R Shiny - conditionnal panel based on list

Question

Yes, there are many questions phrased very similary, for instance

r shiny - conditionalPanel with condition: check item in list or Multiple conditions in condition panel R shiny

None, however, seems to sort the problem - that in addition seems to be one of js syntax more than R proper.

Consider the following MRE:

library(shiny)

collective <- c("happiness","love","peace","time","foo","bar")
numerable <- c("apple","orange","banana","quux","baz","bob")

ui <- fluidPage(
  
  selectInput("choice","choose one",choices=c(collective,numerable)),
  
    conditionalPanel(
    condition = TRUE, ## This is the condition I need to write !
    numericInput("number",
                "How many?",
                value=3)
  ),
  
  
  textOutput("result")
)

server <- function(input, output, session) {
  
  output$result <- renderText({
    
    if(is.null(input$number)){
      paste("You want some", input$choice)
    }else{
      paste("you want",input$number,input$choice)
    }
  })
}

shinyApp(ui = ui, server = server)

Here I want to show the number box only if the user choices something that can be counted.

In plain R, I would write my condition as if(input$choice %in% numerable) ... etc.

However the condition must be written in js at that point.

The question is therefore, how do I translate this R statement into a js condition that will work in this context ?

Similar questions got the following answers, or perhaps workarounds:

1) Use a renderUI instead, which can be coded in R like so:

    output$numberUI <- renderUI({
        if( input$choice %in% numerable) {
            # pass
        }else{
              numericInput("number",
              "How many?",
              value=3)
            }
    })

and replace the conditional panel by uiOutput("numberUI"). This works indeed, in actual fact this is what I'm doing now in my "real" app, but I find the resulting code to be less readable with the UI definition scattered between UI and server.

2) Explicitly list all the possible cases with condition = "input.choice == 'apple' || input.choice =='orange' || input.choice == 'banana' " ... etc., which is obviously clumsy and error prone (and in addition will not work if the list of numerable is data-driven, in my case it is in the real app based on names(the_data) ).

I'm pretty sure that js has an operator equivalent to R's %in% so the question boils down to how do I translate this R statement: input$choice %in% numerable to js ? The obvious "input.choice in numerable" does not work, presumably because I first need to convert numerable to a js object ?

EDIT: based on Stéphane Laurent's below. I realized that of course condition is a string, so nothing stops me from creating the condition string dynamically. And so:

condition = paste('[',paste(paste('"',numerable,'"',sep=''),collapse=','),'].includes(input.choice)',sep='')

... if somewhat unreadable (it can be prettified with pipes, glue etc) does the job.

Answer 1

Try

condition = '["apple","orange","banana","quux","baz","bob"].includes(input.choice)'

or

condition = '["apple","orange","banana","quux","baz","bob"].indexOf(input.choice) > -1'