Register expressions for export in test mode — exportTestValues

v1.7.3|Source: R/test-export.R

Description

This function registers expressions that will be evaluated when a test export event occurs. These events are triggered by accessing a snapshot URL.

exportTestValues(
  ...,
  quoted_ = FALSE,
  env_ = parent.frame(),
  session_ = getDefaultReactiveDomain()
)

Arguments

...

Named arguments that are quoted or unquoted expressions that will be captured and evaluated when snapshot URL is visited.

quoted_

Are the expression quoted? Default is FALSE.

env_

The environment in which the expression should be evaluated.

session_

A Shiny session object.

Details

This function only has an effect if the app is launched in test mode. This is done by calling runApp() with test.mode=TRUE, or by setting the global option shiny.testmode to TRUE.

Examples

## Only run this example in interactive R sessions
if (interactive()) {

options(shiny.testmode = TRUE)

# This application shows the test snapshot URL; clicking on it will
# fetch the input, output, and exported values in JSON format.
shinyApp(
  ui = basicPage(
    h4("Snapshot URL: "),
    uiOutput("url"),
    h4("Current values:"),
    verbatimTextOutput("values"),
    actionButton("inc", "Increment x")
  ),

  server = function(input, output, session) {
    vals <- reactiveValues(x = 1)
    y <- reactive({ vals$x + 1 })

    observeEvent(input$inc, {
      vals$x <<- vals$x + 1
    })

    exportTestValues(
      x = vals$x,
      y = y()
    )

    output$url <- renderUI({
      url <- session$getTestSnapshotUrl(format="json")
      a(href = url, url)
    })

    output$values <- renderText({
      paste0("vals$x: ", vals$x, "\ny: ", y())
    })
  }
)
}