R Shiny renderTable – freeze columns

Your two questions are very different. I reply to the second one. Please open another question for the first one.

The solution I propose makes use of the jQuery plugin freeze Table.

library(shiny)

widetbl <- t(iris[1:40,]) # a wide table for the illustration

js <- HTML(paste0(c(
  '$(document).on("shiny:value", function(evt) {',
  '  if(evt.name === "wideTable") {',
  '    setTimeout(function() {',
  '      $("#wideTable").freezeTable({',
  '        fastMode: true,',
  '       columnNum: 2',
  '      });',
  '    }, 0);',
  '  }',
  '});'
), collapse = "\n"))

ui <- fluidPage(
  tags$head(
    tags$script(
      src = "https://cdn.jsdelivr.net/gh/yidas/jquery-freeze-table/dist/js/freeze-table.min.js"
    ),
    tags$script(js)
  ),
  br(),
  tableOutput("wideTable")
)

server <- function(input, output, session){
  
  output[["wideTable"]] <- renderTable({
    widetbl
  })
  
}

shinyApp(ui, server)