only refresh shiny plot at launch and if action button is clicked

Question

I want to render shiny plots on launch and then require clicking the action button to re-render. I tried to simplify my app to post here. As you can, see changing the "week" selection triggers a refresh. how do I suppress all refreshes unless action Is clicked?

library(shiny); library(dplyr); library(ggplot2)

#toy data
dates= seq.Date(as.Date("2020-01-01"),as.Date("2020-05-01"),by="days")
set.seed(1)
data = data.frame(date = dates,val = runif(length(dates),50,150))

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      selectInput("group","Group",choices = LETTERS[1:3]),
      dateRangeInput('dateRangeCal', "Input date range"),
      selectInput("week","shift week",choices = c(0:3)),
      actionButton("action","Submit")
    ),
    mainPanel(
      plotOutput(outputId = "plot")
    )
  )
)

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

  observeEvent( input$action, {
    startDate = as.Date("2020-01-01")+days(case_when(
      input$group == "A" ~ 0,
      input$group == "B" ~ 30,
      input$group == "C" ~ 60
    ))
    endDate=startDate+days(60)
    updateDateRangeInput(session = session, 
                         inputId = 'dateRangeCal',
                         label = 'Date range input:',
                         start = startDate,
                         end = endDate
    )

  },ignoreNULL = F)

  output$plot <- renderPlot({
    p = data %>%
      filter(date>=input$dateRangeCal[1]+days(input$week)*7,date<=input$dateRangeCal[2]) %>%
      ggplot(.,aes(x=date,y=val))+
      geom_line()
    p
  })
}

shinyApp(ui, server)

Answer 1

Would this work?

library(shiny); library(dplyr); library(ggplot2); library(lubridate)

#toy data
dates= seq.Date(as.Date("2020-01-01"),as.Date("2020-05-01"),by="days")
set.seed(1)
data = data.frame(date = dates,val = runif(length(dates),50,150))

ui <- fluidPage(
    sidebarLayout(
        sidebarPanel(
            selectInput("group","Group",choices = LETTERS[1:3]),
            dateRangeInput('dateRangeCal', "Input date range"),
            selectInput("week","shift week",choices = c(0:3)),
            actionButton("action","Submit")
        ),
        mainPanel(
            plotOutput(outputId = "plot")
        )
    )
)

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

    observeEvent(input$action, {
        grp <- isolate(input$group)
        startDate = as.Date("2020-01-01")+days(case_when(
            grp == "A" ~ 0,
            grp == "B" ~ 30,
            grp == "C" ~ 60
        ))
        endDate=startDate+days(60)
        updateDateRangeInput(session = session, 
                             inputId = 'dateRangeCal',
                             label = 'Date range input:',
                             start = startDate,
                             end = endDate
        )

    },ignoreNULL = F)

    output$plot <- renderPlot({
        input$action
        rangecal <- isolate(input$dateRangeCal)
        p = data %>%
            filter(date>=rangecal[1]+days(isolate(input$week))*7,date<=rangecal[2]) %>%
            ggplot(.,aes(x=date,y=val))+
            geom_line()
        p
    })
}

shinyApp(ui, server)

Answer 2

That should do it:

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

  week <- reactiveVal()

  observeEvent( input$action, {
    week(input$week)
    startDate = as.Date("2020-01-01")+days(case_when(
      input$group == "A" ~ 0,
      input$group == "B" ~ 30,
      input$group == "C" ~ 60
    ))
    endDate=startDate+days(60)
    updateDateRangeInput(session = session, 
                         inputId = 'dateRangeCal',
                         label = 'Date range input:',
                         start = startDate,
                         end = endDate
    )

  },ignoreNULL = F)

  output$plot <- renderPlot({
    p = data %>%
      filter(date>=input$dateRangeCal[1]+days(week())*7,date<=input$dateRangeCal[2]) %>%
      ggplot(.,aes(x=date,y=val))+
      geom_line()
    p
  })
}