Function sendMessage

src/components/SendMessage.js:8–24

(event)

  const [message, setMessage] = useState("");

  const sendMessage = async event => {
    event.preventDefault();
    const trimmed = message.trim();
    if (!trimmed) {
      alert("Enter valid message");
      return;
    }
    if (!roomId) {
      alert("Select a room to send messages");
      return;
    }
    const { uid, displayName, photoURL } = auth.currentUser;
    await addDoc(collection(db, "rooms", roomId, "messages"), {
      text: trimmed,
      name: displayName,
      avatar: photoURL,
      createdAt: serverTimestamp(),
      uid,
    });
    setMessage("");