Add DESIRED_NAME Message

ServerMessage.ts

@@ -5,6 +5,7 @@ export enum MessageType {
   TYPING = 4,
   CURRENTLY_TYPING = 5,
   CONNECTED_USERS = 6,
+  DESIRED_NAME = 7,
 }
 
 export type ServerMessage = {
@@ -175,3 +176,21 @@ export function isConnectedUsersMessage(
 
   return true;
 }
+
+export type DesiredNameMessage = ServerMessage & {
+  type: MessageType.DESIRED_NAME;
+  desiredName: string;
+};
+export function isDesiredNameMessage(obj: unknown): obj is DesiredNameMessage {
+  if (!isServerMessage(obj, MessageType.DESIRED_NAME)) {
+    return false;
+  }
+  if (
+    !Object.hasOwnProperty.call(obj, "desiredName") ||
+    typeof (obj as ServerMessage & { desiredName: unknown }).desiredName !==
+      "string"
+  ) {
+    return false;
+  }
+  return true;
+}