reactiveTimer

From shiny v0.9.1 by Winston Chang

Timer

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.

Usage

reactiveTimer(intervalMs = 1000, session)

Details

Reactive expressions and observers that want to be invalidated by the timer need to call the timer function that reactiveTimer returns, even if the current time value is not actually needed.

See invalidateLater as a safer and simpler alternative.

Value

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 Sys.time).

Examples

shinyServer(function(input, output, session) {

  # Anything that calls autoInvalidate will automatically invalidate
  # every 2 seconds.
  autoInvalidate <- reactiveTimer(2000, session)

  observe({
    # Invalidate and re-execute this reactive expression every time the
    # timer fires.
    autoInvalidate()

    # 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 each time the timer fires, but not when
  # input$n changes.
  output$plot <- renderPlot({
    autoInvalidate()
    hist(isolate(input$n))
  })
})

Documentation reproduced from package shiny, version 0.9.1, License: GPL-3

Community examples

Looks like there are no examples yet.