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<!-- Generated by pkgdown: do not edit by hand --><html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Timer — reactiveTimer • shiny</title><!-- jquery --><script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js" integrity="sha512-v2CJ7UaYy4JwqLDIrZUI/4hqeoQieOmAZNXBeQyjo21dadnwR+8ZaIJVT8EE2iyI61OV8e6M8PP2/4hpQINQ/g==" crossorigin="anonymous" referrerpolicy="no-referrer"></script><!-- Bootstrap --><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/css/bootstrap.min.css" integrity="sha256-bZLfwXAP04zRMK2BjiO8iu9pf4FbLqX6zitd+tIvLhE=" crossorigin="anonymous"><script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/js/bootstrap.min.js" integrity="sha256-nuL8/2cJ5NDSSwnKD8VqreErSWHtnEP9E7AySL+1ev4=" crossorigin="anonymous"></script><!-- bootstrap-toc --><link rel="stylesheet" href="../bootstrap-toc.css"><script src="../bootstrap-toc.js"></script><!-- Font Awesome icons --><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.12.1/css/all.min.css" integrity="sha256-mmgLkCYLUQbXn0B1SRqzHar6dCnv9oZFPEC1g1cwlkk=" crossorigin="anonymous"><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.12.1/css/v4-shims.min.css" integrity="sha256-wZjR52fzng1pJHwx4aV2AO3yyTOXrcDW7jBpJtTwVxw=" crossorigin="anonymous"><!-- clipboard.js --><script src="https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/2.0.6/clipboard.min.js" integrity="sha256-inc5kl9MA1hkeYUt+EC3BhlIgyp/2jDIyBLS6k3UxPI=" crossorigin="anonymous"></script><!-- headroom.js --><script src="https://cdnjs.cloudflare.com/ajax/libs/headroom/0.11.0/headroom.min.js" integrity="sha256-AsUX4SJE1+yuDu5+mAVzJbuYNPHj/WroHuZ8Ir/CkE0=" crossorigin="anonymous"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/headroom/0.11.0/jQuery.headroom.min.js" integrity="sha256-ZX/yNShbjqsohH1k95liqY9Gd8uOiE1S4vZc+9KQ1K4=" crossorigin="anonymous"></script><!-- pkgdown --><link href="../pkgdown.css" rel="stylesheet"><script src="../pkgdown.js"></script><meta property="og:title" content="Timer — reactiveTimer"><meta property="og:description" content="Creates a reactive timer with the given interval. A reactive timer is like a
reactive value, except reactive values are triggered when they are set, while
reactive timers are triggered simply by the passage of time."><meta property="og:image" content="/logo.png"><!-- mathjax --><script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/MathJax.js" integrity="sha256-nvJJv9wWKEm88qvoQl9ekL2J+k/RWIsaSScxxlsrv8k=" crossorigin="anonymous"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/config/TeX-AMS-MML_HTMLorMML.js" integrity="sha256-84DKXVJXs0/F8OTMzX4UR909+jtl4G7SPypPavF+GfA=" crossorigin="anonymous"></script><!--[if lt IE 9]>
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<h1>Timer</h1>
<small class="dont-index">Source: <a href="https://github.com/rstudio/shiny/blob/rc-v1.12.1/R/reactives.R" class="external-link"><code>R/reactives.R</code></a></small>
<div class="hidden name"><code>reactiveTimer.Rd</code></div>
</div>
<div class="ref-description">
<p>Creates a reactive timer with the given interval. A reactive timer is like a
reactive value, except reactive values are triggered when they are set, while
reactive timers are triggered simply by the passage of time.</p>
</div>
<div id="ref-usage">
<div class="sourceCode"><pre class="sourceCode r"><code><span><span class="fu">reactiveTimer</span><span class="op">(</span>intervalMs <span class="op">=</span> <span class="fl">1000</span>, session <span class="op">=</span> <span class="fu"><a href="domains.html">getDefaultReactiveDomain</a></span><span class="op">(</span><span class="op">)</span><span class="op">)</span></span></code></pre></div>
</div>
<div id="arguments">
<h2>Arguments</h2>
<dl><dt id="arg-intervalms">intervalMs<a class="anchor" aria-label="anchor" href="#arg-intervalms"></a></dt>
<dd><p>How often to fire, in milliseconds</p></dd>
<dt id="arg-session">session<a class="anchor" aria-label="anchor" href="#arg-session"></a></dt>
<dd><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></dd>
</dl></div>
<div id="value">
<h2>Value</h2>
<p>A no-parameter function that can be called from a reactive context,
in order to cause that context to be invalidated the next time the timer
interval elapses. Calling the returned function also happens to yield the
current time (as in <code><a href="https://rdrr.io/r/base/Sys.time.html" class="external-link">base::Sys.time()</a></code>).</p>
</div>
<div id="details">
<h2>Details</h2>
<p><a href="reactive.html">Reactive expressions</a> and observers that want to be
invalidated by the timer need to call the timer function that
<code>reactiveTimer</code> returns, even if the current time value is not actually
needed.</p>
<p>See <code><a href="invalidateLater.html">invalidateLater()</a></code> as a safer and simpler alternative.</p>
</div>
<div id="see-also">
<h2>See also</h2>
<div class="dont-index"><p><code><a href="invalidateLater.html">invalidateLater()</a></code></p></div>
