compose_ui: Add "(guest)" to user names in compose box placeholder.

This commit adds "(guest)" indicator to guest user names in
compose box placeholder if enable_guest_user_indicator setting
is enabled in the organization.

web/src/compose_ui.js

@@ -252,6 +252,9 @@ export function compute_placeholder_text(opts) {
         const recipient_names = recipient_list
             .map((recipient) => {
                 const user = people.get_by_email(recipient);
+                if (people.should_add_guest_user_indicator(user.user_id)) {
+                    return $t({defaultMessage: "{name} (guest)"}, {name: user.full_name});
+                }
                 return user.full_name;
             })
             .join(", ");

web/tests/compose_ui.test.js

@@ -6,6 +6,7 @@ const {$t} = require("./lib/i18n");
 const {mock_esm, set_global, zrequire} = require("./lib/namespace");
 const {run_test} = require("./lib/test");
 const $ = require("./lib/zjquery");
+const {page_params} = require("./lib/zpage_params");
 
 const noop = () => {};
 
@@ -248,6 +249,19 @@ run_test("compute_placeholder_text", () => {
         compose_ui.compute_placeholder_text(opts),
         $t({defaultMessage: "Message Alice, Bob"}),
     );
+
+    alice.is_guest = true;
+    page_params.realm_enable_guest_user_indicator = true;
+    assert.equal(
+        compose_ui.compute_placeholder_text(opts),
+        $t({defaultMessage: "Message translated: Alice (guest), Bob"}),
+    );
+
+    page_params.realm_enable_guest_user_indicator = false;
+    assert.equal(
+        compose_ui.compute_placeholder_text(opts),
+        $t({defaultMessage: "Message Alice, Bob"}),
+    );
 });
 
 run_test("quote_and_reply", ({override, override_rewire}) => {