Btukfyl

Is there any solution to back into current state of app when user will click submit button. If one condition won't be met app display info and back to initial UI.

observeEvent(input$sub, {

if (input$test == TRUE) {

  shinyalert("You made error", type = "error")

  stop () #need back initial state before click button stop() stops app completely

}

}

You can use library(shinyjs) to reset the session. Here is an example following your provided observeEvent:

library(shiny)

library(shinyalert)

library(shinyjs)



jsResetCode <- "shinyjs.reset = function() {history.go(0)}"



ui <- fluidPage(

  useShinyalert(),

  useShinyjs(),

  extendShinyjs(text = jsResetCode),



   titlePanel("Old Faithful Geyser Data"),



   sidebarLayout(

      sidebarPanel(

        actionButton("sub","sub"),

        checkboxInput("test", "test"),

         sliderInput("bins",

                     "Number of bins:",

                     min = 1,

                     max = 50,

                     value = 30)

      ),



      mainPanel(

         plotOutput("distPlot")

      )

   )

)



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



  observeEvent(input$sub, {

    if(input$test == TRUE){

      shinyalert("You made error", type = "error")

    }

  })



  observeEvent(input$shinyalert, {

    if(input$shinyalert == TRUE){

      js$reset()

    }

  })



   output$distPlot <- renderPlot({

      x    <- faithful[, 2] 

      bins <- seq(min(x), max(x), length.out = input$bins + 1)

      hist(x, breaks = bins, col = 'darkgray', border = 'white')

   })

}



shinyApp(ui = ui, server = server)