EVOLUTION-MANAGER

Edit File: invalidateLater.html

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<table width="100%" summary="page for invalidateLater {shiny}"><tr><td>invalidateLater {shiny}</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Scheduled Invalidation</h2>

<h3>Description</h3>

<p>Schedules the current reactive context to be invalidated in the given number
of milliseconds.
</p>

<h3>Usage</h3>

<pre>
invalidateLater(millis, session = getDefaultReactiveDomain())
</pre>

<h3>Arguments</h3>

<table summary="R argblock">
<tr valign="top"><td><code>millis</code></td>
<td>
<p>Approximate milliseconds to wait before invalidating the
current reactive context.</p>
</td></tr>
<tr valign="top"><td><code>session</code></td>
<td>
<p>A session object. This is needed to cancel any scheduled
invalidations after a user has ended the session. If <code>NULL</code>, then
this invalidation will not be tied to any session, and so it will still
occur.</p>
</td></tr>
</table>

<h3>Details</h3>

<p>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</code> from being run.
</p>

<p><code><a href="reactiveTimer.html">reactiveTimer()</a></code> is a slightly less safe alternative.
</p>

<h3>Examples</h3>

<pre>
## Only run examples in interactive R sessions
if (interactive()) {

ui &lt;- fluidPage(
  sliderInput("n", "Number of observations", 2, 1000, 500),
  plotOutput("plot")
)

server &lt;- function(input, output, session) {

observe({
    # 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 &lt;- renderPlot({
    # Re-execute this reactive expression after 2000 milliseconds
    invalidateLater(2000)
    hist(rnorm(isolate(input$n)))
  })
}

shinyApp(ui, server)
}
</pre>

<hr /><div style="text-align: center;">[Package <em>shiny</em> version 1.5.0 <a href="00Index.html">Index</a>]</div>
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