How to get the value of variable from another R script

I'm working on a dashboard with the shiny library and I've managed to create a function that tells me which tab I'm on currently. The problem is that I can't call this function with my other script

library(shiny)

# Define UI for application that draws a histogram
ui <- fluidPage(
  
  # Application title
  titlePanel("test"),
  
  # Sidebar with a slider input for number of bins 
  sidebarLayout(
    sidebarPanel(
      sliderInput("bins",
                  "Number of bins:",
                  min = 1,
                  max = 50,
                  value = 30)
    ),
    
    # Show a plot of the generated distribution
    mainPanel(
      plotOutput("distPlot"),
      
      # Output: Tabset w/ plot, summary, and table
      tabsetPanel(id = "tabs",
                  tabPanel("Plot", plotOutput("ID1")),
                  tabPanel("Summary", verbatimTextOutput("ID2")),
                  tabPanel("Table", tableOutput("ID3")),
      )
    )
  ))

# Define server logic required to draw a histogram
server <- function(input, output) {
  
  observeEvent(input$tabs, {
    print(paste("You clicked tab:", input$tabs))
  })
}
# Run the application 
shinyApp(ui, server)

In the other program, I tried to call the function but it didn't succeed.

  
  source("C:/Users/Downloads/Rshiny-intro/RestAPI_TabPanels/App.R")
  
  observeEvent(input$tabs, {
    print(paste("You clicked tab:", input$tabs))
  })
} ```