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Message

Source: vignettes/articles/components/message.Rmd
message.Rmd

Used to show feedback after an activity. The difference with Notification is that the latter is often used to show a system level passive notification.

Basic usage

Displays at the top by default, and disappears after 3 seconds. You can control the position using the placement property.

The setup of Message is very similar to notification, so parts of the options won’t be explained in detail here. You can check the options table below combined with notification doc to understand it. Element Plus has registered a $message method for invoking. Message can take a string or a VNode as parameter, and it will be shown as the main body.

Messages are sent from the server, el_message(session, ...).

ui <- el_page(el_button("show", "Show message", plain = TRUE))
server <- function(input, output, session) {
  observeEvent(input$show, el_message(session, "This is a message."))
}
shinyApp(ui, server)
The basic example, running

Types

Used to show the feedback of Primary, Success, Warning, Info and Error activities.

When you need more customizations, Message component can also take an object as parameter. For example, setting value of type can define different types, and its default is info. In such cases the main body is passed in as the value of message. Also, we have registered methods for different types, so you can directly call it without passing a type like open4. primary has been added in 2.9.11.

types <- c("primary", "success", "warning", "info", "error")
ui <- el_page(lapply(types, function(t) {
  el_button(paste0("m_", t), tools::toTitleCase(t), plain = TRUE)
}))
server <- function(input, output, session) {
  for (t in types) {
    local({
      t <- t
      observeEvent(
        input[[paste0("m_", t)]],
        el_message(
          session,
          paste("Congrats, this is a", t, "message."),
          type = t
        )
      )
    })
  }
}
shinyApp(ui, server)
The different-types example, running

Plain

Set plain to have a plain background.

ui <- el_page(el_button("show", "Success", plain = TRUE))
server <- function(input, output, session) {
  observeEvent(
    input$show,
    el_message(
      session,
      "Congrats, this is a success message.",
      type = "success",
      plain = TRUE
    )
  )
}
shinyApp(ui, server)
The plain example, running

Closable

A close button can be added.

A default Message cannot be closed manually. If you need a closable message, you can set showClose field. Besides, same as notification, message has a controllable duration. Default duration is 3000 ms, and it won’t disappear when set to 0.

ui <- el_page(el_button("show", "Message", plain = TRUE))
server <- function(input, output, session) {
  observeEvent(
    input$show,
    el_message(session, "This is a message.", show_close = TRUE, duration = 0)
  )
}
shinyApp(ui, server)
The closable example, running

Use HTML string

message supports HTML string.

Set dangerouslyUseHTMLString to true and message will be treated as an HTML string.

ui <- el_page(el_button("show", "Use HTML String", plain = TRUE))
server <- function(input, output, session) {
  observeEvent(
    input$show,
    el_message(
      session,
      "<strong>This is <i>HTML</i> string</strong>",
      dangerously_use_html_string = TRUE
    )
  )
}
shinyApp(ui, server)
The raw-html example, running

Warning

Although message property supports HTML strings, dynamically rendering arbitrary HTML on your website can be very dangerous because it can easily lead to XSS attacks. So when dangerouslyUseHTMLString is on, please make sure the content of message is trusted, and never assign message to user-provided content.

Grouping

merge messages with the same content.

Set grouping to true and the same content of message will be merged.

ui <- el_page(el_button("show", "Show grouping message", plain = TRUE))
server <- function(input, output, session) {
  observeEvent(
    input$show,
    el_message(session, "This is a message", grouping = TRUE, type = "success")
  )
}
shinyApp(ui, server)
The grouping example, running

Placement

Control the position where messages appear. Messages can be displayed at the top (default) or other placements of the viewport.

ui <- el_page(el_button("show", "Bottom", plain = TRUE))
server <- function(input, output, session) {
  observeEvent(
    input$show,
    el_message(session, "This is a message at the bottom", placement = "bottom")
  )
}
shinyApp(ui, server)
The placement example, running

Global method

Element Plus has added a global method $message for app.config.globalProperties. So in a vue instance you can call Message like what we did in this page.

Local import

In this case you should call ElMessage(options). We have also registered methods for different types, e.g. ElMessage.success(options). You can call ElMessage.closeAll() to manually close all the instances.

App context inheritance

Now message accepts a context as second parameter of the message constructor which allows you to inject current app’s context to message which allows you to inherit all the properties of the app.

You can use it like this:

Tip

If you globally registered ElMessage component, it will automatically inherit your app context.

API

Element Plus’s tables, and beside each entry where it is in R.

Options

Element In R Description Type Accepted Default
message message message text 1 / 2 / 3() => VNode ’’
type type message type 4'primary' (2.9.11) \\| 'success' \\| 'warning' \\| 'info' \\| 'error' info
plain plain whether message is plain 5 false
icon icon custom icon component, overrides type 6 / 7 —
dangerouslyUseHTMLString dangerously_use_html_string whether message is treated as HTML string 8 false
customClass custom_class custom class name for Message 9 ’’
duration duration display duration, millisecond. If set to 0, it will not turn off automatically 10 3000
showClose show_close whether to show a close button 11 false
onClose (JS only; Shiny hears through the id) callback function when closed with the message instance as the parameter 12() => void —
offset offset set the distance to the viewport edge (top when placement is ‘top’, bottom when placement is ‘bottom’) 13 16
placement placement message placement position 14'top' \\| 'top-left' \\| 'top-right' \\| 'bottom' \\| 'bottom-left' \\| 'bottom-right' top
appendTo append_to set the root element for the message, default to document.body 15 / 16 —
grouping grouping merge messages with the same content, type of VNode message is not supported 17 false
repeatNum repeat_num The number of repetitions, similar to badge, is used as the initial number when used with grouping 18 1