test leaflet with dashboard: app1.r is working, but app2.R gives an error in console (Couldn't find map with id map)

app1.R

library(shiny)
library(shinydashboard)
# header board
header <- dashboardHeader(
    title = 'Pheno-Copter'
    # task list for status of data processing
    , dropdownMenuOutput('task_menu'))

# Side bar board
sidebar <- dashboardSidebar(
    sidebarMenu(
        id = 'menu_tabs'
        , menuItem('menu1', tabName = 'menu1')
        , menuSubItem('menu2', tabName = 'menu2')
        
    )
)

# Body board
body <- dashboardBody(
    tabItems(
        tabItem(
            tabName = 'menu1'
            , tags$a(
                id = "mydiv", href = "#", 'click me', 
                onclick = 'Shiny.onInputChange("mydata", Math.random());'),
            leafletOutput('map')
        ),
        tabItem(
            tabName = 'image_viewer'
        )
    )
)

# Shiny UI
ui <- dashboardPage(
    title = 'test',
    dashboardHeader(),
    sidebar,
    body
)

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

    output$map <- renderLeaflet({
        leaflet() %>%  
            addTiles(options = tileOptions(maxZoom = 28, maxNativeZoom = 19),
                                group = 'OSM')
    })
    observe({
        input$mydata
        proxy <- leafletProxy('map')
        proxy %>% 
            setView(runif(1) * 10, runif(1) * 10, 7)
    })
}

shinyApp(ui, server)

app2.R

library(shiny)
library(shinydashboard)


# header board
header <- dashboardHeader(
    title = 'Pheno-Copter'
    # task list for status of data processing
    , dropdownMenuOutput('task_menu'))

# Side bar board
sidebar <- dashboardSidebar(
    sidebarMenu(
        id = 'menu_tabs'
        , menuItem('menu1', tabName = 'menu1')
        , menuSubItem('menu2', tabName = 'menu2')
        
    )
)

# Body board
body <- dashboardBody(
    tabItems(
        tabItem(
            tabName = 'menu1'
            , tags$a(
                id = "mydiv", href = "#", 'click me', 
                onclick = 'Shiny.onInputChange("mydata", Math.random());')
        ),
        tabItem(
            tabName = 'image_viewer'
        ),
        tabItem(
            tabName = 'menu2'
            , leafletOutput('map')
        )
    )
)

# Shiny UI
ui <- dashboardPage(
    title = 'test',
    dashboardHeader(),
    sidebar,
    body
)

server <- function(input, output, session) {
    observe({
       req(input$mydata)
       updateTabItems(session, 'menu_tabs', 'menu2')
    })
    output$map <- renderLeaflet({
        leaflet() %>%  
            addTiles(options = tileOptions(maxZoom = 28, maxNativeZoom = 19),
                                group = 'OSM')
    })
    observe({
        input$mydata
        proxy <- leafletProxy('map')
        proxy %>% 
            setView(runif(1) * 10, runif(1) * 10, 7)
    })
}


shinyApp(ui, server)

app3.R

library(leaflet)
library(shiny)
library(shinydashboard)


# header board
header <- dashboardHeader(
    title = 'Pheno-Copter'
    # task list for status of data processing
    , dropdownMenuOutput('task_menu'))

# Side bar boardy
sidebar <- dashboardSidebar(
    sidebarMenu(
        id = 'menu_tabs'
        , menuItem('menu2', tabName = 'menu2')
        
        , menuItem('menu1', tabName = 'menu1')
        
    )
)

# Body board
body <- dashboardBody(
    tabItems(
        
        tabItem(
            tabName = 'menu1'
            , tags$a(
                id = "mydiv", href = "#", 'click me', 
                onclick = 'Shiny.onInputChange("mydata", Math.random());')
        ),
        tabItem(
            tabName = 'menu2'
            , leafletOutput('map')
            , verbatimTextOutput('summary')
        )
    )
)

# Shiny UI
ui <- dashboardPage(
    title = 'test',
    dashboardHeader(),
    sidebar,
    body
)

server <- function(input, output, session) {
    observe({
        req(input$mydata)
        updateTabItems(session, 'menu_tabs', 'menu2')
    })
    output$map <- renderLeaflet({
        leaflet() %>%  
            addTiles(options = tileOptions(maxZoom = 28, maxNativeZoom = 19),
                     group = 'OSM')
    })
    output$summary <- renderPrint({
        print(input$mydata)
        print(leafletProxy('map')$id)
    })
    observe({
        req(input$mydata)
        proxy <- leafletProxy('map')
        print(proxy$id)
        proxy %>% 
            setView(runif(1) * 30 +2, runif(1) * 30 + 2, 7)
    })
}


shinyApp(ui, server)