The 'JavaScript' tunnel

Usage

register_session_id(
  session = shiny::getDefaultReactiveDomain(),
  shared_id = NULL,
  shared_inputs = NA
)

register_session_events(session = shiny::getDefaultReactiveDomain())

get_theme(event_data, session = shiny::getDefaultReactiveDomain())

get_jsevent(
  event_data,
  type,
  default = NULL,
  session = shiny::getDefaultReactiveDomain()
)

Arguments

session: shiny reactive domain
shared_id: the shared id of the session, usually automatically set
shared_inputs: the input names to share to/from other sessions
event_data: a reactive value list returned by register_session_events
type: event type; see 'Details'
default: default value if type is missing

Value

register_session_id returns a list of function to control "sharing" inputs with other shiny sessions with the same shared_id. register_session_events returns a reactive value list that reflects the session state. get_jsevent returns events fired by shidashi.broadcastEvent in 'JavaScript'. get_theme returns a list of theme, foreground, and background color.

Details

The register_session_id should be used in the module server function. It registers a shared_id and a private_id to the session. The sessions with the same shared_id can synchronize their inputs, specified by shared_inputs even on different browser tabs.

register_session_events will read the session events from 'JavaScript' and passively update these information. Any the event fired by shidashi.broadcastEvent in 'JavaScript' will be available as reactive value. get_jsevent provides a convenient way to read these events provided the right event types. get_theme is a special get_jsevent that with event type "theme.changed".

Function register_session_id and register_session_events should be called at the beginning of server functions. They can be called multiple times safely. Function get_jsevent and get_theme should be called in reactive contexts (such as observe, observeEvent).

Examples


# shiny server function

library(shiny)
server <- function(input, output, session){
  sync_tools <- register_session_id(session = session)
  event_data <- register_session_events(session = session)

  # if you want to enable syncing. They are suspended by default
  sync_tools$enable_broadcast()
  sync_tools$enable_sync()

  # get_theme should be called within reactive context
  output$plot <- renderPlot({
    theme <- get_theme(event_data)
    mar(bg = theme$background, fg = theme$foreground)
    plot(1:10)
  })

}