Using enter key with action button in R Shiny

Question

I am trying to write a javascript function to extend the R shiny action button demo. I would like the user to be able to enter a number by both clicking the action button an

Answer 1

Here is my best solution. I don't really like it tbh, but at least it works.

library(shiny)
# This is a demo app to test a key binding on an actionButton
# Uncommenting the info item (on both UI and server) will display internal stuff
runApp( 
  list(
    #############################################
    # UI 
    #############################################
    ui = bootstrapPage(
      textInput ("myinput", label = "Write something here"),
      tags$script('
        $(document).on("keydown", function (e) {
        Shiny.onInputChange("lastkeypresscode", e.keyCode);
        });
        '),
      actionButton("GO", "Lancer le matching !"),
      # verbatimTextOutput("info"),
      verbatimTextOutput("results")
    ), 

    #############################################
    # SERVER 
    #############################################
    server = function(input, output, session) {

      # There are state variables for the input text and GO button
      curr.val <- "" # Corresponds to the current displayed input$myinput
      curr.go  <- 0  # Corresponds to the last known GO value (integer)

      lastEvent <- reactive({
        # Is reactive to the following events
        input$GO
        input$lastkeypresscode

        # Decide which action should be taken
        if(input$GO > curr.go) {
          # The user pushed the GO actionButton, so take action
          action <- 1
          curr.go <<- input$GO
        } else if(input$lastkeypresscode == 13) {
          # The user pressed the Enter key, so take action
          action <- 1
        } else {
          # The user did anything else, so do nothing
          action <- 0
        }

        return(action)
      })

      output$results = renderPrint({
        if(lastEvent() == 1) {
          curr.val <<- isolate(input$myinput)
        }
        curr.val
      })

      # output$info = renderText({
      #   paste(curr.val, curr.go, input$lastkeypresscode, sep = ", ")
      # })
    }
  )
)