'Reset inputs' button in shiny app

Question

I would like to implement a \'Reset inputs\' button in my shiny app.

Here is an example with just two inputs where I\'m using the update functions to set the values

Answer 1

Here is yet another option that works for either static or dynamic inputs, and doesn't involve re-rendering inputs entirely.

It uses:

reactiveValuesToList to get all initial input values, and (optionally) any dynamic input values that get initialized afterward.

session$sendInputMessage to update values for generic inputs. The updateXyzInput functions call this under the hood like session$sendInputMessage(inputId, list(value = x, ...).

Every Shiny input uses value for its input message, and almost all will update with their input value as-is. Only a two inputs I've found need special casing - checkboxGroupInput to not send NULL when nothing is checked, and dateRangeInput to convert its c(start, end) to a list(start = start, end = end).

It may not be a good idea to blindly reset ALL inputs (even tabs will be reset), but this can easily be adapted to reset a filtered set of inputs.

library(shiny)

ui <- pageWithSidebar(
  headerPanel("'Reset inputs' button example"),

  sidebarPanel(
    numericInput("mynumber", "Enter a number", 20),
    textInput("mytext", "Enter text", "test"),
    textAreaInput("mytextarea", "Enter text", "test"),
    passwordInput("mypassword", "Enter a password", "password"),
    checkboxInput("mycheckbox", "Check"),
    checkboxGroupInput("mycheckboxgroup", "Choose a number", choices = c(1, 2, 3)),
    radioButtons("myradio", "Select a number", c(1, 2, 3)),
    sliderInput("myslider", "Select a number", 1, 5, c(1,2)),
    uiOutput("myselUI"),
    uiOutput("mydateUI"),
    tags$hr(),
    actionButton("reset_input", "Reset inputs")
  ),

  mainPanel(
    h4("Summary"),
    verbatimTextOutput("summary")
  )
)

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

  initialInputs <- isolate(reactiveValuesToList(input))

  observe({
    # OPTIONAL - save initial values of dynamic inputs
    inputValues <- reactiveValuesToList(input)
    initialInputs <<- utils::modifyList(inputValues, initialInputs)
  })

  observeEvent(input$reset_input, {
    for (id in names(initialInputs)) {
      value <- initialInputs[[id]]
      # For empty checkboxGroupInputs
      if (is.null(value)) value <- ""
      session$sendInputMessage(id, list(value = value))
    }
  })

  output$myselUI <- renderUI({
    selectInput("mysel", "Select a number", c(1, 2, 3))
  })

  output$mydateUI <- renderUI({
    dateInput("mydate", "Enter a date")
  })

  output$summary <- renderText({
    return(paste(input$mytext, input$mynumber))
  })
}

shinyApp(ui, server)