I work at a chat application. I want to store messages in an object like this :
{
'room1': ['msg1', 'msg2', ...]
'room2': ['msg3', 'msg4', ...]
...
}
I defined a variable in my socket.io server roomMessages
the problem is when I want to add a message in a specific room using roomMessages[room].push(data); it shows me this error: TypeError: Cannot read properties of undefined (reading 'push')
this is my socket.io code:
const roomMessages = {};
roomsNamespace.use((socket, next) => {
const token = socket.handshake.query.token;
console.log(token);
if (!token) return next(new Error("not auth"));
next();
});
roomsNamespace.on("connection", (socket) => {
const token = socket.handshake.query.token;
const apiService = new ApiService(process.env.BE_URL, token);
const room = socket.handshake.query.room;
socket.on("join-room", async () => {
socket.join(room);
await apiService.joinRoom(room);
const usersInThisRoom = await apiService.getUsersInRoom(room);
roomsNamespace.in(room).emit("all-users", usersInThisRoom);
socket.emit("room-messages", roomMessages[room]);
});
socket.on("chat-message", (data) => {
// console.log(data);
if (roomMessages[room]) roomMessages[room].push(data);
roomsNamespace.in(room).emit("chat-message", data);
});
basically, I want to send previous messages when user joins the chat How to fix this error?
you can do something like this
const roomMessages = {};
const getMessages = (room) => roomMessages[room] || []
const addMessage = (room, message) => {
roomMessages[room] = [...getMessages(room), message]
}
roomsNamespace.use((socket, next) => {
const token = socket.handshake.query.token;
console.log(token);
if (!token) return next(new Error("not auth"));
next();
});
roomsNamespace.on("connection", (socket) => {
const token = socket.handshake.query.token;
const apiService = new ApiService(process.env.BE_URL, token);
const room = socket.handshake.query.room;
socket.on("join-room", async () => {
socket.join(room);
await apiService.joinRoom(room);
const usersInThisRoom = await apiService.getUsersInRoom(room);
roomsNamespace.in(room).emit("all-users", usersInThisRoom);
socket.emit("room-messages", getMessages(room));
});
socket.on("chat-message", (data) => {
// console.log(data);
addMessage(room, data)
roomsNamespace.in(room).emit("chat-message", data);
});
in this way if you want later you can change your implementation of messageRepository storing data in redis or wherever you want