Reset action button output in shiny

Question

I am working on a prediction model using R Shiny.

I have as input some variables for the model, like sex, age, height.... I than have a action button saying "Generate Prediction".

When pressed, some text and figures appear based on the prediction made with the input variables.

I also included a "reset" action button.

I want when this button is pressed for all variables to go to original value (that already works) AND that the output generated after the "Generate Prediction" button disappears.

My problem is with the second part of this wish.

Is it possible and how can I remove the output after pressing "reset"?

Find my script below as an example (the real script is more complex). I would like the part stating from "Results of prediction" to disappear when reset is pressed.

library(shiny)

# Define UI ----
ui <- fluidPage(
  titlePanel(title=div( "COPD risk prediction tool")),

  p("Chronic Obstructive Pulmonary Disease (COPD) is a lung problem that can affect people mainly as they get older. One of the main features of COPD is a change in the airways that alters how the air is held in the lungs and the ease with which breathing occurs (the airways become 'obstructed'). This may cause breathlessness, frequent coughing, production of sputum from your chest, and chest infections."),

  selectInput("sex", label=h4("What is your gender?"),
              choices=list("Female"=0, "Male"=1), selected=0),       
  selectInput("age", label=h4("What is your age?"),
              choices=list("18"=18, "19"=19, "20"=20, "21"=21, "22"=22, "23"=23, "24"=24, "25"=25, "26"=26, "27"=27, "28"=28, "29"=29, "30"=30), selected=20),
  bsTooltip("age",
            "What is your current age in years?","right"),
  selectInput("weight", label=h4("What is your weight?"),
              choices=list("50"=50, "51"=51, "52"=52, "53"=53, "54"=54, "55"=55, "56"=56, "57"=57, "58"=58, "59"=59, "60"=60, "61"=61, "62"=62, "63"=63, "64"=64, "65"=65, "66"=66, "67"=67, "68"=68, "69"=69, "70"=70, "71"=71, "72"=72, "73"=73, "74"=74, "75"=75, "76"=76, "77"=77, "78"=78, "79"=79, "80"=80, "81"=81, "82"=82, "83"=83, "84"=84, "85"=85, "86"=86, "87"=87, "88"=88, "89"=89, "90"=90, "91"=91, "92"=92, "93"=93, "94"=94, "95"=95, "96"=96, "97"=97, "98"=98, "99"=99, "100"=100), selected=75),
  bsTooltip("weight", 
            "What is your current weight in kg?", "right"),
  selectInput("height", label=h4("What is your height?"),
              choices=list("140"=140, "141"=141, "142"=142, "143"=143, "144"=144, "145"=145, "146"=146, "147"=147, "148"=148, "149"=149, "150"=150, "151"=151, "152"=152, "153"=153, "154"=154, "155"=155, "156"=156, "157"=157, "158"=158, "159"=159, "160"=160, "161"=161, "162"=162, "163"=163, "164"=164, "165"=165, "166"=166, "167"=167, "168"=168, "169"=169, "170"=170, "171"=171, "172"=172, "173"=173, "174"=174, "175"=175, "176"=176, "177"=177, "178"=178, "179"=179, "180"=180, "181"=181, "182"=182, "183"=183, "184"=184, "185"=185), selected=170),
  bsTooltip("height",
            "What is your current height in cm?", "right"),
  br(),

  h4("Medical Disclaimer", style = "color:blue"),
  p(strong("This risk prediction tool is for general information and should not replace advice from your GP who knows your individual history.", style = "color:blue")),
  p(strong("Although we have included major risk factors, COPD can affect anyone and if you have symptoms or concerns you should speak to your doctor.", style = "color:blue")),
  p(strong("This risk score is derived from Caucasian populations and may not be as accurate for other ethnic groups.", style = "color:blue")),

  actionButton("submit", label = "Generate Prediction"), actionButton("reset", label=("Reset")),

  h2(textOutput('title')),
  h4(textOutput('label1')),
  h5(textOutput('label2')),
  verbatimTextOutput("prediction")
)


# Define server logic ----
server <- function(input, output,session) {

  submit <- FALSE
  output$title <- eventReactive(input$submit, {
    'Results of prediction'
  })
  output$label1 <- eventReactive(input$submit, {
    'COPD risk prediction score'
  })
  output$label2 <- eventReactive(input$submit, {
    'Your predicted risk (%) of developing COPD in your lifetime is:'
  })
  output$prediction <- eventReactive(input$submit, {
  round((copdRisk(weight=input$weight, height=input$height, sex=input$sex)*100), 1)
  })

  output$label5 <- eventReactive(input$submit, {
    'This means that for every 100 people sharing your characteristics '
  })  
  output$label6 <- eventReactive(input$submit, {
    'would develop COPD in their lifetime.'
  })

    observe({
    input$reset
    updateSelectInput(session, "age", selected=20)
    updateSelectInput(session, "weight", selected=75)
    updateSelectInput(session, "height", selected=170)
    updateSelectInput(session, "sex", selected=0)
    #updateActionButton(session, "submit", selected=FALSE)
  })
}

# Run the app ----
shinyApp(ui = ui, server = server)

Answer 1

In my answer below I will demonstrate how to achieve what you're asking for. In my answer I use the shinyjs package, both for resetting input values and for hiding/showing the results. I cannot run your code because there are extra packages and functions that you are using that I don't know about, and the code itself is not a minimal isolated example, so instead I'll write my own small app that does something similar and achieves what you want. Here is the code:

library(shiny)

ui <- fluidPage(
  shinyjs::useShinyjs(),
  numericInput("num", "Enter a number", 7),
  actionButton("submit", "Square that number!"),
  actionButton("reset", "Reset"),
  shinyjs::hidden(
    div(
      id = "results",
      h3("The square is"),
      textOutput("square")
    )
  )
)

server <- function(input, output, session) {
  output$square <- renderText({
    input$submit
    isolate(input$num * input$num)
  })

  observeEvent(input$reset, {
    shinyjs::reset("num")
    shinyjs::hide("results")
  })

  observeEvent(input$submit, {
    shinyjs::show("results")
  })
}

shinyApp(ui = ui, server = server)

To address your two questions specifically and how they are solved above:

1. To reset inputs to their original value, I use the shinyjs::reset() function. This is a much better approach than updating the inputs to a particular value, because the reset() function will guarantee to reset it to whatever value it was originally, whereas your approach means that if you change the initial value in the UI, you must remember to change it in the server as well.

2. To hide the results after pressing reset, I wrapped all the results UI inside a div(id = "results", ...). Then whenever the submit button is pressed, I use shinyjs to show it, and when reset is pressed I use shinyjs to hide it. I also wrapped the UI in a shinyjs::hidden(...) because you want the results to start off as not showing.

Both of the above require a call to shinyjs::useShinyjs() in the UI.

You should be able to build off this example and implement these techniques in your more complex app.

Also note that my sample app above does a few other things differently than yours. For example, you should not use output$X <- eventReactive(...). You should use the render functions (such as renderText()) when assigning into outputs.

Answer 2

For people who have the same problem, this might also be a solution: Restart Shiny Session. In this way all inputs and output are reset, but it takes more time.