How does input from insertUI get stored? - r

Question

I've created a SelectizeInput() UI using the insertUI() function. Essentially, I have an action button which adds a SelectizeInput() every time it's clicked. The idea is that the user selects columns from their data to put into groups. The creation of the UI works fine. I can also see in the Shiny trace that the selection works fine. However, I'm unsure how to access these variables to use in later plots. This is the code I have:
UI:
actionButton("cr_exp", "Create new biological group")
Server:
observeEvent(input$cr_exp, {
insertUI(
selector = "#cr_exp",
where = "afterEnd",
ui = selectizeInput(inputId = paste0("grp", input$cr_exp), label = "Select samples", choices = colnames(exp_dff()), options = list(create=TRUE), multiple=TRUE))
tags$div(id = paste0("grp", input$cr_exp))
})
In the shiny trace, it shows that the group is created, but I can't figure out how to access the value:
RECV {"method":"update","data":{"grp1":["MV4negControl01","MV4negControl02"]}}

Answer 1

You access the values just like any other input values: by the input element’s
id from the input reactive values:
library(shiny)
ui <- fluidPage(
actionButton("cr_exp", "Create new biological group"),
verbatimTextOutput("choices")
)
server <- function(input, output, session) {
observeEvent(input$cr_exp, {
insertUI(
selector = "#cr_exp",
where = "afterEnd",
ui = selectizeInput(
inputId = paste0("grp", input$cr_exp),
label = "Select samples",
choices = LETTERS,
options = list(create = TRUE),
multiple = TRUE
)
)
tags$div(id = paste0("grp", input$cr_exp))
})
output$choices <- renderPrint({
lapply(seq_len(input$cr_exp), function(i) input[[paste0("grp", i)]])
})
}
shinyApp(ui, server)