Problem with combination of hide(), show() and reset() in shiny-CodePudding

I have been having problems combining the hide(), show() and reset() functions from the shinyjs package. I have two divs. One div collects data using multiple user inputs and ends with a submit button. Once the submit button is pressed, another div should appear that shows the collected data in a table. In this second div, there is another button that should reset the original giv and show it again so that more data can be collected.

I tried to produce a reproducible example using some code from the shinyjs help page:

library(shiny)
library(shinyjs)

shinyApp(
 ui = fluidPage(
   useShinyjs(),
   div(
     id = "form",
     textInput("name", "Name", "Dean"),
     radioButtons("gender", "Gender", c("Male", "Female")),
     selectInput("letter", "Favourite letter", LETTERS)
   ),
   div(
     id = "formreset",
     textInput("name", "Newform", "Dean"),
     radioButtons("gender", "Newform", c("Male", "Female")),
     selectInput("letter", "Newform letter", LETTERS)
   ),
   actionButton("reset_originalDiv", "Reset to original div"),
   actionButton("resetName", "Reset name"),
   actionButton("resetGender", "Reset Gender"),
   actionButton("change_div", "Change div")
 ),
 server = function(input, output) {
   observeEvent(input$resetName, {
     reset("name")
   })
   observeEvent(input$resetGender, {
     reset("gender")
   })
   observeEvent(input$change_div, {
     hide("form")
     show("formreset")
   })
   observeEvent(input$reset_originalDiv, {
     reset("form")
     hide("formreset")
     show("form")
   })
 }
)

As you can see, when clicking the "Reset to original div", the original div is not shown again.

Where is my mistake?

Thank you very much in advance.

CodePudding user response：

Up front: perhaps show(.) is not the show you think it is, use shinyjs::show.

Finding this: add a debugging step to one of the observeEvent blocks that calls show:

   observeEvent(input$change_div, {
     browser()
     hide("form")
     show("formreset")
   })

Run the app, then click on the appropriate button.

If we look at hide, it is what we think it should be:

Browse[2]> hide
function (id = NULL, anim = FALSE, animType = "slide", time = 0.5, 
    selector = NULL, asis = FALSE) 
{
    ...
}
<bytecode: 0x000000000a6a7538>
<environment: namespace:shinyjs>

However, perhaps show is not:

Browse[2]> show
standardGeneric for "show" defined from package "methods"

function (object) 
standardGeneric("show")
<bytecode: 0x000000001b740f30>
<environment: 0x000000001a823fb0>
Methods may be defined for arguments: object
Use  showMethods(show)  for currently available ones.
(This generic function excludes non-simple inheritance; see ?setIs)

This is showing us methods::show, whose first argument is indeed a character, and its return value is not really important to us in general, since shinyjs::show's return value is NULL, operating solely in side-effect. Because of what it does, we will get no warning or error indicating something might be amiss.

If you change all of your references to shinyjs::show, perhaps it will work.

Note: the first time I ran this app, it behaved as I just documented with the incorrect show. Once I tested the fix, now I cannot reproduce the problem with regular show("formreset"), so it is possible that something else may be going on. Using shinyjs::show is never wrong or different (unless you really are expecting to use a different show).

CodePudding user response：

I'm not positive on the why of the behavior, but if you remove the hide("formreset") and move reset("form") to the last call made in the observeEvent(input$reset_originalDiv... you get the behavior you're looking for.

observeEvent(input$reset_originalDiv, {
      shinyjs::show("form")
      reset("form")
      # hide("formreset")
    })

You might want to use toggle in an observe({}) block based on the style condition of the form div class, which when hidden is "display:none" to manage the formreset button.