In shiny app, when a column is deleted, the column header is not deleted accordingly. Results in an error when call "Excel_to_R" function. #91

library(excelR)
library(shiny)

ui <- fluidPage(
  excelOutput("tab")
)

server <- function(input, output, session) {
  df <- data.frame(
    l = c("A", "B"),
    n = 1:2,
    stringsAsFactors = FALSE
  )
  output$tab <- renderExcel(
    excelTable(df)
  )
  
  observe(
    print(input$tab)
  )
}

shinyApp(ui, server)

$data
$data[[1]]
$data[[1]][[1]]
[1] "A"

$data[[2]]
$data[[2]][[1]]
[1] "B"

$col Headers
$colHeaders[[1]]
[1] "l"

$colHeaders[[2]]
[1] "n"

$colType
$colType[[1]]
[1] "text"

$forSelectedVals
[1] FALSE

$data
$data[[1]]
$data[[1]][[1]]
[1] "A"

$data[[2]]
$data[[2]][[1]]
[1] "B"

$colHeaders
$colHeaders[[1]]
[1] "l"

$colType
$colType[[1]]
[1] "text"

$forSelectedVals
[1] FALSE