How to listen for more than one event expression within a Shiny observeEvent

Question

I want two different events to trigger an observer. It was suggested here that this should work. But it seems that it depends only on the second event.

obser         


        

Answer 1

observeEvent is a wrapper for complex observe cases. In this particular case of an action when one or other reactive value changes, one could use a simple observe. This works:

require(shiny)    
ui <- basicPage(
      actionButton("test1", "test1"),
      actionButton("test2", "test2")
    )
    
    server <- function(input, output, session){
    
      observe( {
        input$test1
        input$test2
        if(input$test1==0 && input$test2==0){
          return()
        }
        print('Hello World')
        })
    }
    
    shinyApp(ui, server)

There is a point in using observeEvent with options to eliminate the return() call:

ui <- basicPage(
  actionButton("test1", "test1"),
  actionButton("test2", "test2")
)

server <- function(input, output, session){

  observeEvent(input$test1 | input$test2, { print('Hello World') } , ignoreInit = TRUE)
}

shinyApp(ui, server)