当单击指定输入以外的任何操作或其他按钮时，如何在 R Shiny 中使用 js 隐藏条件面板？

Question

I am trying to hide the conditional panel illustrated below when there is any user input other than the user clicking on the action button "Delete" or making a selection in the selectInput() function rendered in the conditional panel, as shown in the below image. Other user inputs will be added (action buttons, radio buttons, selectInputs, etc.) so it isn't feasible to list each action that causes the conditional panel to hide. That conditional panel should always render upon the click of "Delete". Any suggestions for how to do this? Code is shown at the bottom.

Code:

library(rhandsontable)
library(shiny)

mydata <- data.frame('Col 1' = c(1,24,0,1), check.names = FALSE)
rownames(mydata) <- c('Term A','Term B','Term C','Term D') 

ui <- fluidPage(br(),
      rHandsontableOutput("mytable"),br(),
        fluidRow(
          column(1,actionButton("addCol", "Add",width = '70px')),
          column(1,actionButton("delCol","Delete",width = '70px')),
          column(3,conditionalPanel(condition = "input.delCol",uiOutput("delCol"))) # js here
        )
)

server <- function(input, output) {
  
  output$mytable = renderRHandsontable(df())
  
  df <- eventReactive(input$addCol, {
    if(input$addCol > 0){
      newcol <- data.frame(mydata[,1])
      names(newcol) <- paste("Col",ncol(mydata)+1)
      mydata <<- cbind(mydata, newcol)
    }
    rhandsontable(mydata,rowHeaderWidth = 100, useTypes = TRUE)
  }, ignoreNULL = FALSE)
  
  observeEvent(input$delCol,
    {output$delCol<-renderUI(selectInput("delCol",label=NULL,choices=colnames(mydata),selected="Col 1"))}
    )
  
}

shinyApp(ui,server)

Answer 1

Per Mike´s comment I started with shinyjs and this simple example from the shinyjs reference manual, with minor modification for 2 buttons:

library(shiny)
library(shinyjs)

ui = fluidPage(
       useShinyjs(), # Set up shinyjs
       actionButton("btn", "Click to show"),
       actionButton("btn1","Click to hide"),
       hidden(p(id = "element", "I was invisible"))
     )

server = function(input, output) {
  observeEvent(input$btn, {show("element")})
  observeEvent(input$btn1,{hide("element")})
  }

shinyApp(ui,server)

Then I expanded it to my code in the OP per the below. Note that this will still require an observeEvent() for each user action that triggers selectInput() to hide instead of a global hide every time there's any user input other than a click of "Delete" action button. I'm not sure this is possible but will continue researching. Multiple observeEvents() won't be too bad of an option in any case.

Resolving code:

library(rhandsontable)
library(shiny)
library(shinyjs)

mydata <- data.frame('Col 1' = c(1,24,0,1), check.names = FALSE)
rownames(mydata) <- c('Term A','Term B','Term C','Term D') 

ui <- fluidPage(
  useShinyjs(), # set up shinyjs
  br(),
  rHandsontableOutput("mytable"),br(),
  fluidRow(
    column(1,actionButton("addCol", "Add",width = '70px')),
    column(1,actionButton("delCol","Delete",width = '70px')),
    column(3, hidden(uiOutput("delCol2")))) # hide selectInput()
)

server <- function(input,output,session){
  
  output$mytable = renderRHandsontable(dat())
  
  dat <- eventReactive(input$addCol, {
    if(input$addCol > 0){
      newcol <- data.frame(mydata[,1])
      names(newcol) <- paste("Col",ncol(mydata)+1)
      mydata <<- cbind(mydata, newcol)
    }
    rhandsontable(mydata,rowHeaderWidth = 100, useTypes = TRUE)
  }, ignoreNULL = FALSE)
  
  observeEvent(input$delCol, show("delCol2")) # clicking Delete button reveals selectInput()
   
  observeEvent(input$addCol, hide("delCol2")) # clicking Add hides selectInput()
  
  output$delCol2 <-renderUI({
    selectInput(
      "delCol3",
      label=NULL,
      choices=colnames(mydata),
      selected="Col 1"
    )
  })
  
}

shinyApp(ui,server)