Pass shiny DT cell value to function

Question

I have a datatable that I construct using function1 and user input. I then want to use a cell value from this datatable as input to function2 to build another datatable. I am getting a filter error and think the issue is related to how I am selecting cell values. I am building of an existing SO solution here.

Assume we have iris data and function1 uses the user input to filter on species. The result of function1 is a result of a reactive call. Now function2 takes this result as input and uses the selected "cell" value (Sepal.Length) to further filter and build another datatable.

Thanks the comment by @Silentdevildoll, table2 is being constructed correctly (I think) but I still see this error:

Warning: Error in : Problem with filter() input ..1. i Input ..1 is Sepal.Length == var. x Input ..1 must be of size 50 or 1, not size 0.

library(shiny)
library(DT)

ui <- fluidPage(
 
  mainPanel(
    fluidRow(
      column(4, textInput('textInput1', label=NULL)),
      column(1, actionButton('button1', label=NULL))
    ),
    fluidRow(
      column(8, DT::dataTableOutput("table1")),
      column(4, DT::dataTableOutput("table2"))
    )
  )
)

server <- function(input, output, session){
  
   data(iris)



function1 <- function(id){
    return(dplyr::filter(iris, Species==id))
  }
  
  function2 <- function(df, var){
    return(dplyr::filter(df, Sepal.Length==var))  
  }
  
  data <- reactiveValues()
  
  observeEvent(input$button1, { data$ID <- input$textInput1 })

  table1_rec <- reactive({ function1(data$ID) })
  
  output$table1 <- DT::renderDataTable({
    req(data$ID)
    DT::datatable(table1_rec(), selection = list(target = 'cell'))
                    
  })
  
  table2_rec <- reactive({ 
    selected = table1_rec()[input$table1_cells_selected]
    function2(table1_rec(), selected) 
  })
  
  output$table2 <- DT::renderDataTable({
    DT::datatable(table2_rec())
  })

}

shinyApp(ui, server)