roster kind of sort of works

priv/static/js/dist/webrtc.d.ts

@@ -10,5 +10,7 @@
  * @module
  */
 declare function main(): Promise<void>;
+type ws_msg = ["username", string] | ["users", Array<string>];
+declare function handle_ws_msg(message: ws_msg, roster_ul: HTMLUListElement, whoami: HTMLHeadingElement): void;
 declare function handle_join(init: HTMLDivElement, init_name: HTMLInputElement, peers: HTMLDivElement, ws: WebSocket): Promise<void>;
 declare function ws_send_json(ws: WebSocket, x: any): void;