Add chat_clear() (#25)

* Add chat_clear() function

* Add NEWS

Author: cpsievert

NAMESPACE

@@ -2,6 +2,7 @@
 
 export(chat_append)
 export(chat_append_message)
+export(chat_clear)
 export(chat_ui)
 export(markdown_stream)
 export(output_markdown_stream)

NEWS.md

@@ -1,5 +1,6 @@
 # shinychat (development version)
 
+* Added a new `chat_clear()` function to clear the chat of all messages. (#25)
 * Added new `output_markdown_stream()` and `markdown_stream()` functions to allow for streaming markdown content to the client. This is useful for showing Generative AI responses in real-time in a Shiny app, outside of a chat interface. (#23)
 
 # shinychat 0.1.1

R/chat.R

@@ -387,3 +387,43 @@ rlang::on_load(chat_append_stream_impl <- coro::async(function(id, stream, role
   }
   chat_append_message(id, list(role = role, content = ""), chunk = "end", operation = "append", session = session)
 }))
+
+
+#' Clear all messages from a chat control
+#' 
+#' @param id The ID of the chat element
+#' @param session The Shiny session object
+#' 
+#' @export 
+#' @examplesIf interactive()
+#' 
+#' library(shiny)
+#' library(bslib)
+#' 
+#' ui <- page_fillable(
+#'   chat_ui("chat", fill = TRUE),
+#'   actionButton("clear", "Clear chat")
+#' )
+#' 
+#' server <- function(input, output, session) {
+#'   observeEvent(input$clear, {
+#'     chat_clear("chat")
+#'   })
+#' 
+#'   observeEvent(input$chat_user_input, {
+#'     response <- paste0("You said: ", input$chat_user_input)
+#'     chat_append("chat", response)
+#'   })
+#' }
+#'
+#' shinyApp(ui, server)
+chat_clear <- function(id, session = getDefaultReactiveDomain()) {
+  session$sendCustomMessage(
+    "shinyChatMessage",
+    list(
+      id = id,
+      handler = "shiny-chat-clear-messages",
+      obj = NULL
+    )
+  )
+}