如何从闪亮的textInput更新字符向量？

Question

I want to add the input text to a vector in a Shiny app every time a button is clicked. This is the example I'm working with:

library(shiny)
ui <- fluidPage(
     textInput(inputId = "inquiry", label = "enter text"),
     actionButton(inputId = "searchButton", label = "Run"),
     verbatimTextOutput("queryList", placeholder = FALSE)
)
server <- function(input, output, session) {
     queryList <- c()
     observeEvent(input$searchButton, {
          queryList[length(queryList)+1] <- input$inquiry
          output$queryList <- renderPrint({
               queryList
          })
     })
}
shinyApp(ui = ui, server = server)

So if "item1" is entered and the button is clicked, then "item2" is entered and the button is clicked again, queryList should look like c("item1", "item2") , but it seems to just be replacing "item1" with "item2" . I'm sure I'm missing something very simple... queryList[length(queryList)+1] looks a little strange, but it works in a non-reactive environment.

Answer 1

Making queryList reactive fixed it for me:

library(shiny)

ui <- fluidPage(
  textInput(inputId = "inquiry", label = "enter text"),
  actionButton(inputId = "searchButton", label = "Run"),
  verbatimTextOutput("queryList", placeholder = FALSE)
)

server <- function(input, output, session) {
  queryList <- reactiveValues()
  queryList$values <- c()

  observeEvent(input$searchButton, {
    queryList$values[length(queryList$values) + 1] <- input$inquiry
  })

  output$queryList <- renderPrint({
    if (!is.null(queryList$values)) {
      queryList$values
    }
  })
}

shinyApp(ui = ui, server = server)