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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/reactives.R
\title{Scheduled Invalidation}
invalidateLater(millis, session = getDefaultReactiveDomain())
\item{millis}{Approximate milliseconds to wait before invalidating the
current reactive context.}
\item{session}{A session object. This is needed to cancel any scheduled
invalidations after a user has ended the session. If \code{NULL}, then
this invalidation will not be tied to any session, and so it will still
Schedules the current reactive context to be invalidated in the given number
of milliseconds.
If this is placed within an observer or reactive expression, that object will
be invalidated (and re-execute) after the interval has passed. The
re-execution will reset the invalidation flag, so in a typical use case, the
object will keep re-executing and waiting for the specified interval. It's
possible to stop this cycle by adding conditional logic that prevents the
\code{invalidateLater} from being run.
## Only run examples in interactive R sessions
if (interactive()) {
ui <- fluidPage(
sliderInput("n", "Number of observations", 2, 1000, 500),
server <- function(input, output, session) {
# Re-execute this reactive expression after 1000 milliseconds
invalidateLater(1000, session)
# Do something each time this is invalidated.
# The isolate() makes this observer _not_ get invalidated and re-executed
# when input$n changes.
print(paste("The value of input$n is", isolate(input$n)))
# Generate a new histogram at timed intervals, but not when
# input$n changes.
output$plot <- renderPlot({
# Re-execute this reactive expression after 2000 milliseconds
shinyApp(ui, server)
\code{\link{reactiveTimer}} is a slightly less safe alternative.