useRoomsData.js

import {useEffect, useRef} from "react";
import { useStateValue } from "./StateProvider";
import db from "./firebase";

export default function useRoomsData() {
    const [{ roomsData: initRoomsData }, dispatch] = useStateValue();
    const roomsData = useRef(initRoomsData)

    useEffect(() => {
        roomsData.current = initRoomsData;
    }, [initRoomsData])
    
    return [function setRoomsData(userID, roomID) {
        if (!roomsData.current[roomID]) {
            const lastMessageListener = db.collection("rooms").doc(roomID).onSnapshot(doc => {
                //console.log("last message listener executed with room id: ", roomID)
                dispatch({
                    type: "update_rooms_data",
                    dataType: "lastMessage",
                    data: doc.data()?.lastMessage,
                    roomID
                });
            });
            const onlineStateListener = db.collection("users").doc(userID).onSnapshot(doc => {
                //console.log("onlineState listener executed with room id: ", roomID)
                dispatch({
                    type: "update_rooms_data",
                    dataType: "onlineState",
                    data: doc.data()?.state,
                    roomID
                });
            });
            dispatch({
                type: "add_rooms_data",
                roomID,
                lastMessageListener: lastMessageListener,
                onlineStatelistener: onlineStateListener 
            });
        };
    }];
};