函数不适用于Socket.io

Question

I'm trying to send an array from a server that contains all the IDs of the users when someone connects on the server using socket io. Apparently, the emitting part seems to work properly, but the receiving part is not responding at all.

io.sockets.on('connection',
// here's the on connection event
function (socket) {
  i++;
  ids[i]=socket.id;
  console.log("We have a new client: " + ids[i]);
  socket.broadcast.emit('setid', ids);
}
/////that is the emitting part

now this is the receiving part:

 socket.on('setid',
   function(ids) {
  console.log(ids);
 }
);

Answer 1

You need to change socket.broadcast.emit('setid', ids); to socket.broadcast.emit('setid', {idArr:ids}); and console.log(ids.idArr); on the receiving function.

as someone asked,

Sever

io.on('connection',
// here's the on connection event
function (socket) {
  let i = 0;
  let ids = [];
  i++;
  ids[i]=socket.id;
  console.log("We have a new client: " + ids[i]);
  socket.broadcast.emit('setid', {
    idArr:ids
  });
}

Client

socket.on('setid', function(ids) {
  console.log(ids.idArr);
 }
);

As a side note as It wasn't completely clear here, using socket.broadcast.emit shall emit to all clients except the socket sending the emit So until you open another client instance it won't emit.

Answer 2

Look at the following example, it is very simple, just the socket.io server and the socket.io-client client (you may have to run npm install socket.io-client first):

khalil-server.js

const io = require('socket.io')(3001);
var ids = [];
io.on('connection', function (socket) {
    'use strict';
    ids.push(socket.id);
    console.log("We have a new client: " + socket.id);
    socket.broadcast.emit('setid', ids);
});
console.log('Server started at port 3001');

khalil-client.js

const socket = require('socket.io-client')('http://localhost:3001');
socket.on('setid', function (ids) {
    console.log(ids);
});

Start the server with node khalil-server and as many clients as you can with node khalil-client (you will have to run at least two client instances because we use the socket.broadcast.emit ). It just works. Please show us more of your code and we will try to find a bug.