Display the selected choice of a dynamically generated 'selectizeInput' widget based on the selected choice of previous widget

Question

I am trying to build a Shiny app that generates rows with multiple selectInput or selectizeInput widgets when a user presses the \"+\" button, and that removes such rows when he

Answer 1

Please see below for your first question:

library(shiny)
library(shinyjs)

###= UI
ui <- fluidPage(

br(),

useShinyjs(),

  fluidRow(
    column(width = 12,
           actionButton(inputId = "add_amr_test",
                        label = icon(name = "plus",
                                     lib = "font-awesome")),
           actionButton(inputId = "remove_amr_test",
                        label = icon(name = "minus",
                                     lib = "font-awesome")),
           div(style = "display: inline-block;
                        padding: 0px 10px;",
               h5("Add or remove an antimicrobial resistance test")),
           tags$div(id = "amr_test_placeholder")
    )
  ),

br()

)

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

  Antibiotics_name <- c("", "Amikacin", "Ampicillin", "Tetracycline")

  observe({

    toggleState(id = "remove_amr_test",
                condition = input$add_amr_test > input$remove_amr_test)

  })

  amr_test_values <- reactiveValues(val = 0)

  ###= Add ui
  observeEvent(input$add_amr_test, {

    amr_test_divId <- length(amr_test_values$val) + 1

    # Simplified input_number here and code to obtain previous values if they exist
    input_number <- input$add_amr_test - input$remove_amr_test
    if (!is.null(eval(parse(text = paste0("input$drug_", input_number - 1))))) {
        drug_value = eval(parse(text = paste0("input$drug_", input_number - 1)))
    } else {
        drug_value = ""
    }
    if (!is.null(eval(parse(text = paste0("input$rescom_", input_number - 1))))) {
        rescom_value = eval(parse(text = paste0("input$rescom_", input_number - 1)))
    } else {
        rescom_value = ""
    }

    insertUI(
      selector = "#amr_test_placeholder",
      where = "beforeBegin",
      ui = tags$div(
        id = amr_test_divId,
        fluidRow(

          br(),

          column(width = 3,
                 selectizeInput(inputId = paste0("drug_",
                                                 input_number),
                                label = h5(paste0("Antibiotic ",
                                                  input_number)),
                                choices = Antibiotics_name,
                                selected = drug_value)
          ),
          column(width = 1,
                 selectizeInput(inputId = paste0("rescom_",
                                                 input_number),
                                label = h5(paste0("AMR ",
                                                  input_number)),
                                choices = c("",
                                            seq(from = 1,
                                                to = 100,
                                                by = 1)),
                                selected = rescom_value)
          )
        )
      )
    )

    amr_test_values$val <- c(amr_test_values$val,
                             amr_test_divId)

  })

  ###= Remove ui
  observeEvent(input$remove_amr_test, {

    removeUI(

      selector = paste0('#', amr_test_values$val[length(amr_test_values$val)])

    )

    amr_test_values$val <- amr_test_values$val[-length(amr_test_values$val)]

  })

}



###= RUN APP
shinyApp(ui = ui, server = server)