Error Handling

Added ability to handle errors R-side.

library(shiny)
library(communicate)

add <- \(x, y){
  x + y + "error" # this will cause an error
} 

err <- \(error){
  cat("Aaaaah, an error!\n")
  print(error)
}

# more on JavaScript error handling in the JavaScript page
script <- "
  $('#btn').on('click', () => {
    communicate.com('add', {x: 1})
      .then(res => alert(`equals: ${res}`))
      .catch(error => alert('There was an error')); # catch error
  })
"

ui <- fluidPage(
  # import dependencies
  useCommunicate(),
  h1("Hello"),
  tags$a("Communicate", id = "btn"),
  tags$script(HTML(script))
)

server <- \(input, output, session){
  com("add", add)(x = Integer, y = Numeric)(y = 1.1)(err)
}

shinyApp(ui, server)