compose banner: Add specific functions to clear warnings and errors.

Instead of removing all compose banners, we now remove only warnings
and errors -- this makes no difference right now, but this change
will allow us to add other compose banners that are cleared at
different times.

frontend_tests/node_tests/lib/compose_banner.js

@@ -9,4 +9,6 @@ exports.mock_banners = () => {
     for (const classname of Object.values(compose_banner.CLASSNAMES)) {
         $(`#compose_banners .${classname}`).remove = () => {};
     }
+    $("#compose_banners .warning").remove = () => {};
+    $("#compose_banners .error").remove = () => {};
 };

static/js/compose.js

@@ -196,7 +196,8 @@ export function clear_compose_box() {
     $("#compose-textarea").removeData("draft-id");
     compose_ui.autosize_textarea($("#compose-textarea"));
     $("#compose-send-status").hide(0);
-    $("#compose_banners").empty();
+    compose_banner.clear_errors();
+    compose_banner.clear_warnings();
     compose_ui.hide_compose_spinner();
 }
 

static/js/compose_actions.js

@@ -7,6 +7,7 @@ import * as fenced_code from "../shared/js/fenced_code";
 import * as channel from "./channel";
 import * as common from "./common";
 import * as compose from "./compose";
+import * as compose_banner from "./compose_banner";
 import * as compose_fade from "./compose_fade";
 import * as compose_pm_pill from "./compose_pm_pill";
 import * as compose_state from "./compose_state";
@@ -92,7 +93,8 @@ function show_compose_box(msg_type, opts) {
         $("#private_message_toggle").addClass("active");
     }
     $("#compose-send-status").removeClass(common.status_classes).hide();
-    $("#compose_banners").empty();
+    compose_banner.clear_errors();
+    compose_banner.clear_warnings();
     $("#compose").css({visibility: "visible"});
     // When changing this, edit the 42px in _maybe_autoscroll
     $(".new_message_textarea").css("min-height", "3em");
@@ -119,7 +121,8 @@ function clear_box() {
     $("#compose-textarea").removeData("draft-id");
     compose_ui.autosize_textarea($("#compose-textarea"));
     $("#compose-send-status").hide(0);
-    $("#compose_banners").empty();
+    compose_banner.clear_errors();
+    compose_banner.clear_warnings();
 }
 
 export function autosize_message_content() {

static/js/compose_banner.ts

@@ -39,6 +39,14 @@ function hide_compose_spinner(): void {
     $("#compose-send-button").removeClass("disable-btn");
 }
 
+export function clear_errors(): void {
+    $(`#compose_banners .${ERROR}`).remove();
+}
+
+export function clear_warnings(): void {
+    $(`#compose_banners .${WARNING}`).remove();
+}
+
 export function show_error_message(message: string, classname: string, $bad_input?: JQuery): void {
     $(`#compose_banners .${classname}`).remove();
 

static/js/hotkey.js

@@ -5,6 +5,7 @@ import * as browser_history from "./browser_history";
 import * as common from "./common";
 import * as compose from "./compose";
 import * as compose_actions from "./compose_actions";
+import * as compose_banner from "./compose_banner";
 import * as compose_state from "./compose_state";
 import * as condense from "./condense";
 import * as copy_and_paste from "./copy_and_paste";
@@ -311,7 +312,8 @@ export function process_escape_key(e) {
 
             // Clear open compose banners, if present.
             if ($(".compose_banner").length) {
-                $("#compose_banners").empty();
+                compose_banner.clear_errors();
+                compose_banner.clear_warnings();
                 return true;
             }