</div>
<div id="ref-examples">
<h2>Examples</h2>
<div class="sourceCode"><pre class="sourceCode r"><code><span class="r-in"><span><span class="co">## Only run examples in interactive R sessions</span></span></span>
<span class="r-in"><span><span class="kw">if</span> <span class="op">(</span><span class="fu"><a href="https://rdrr.io/r/base/interactive.html" class="external-link">interactive</a></span><span class="op">(</span><span class="op">)</span><span class="op">)</span> <span class="op">{</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="va">ui</span> <span class="op">&lt;-</span> <span class="fu"><a href="fluidPage.html">fluidPage</a></span><span class="op">(</span></span></span>
<span class="r-in"><span> <span class="fu"><a href="sliderInput.html">sliderInput</a></span><span class="op">(</span><span class="st">"n"</span>, <span class="st">"Number of observations"</span>, <span class="fl">2</span>, <span class="fl">1000</span>, <span class="fl">500</span><span class="op">)</span>,</span></span>
<span class="r-in"><span> <span class="fu"><a href="plotOutput.html">plotOutput</a></span><span class="op">(</span><span class="st">"plot"</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="va">server</span> <span class="op">&lt;-</span> <span class="kw">function</span><span class="op">(</span><span class="va">input</span>, <span class="va">output</span><span class="op">)</span> <span class="op">{</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span> <span class="co"># Anything that calls autoInvalidate will automatically invalidate</span></span></span>
<span class="r-in"><span> <span class="co"># every 2 seconds.</span></span></span>
<span class="r-in"><span> <span class="va">autoInvalidate</span> <span class="op">&lt;-</span> <span class="fu">reactiveTimer</span><span class="op">(</span><span class="fl">2000</span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span> <span class="fu"><a href="observe.html">observe</a></span><span class="op">(</span><span class="op">{</span></span></span>
<span class="r-in"><span> <span class="co"># Invalidate and re-execute this reactive expression every time the</span></span></span>
<span class="r-in"><span> <span class="co"># timer fires.</span></span></span>
<span class="r-in"><span> <span class="fu">autoInvalidate</span><span class="op">(</span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span> <span class="co"># Do something each time this is invalidated.</span></span></span>
<span class="r-in"><span> <span class="co"># The isolate() makes this observer _not_ get invalidated and re-executed</span></span></span>
<span class="r-in"><span> <span class="co"># when input$n changes.</span></span></span>
<span class="r-in"><span> <span class="fu"><a href="https://rdrr.io/r/base/print.html" class="external-link">print</a></span><span class="op">(</span><span class="fu"><a href="https://rdrr.io/r/base/paste.html" class="external-link">paste</a></span><span class="op">(</span><span class="st">"The value of input$n is"</span>, <span class="fu"><a href="isolate.html">isolate</a></span><span class="op">(</span><span class="va">input</span><span class="op">$</span><span class="va">n</span><span class="op">)</span><span class="op">)</span><span class="op">)</span></span></span>
<span class="r-in"><span> <span class="op">}</span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span> <span class="co"># Generate a new histogram each time the timer fires, but not when</span></span></span>
<span class="r-in"><span> <span class="co"># input$n changes.</span></span></span>
<span class="r-in"><span> <span class="va">output</span><span class="op">$</span><span class="va">plot</span> <span class="op">&lt;-</span> <span class="fu"><a href="renderPlot.html">renderPlot</a></span><span class="op">(</span><span class="op">{</span></span></span>
<span class="r-in"><span> <span class="fu">autoInvalidate</span><span class="op">(</span><span class="op">)</span></span></span>
<span class="r-in"><span> <span class="fu"><a href="https://rdrr.io/r/graphics/hist.html" class="external-link">hist</a></span><span class="op">(</span><span class="fu"><a href="https://rdrr.io/r/stats/Normal.html" class="external-link">rnorm</a></span><span class="op">(</span><span class="fu"><a href="isolate.html">isolate</a></span><span class="op">(</span><span class="va">input</span><span class="op">$</span><span class="va">n</span><span class="op">)</span><span class="op">)</span><span class="op">)</span></span></span>
<span class="r-in"><span> <span class="op">}</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="op">}</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="fu"><a href="shinyApp.html">shinyApp</a></span><span class="op">(</span><span class="va">ui</span>, <span class="va">server</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="op">}</span></span></span>
</code></pre></div>
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