Sometimes,. we want to send a message to a particular client with Node.js socket.io.

In this article, we’ll look at how to send a message to a particular client with Node.js socket.io.

How to send a message to a particular client with Node.js socket.io?

To send a message to a particular client with Node.js socket.io, we can call sockets.in before calling emit.

For instance, we write

const socket = io.connect('http://localhost');
socket.emit('join', {
  email: '[email protected]'
});

on client side to connect to the socket.io server.

Then on server side, we write

const io = require('socket.io').listen(80);

io.sockets.on('connection', (socket) => {
  socket.on('join', (data) => {
    socket.join(data.email);
    io.sockets.in('[email protected]').emit('msg', {
      msg: 'hello'
    })
  });
});

to create a socket.io server.

And we listen for 'join' events that are emitted by clients.

We get the data from the object in the 2nd argument of emit from data.

Then we call io.sockets.in with '[email protected]' and then call emit to send data to the client with email '[email protected]'

Conclusion

To send a message to a particular client with Node.js socket.io, we can call sockets.in before calling emit.