('throttle_example_count'))
  )
)

server <- function(input, output, session) {
  
  
  ## Baseline example
  baseline <- reactive({
    input$slider_baseline
  })
  
  observeEvent(baseline(), {
    
    invalidated_value <- baseline()
    
    counts$baseline <- counts$baseline + 1
    
    output$baseline_example <- renderText(paste0('Invalidated at ', Sys.time(), ' with value ', invalidated_value))
    
    output$baseline_example_count <- renderText(paste0('Times invalidated: ', counts$baseline))
    
  })
  
  # Debounce example
  debounce_example <- reactive({
    input$slider_debounce
  }) 
  
  debounce_example_d <- debounce_example %>% debounce(millis = 2000)
  
  observeEvent(debounce_example_d(), {
    
    invalidated_value <- debounce_example_d()
    
    counts$debounce <- counts$debounce + 1
    
    output$debounce_example <- renderText(paste0('Invalidated at ', Sys.time(), ' with value ', invalidated_value))
    
    output$debounce_example_count <- renderText(paste0('Times invalidated: ', counts$debounce))
    
  })
  
  # Throttle example
  throttle_example <- reactive({
    input$slider_throttle
  }) 
  
  throttle_example_d <- throttle_example %>% throttle(millis = 2000)
  
  observeEvent(throttle_example_d(), {
    
    invalidated_value <- throttle_example_d()
    
    counts$throttle <- counts$throttle + 1
    
    output$throttle_example <- renderText(paste0('Invalidated at ', Sys.time(), ' with value ', invalidated_value))
    
    output$throttle_example_count <- renderText(paste0('Times invalidated: ', counts$throttle))
    
  })
  
}

shinyApp(ui = ui, server = server)