In R shiny, when using tibble function of tidyverse package, why does my App crash?

Question

The below code runs fine so long as the line in server section v <- reactiveValues(results=tibble(Scenario = 1, data())) is commented out. When I uncomment it the App crashes and I get the error message: Warning: Error in : Can't access reactive value 'input1' outside of reactive consumer. i Do you need to wrap inside reactive() or observer()?

I'm trying to create a vector using tibble for another function to be added. What am I doing wrong here in my use of tibble? I'm trying to capture via tibble, as a vector, the values generated by my custom interpol function when it takes inputs from matrix input2 through the data() function below. I also tried c(), as.vector(), etc., to make sure input2 is converted to a vector but I still get the same error.

I'm completely new to tibbles and tidyverse etc.

Code:

library(shiny)
library(shinyMatrix)
library(tidyverse) # < ADDED

interpol <- function(a,b){ # a = periods, b = matrix inputs
  c    <- rep(NA,a)
  c[1] <- b[1]
  c[a] <- b[2]
  c <- approx(seq_along(c)[!is.na(c)],c[!is.na(c)],seq_along(c))$y # this interpolates
  return(c)
}

ui <- fluidPage(
    sidebarLayout(
      sidebarPanel(uiOutput("panel"),actionButton("showInput2","Modify/add interpolation")),
      mainPanel(plotOutput("plot"))
    )
  )

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

data <- function(){
  if(!isTruthy(input$input1)){interpol(6,matrix(c(1,5)))} else {
    if(!isTruthy(input$input2)){interpol(input$periods,
      matrix(c(input$input1[1,1],input$input1[1,2])))} else {
        interpol(input$periods,matrix(c(input$input2[1,1],input$input2[1,2])))}}
  }  

  # v <- reactiveValues(results=tibble(Scenario = 1, data()))
  
  output$panel <- renderUI({
    tagList(
      sliderInput('periods','Interpolate over periods (X):',min=2,max=12,value=6),
      uiOutput("input1"))
  })

  output$input1 <- renderUI({
    matrixInput("input1", 
                label = "Interpolation 1 (Y values):",
                value =  matrix(if(isTruthy(input$input2)){c(input$input2[1],input$input2[2])} 
                                  else {c(1,5)},                          # matrix values
                                1, 2,                                     # matrix row/column count
                                dimnames = list(NULL,c("Start","End"))),  # matrix column header
                rows =  list(names = FALSE), class = "numeric")
  })
  
  observeEvent(input$showInput2,{
    showModal(
      modalDialog(
        matrixInput("input2",
          label = "Automatically numbered scenarios (input into blank cells to add):",
          value = if(isTruthy(input$input2)){input$input2}
                  else if(isTruthy(input$input1)){input$input1},
          rows =  list(names = FALSE),
          cols =  list(extend = TRUE, delta = 2, delete = TRUE, multiheader=TRUE),
          class = "numeric"),
    footer = modalButton("Close")
    ))
  })

  observe({
    req(input$input2)
    mm <- input$input2
    colnames(mm) <- paste(trunc(1:ncol(mm)/2)+1, " (start|end)")
    isolate(updateMatrixInput(session, "input2", mm))
  })
  
  output$plot<-renderPlot({plot(data(),type="l",xlab="Periods (X)", ylab="Interpolated Y values")})
  
}

shinyApp(ui, server)

Answer 1

The reason for the error and solution actually is present in the error message itself. You cannot access reactive variable (data()) outside reactive context. Try wrapping the v output in reactive.

v <- reactive({tibble(Scenario = 1, data())})