Fallback to room name "empty room"

src/js/room-picker.js

@@ -106,9 +106,13 @@ class Room extends ElemJS {
 		}
 		// if the room has no alias, use the names of its members ("heroes")
 		const users = this.data.summary["m.heroes"]
+		if (users && users.length) {
 			const usernames = users.map(u => (u.match(/^@([^:]+):/) || [])[1] || u)
 			return usernames.join(", ")
 		}
+		// the room is empty
+		return "Empty room"
+	}
 
 	getIcon() {
 		const avatar = this.data.state.events.find(e => e.type === "m.room.avatar")