socket.to(socket.id).emit(...) does not emit to himself

You want to:

• report a bug
• request a feature

Current behaviour

We are developing a card game for Android. We have a lobby system. When every player in the lobby is ready the game will start. The client who last send the ready-event triggers the startGame() function, which first generates the cards for all clients and then sends the client’s card deck to them. Following source code is handling the sending to the clients:

dealCards(socket) {
  for (let i = 0; i < this.getNumPlayers; i++) {
    // get playercards out of the card deck
    let cards = [];
    for (let j = i; j <= this.cardDeck.length - (this.getNumPlayers - i); j += this.getNumPlayers) {
      cards.push(this.cardDeck[j]);
    }

    this.players[i].setCards(cards);

    // emit cards to player
    socket.to(this.players[i].getSocketId).emit(EVENT.LOBBY.START_GAME, {
      cards: cards,
    });
  }
}

But the client who triggered startGame() is not receiving the start_game-event. When we emit the event like in the following source code it works:

dealCards(socket) {
  for (let i = 0; i < this.getNumPlayers; i++) {
    [...]

    // emit cards to player
    if (this.players[i].getSocketId === socket.id) {
      socket.emit(EVENT.LOBBY.START_GAME, {
        cards: cards,
      });
    } else {
      socket.to(this.players[i].getSocketId).emit(EVENT.LOBBY.START_GAME, {
        cards: cards,
      });
    }
  }
}

Steps to reproduce

A failing and working testing case can be found here.

1. start the server npm run client
2. start some clients in different consoles to fill the ‘lobby’ npm run client
3. point your browser to http://localhost:3000

After pressing the button Trigger Error`` you should see a log message at client's cosnole but not in the browser sonsole. After pressing the button Trigger Working` you should see a log message in all clients console.

Expected behaviour

When using socket.to(id).emit(...) the event should be emitted to the calling socket too. So in my opinion:

// sending to individual socketid (private message)
socket.to(socket.id).emit('hey', 'I just met you');

should act like:

// sending to the client
socket.emit('hey', 'I just met you');

Setup

• OS: macOS 10.13.1 (Node v8.9.1), Debian 8 (Node v6.11.3)
• Android Client: 1.0.0
• socket.io version: 2.0.3

[darrachequesne]

@TimmePfeife I added a note in the documentation: https://socket.io/docs/emit-cheatsheet/

I’m closing this now, please do not hesitate if you see any further improvement: https://github.com/socketio/socket.io-website.

[gregpalaci]

I just figured this out the docs are wrong socket.to(socket.id).emit('hey', 'i just met you') should actually be socket.emit(('hey', 'i just met you') where socket is the parent socket

io.on('connection', function(socket) { 
  const user = socket;  
  user.emit('hey', 'I just met you') 
}