if (interactive()) {
  
  
  server <- function(input, output) {
    observeEvent(input$goButton, {
    library(shiny)
    library(shinyjs)
    library(CTT)
    library(TAM)
    library(ltm)
    library(difR)
    
    
    
    
    
    output$contents <- renderTable({
      # input$file1 will be NULL initially. After the user selects
      # and uploads a file, it will be a data frame with 'name',
      # 'size', 'type', and 'datapath' columns. The 'datapath'
      # column will contain the local filenames where the data can
      # be found.
      inFile <- input$file1
      
      if (is.null(inFile))
        return(NULL)
      
      read.csv(inFile$datapath, header = input$header)
    })
    output$contents <- renderTable({
      # input$file1 will be NULL initially. After the user selects
      # and uploads a file, it will be a data frame with 'name',
      # 'size', 'type', and 'datapath' columns. The 'datapath'
      # column will contain the local filenames where the data can
      # be found.
      inFile <- input$file1
      
      if (is.null(inFile))
        return(NULL)
      
      read.csv(inFile$datapath, header = input$header)
    })
  }
  
  )}   
}
# your code goes here