Socket.io在连接事件上的调用确认

Question

Is there any way too utilize the ack argument on the connect event in Node.js? Something like this:

//client.js
socket.on('connect', (data) => {
  console.log(data); // I want to print 'lol' here
});

//server.js
io.on('connect', (socket, ack) => {
  ack('lol'); // TypeError: ack is not a function
});

Reference for ack: https://socket.io/docs/server-api/#socket-emit-eventname-args-ack

Answer 1

There is no specific ack data that you can send for the connect event. You can just .emit() a message to the client when the server receives the connect.

//client.js
socket.on('connect', () => {
  console.log('client connected');
});

socket.on('welcome', function(data) {
  console.log(data); // 'lol'
});

//server.js
io.on('connect', (socket) => {
  // send welcome message upon connect
  socket.emit('welcome', 'lol');
});

Answer 2

It doesn't look like the socket.connect() or socket.open() methods take an ack argument. I generally will emit a 'connected' event from the server once a connection from the client is established. You can receive this emission and add your behavior as needed.

server.js

io.on('connect', function(socket) {
  socket.emit('connected');
});

client.js

socket.on('connected', function() {
  console.log('Connected');
});