其他情况下

io.of('/chat').on('connection', function (socket) {
    //sending to all clients in 'room' and you
    io.of('/chat').in('room').emit('message', "data");
};

发出备忘单

io.on('connect', onConnect);

function onConnect(socket){

  // sending to the client
  socket.emit('hello', 'can you hear me?', 1, 2, 'abc');

  // sending to all clients except sender
  socket.broadcast.emit('broadcast', 'hello friends!');

  // sending to all clients in 'game' room except sender
  socket.to('game').emit('nice game', "let's play a game");

  // sending to all clients in 'game1' and/or in 'game2' room, except sender
  socket.to('game1').to('game2').emit('nice game', "let's play a game (too)");

  // sending to all clients in 'game' room, including sender
  io.in('game').emit('big-announcement', 'the game will start soon');

  // sending to all clients in namespace 'myNamespace', including sender
  io.of('myNamespace').emit('bigger-announcement', 'the tournament will start soon');

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

  // sending with acknowledgement
  socket.emit('question', 'do you think so?', function (answer) {});

  // sending without compression
  socket.compress(false).emit('uncompressed', "that's rough");

  // sending a message that might be dropped if the client is not ready to receive messages
  socket.volatile.emit('maybe', 'do you really need it?');

  // sending to all clients on this node (when using multiple nodes)
  io.local.emit('hi', 'my lovely babies');

};

V4.x中的服务器端所有有效发射事件列表

io.on("connection", (socket) => {

// basic emit
socket.emit(/* ... */);

// to all clients in the current namespace except the sender
socket.broadcast.emit(/* ... */);

// to all clients in room1 except the sender
socket.to("room1").emit(/* ... */);

// to all clients in room1 and/or room2 except the sender
socket.to(["room1", "room2"]).emit(/* ... */);

// to all clients in room1
io.in("room1").emit(/* ... */);

// to all clients in room1 and/or room2 except those in room3
io.to(["room1", "room2"]).except("room3").emit(/* ... */);

// to all clients in namespace "myNamespace"
io.of("myNamespace").emit(/* ... */);

// to all clients in room1 in namespace "myNamespace"
io.of("myNamespace").to("room1").emit(/* ... */);

// to individual socketid (private message)
io.to(socketId).emit(/* ... */);

// to all clients on this node (when using multiple nodes)
io.local.emit(/* ... */);

// to all connected clients
io.emit(/* ... */);

// WARNING: `socket.to(socket.id).emit()` will NOT work, as it will send to everyone in the room
// named `socket.id` but the sender. Please use the classic `socket.emit()` instead.

// with acknowledgement
socket.emit("question", (answer) => {
    // ...
});

// without compression
socket.compress(false).emit(/* ... */);

// a message that might be dropped if the low-level transport is not writable
socket.volatile.emit(/* ... */);

});

客户端

// basic emit
    socket.emit(/* ... */);

// with acknowledgement
    socket.emit("question", (answer) => {
        // ...
    });

// without compression
    socket.compress(false).emit(/* ... */);

// a message that might be dropped if the low-level transport is not writable
    socket.volatile.emit(/* ... */);

存档链接到source => http://archive.today/2021.06.22-023900/https://socket.io/docs/v4/emit-cheatsheet/index.html

广播。Emit将MSG发送到所有其他客户端(发送方除外)

socket.on('cursor', function(data) {
  socket.broadcast.emit('msg', data);
});

这里是一个更完整的答案，关于从0.9改变了什么。X到1.x。

 // send to current request socket client
 socket.emit('message', "this is a test");// Hasn't changed

 // sending to all clients, include sender
 io.sockets.emit('message', "this is a test"); // Old way, still compatible
 io.emit('message', 'this is a test');// New way, works only in 1.x

 // sending to all clients except sender
 socket.broadcast.emit('message', "this is a test");// Hasn't changed

 // sending to all clients in 'game' room(channel) except sender
 socket.broadcast.to('game').emit('message', 'nice game');// Hasn't changed

 // sending to all clients in 'game' room(channel), include sender
 io.sockets.in('game').emit('message', 'cool game');// Old way, DOES NOT WORK ANYMORE
 io.in('game').emit('message', 'cool game');// New way
 io.to('game').emit('message', 'cool game');// New way, "in" or "to" are the exact same: "And then simply use to or in (they are the same) when broadcasting or emitting:" from http://socket.io/docs/rooms-and-namespaces/

 // sending to individual socketid, socketid is like a room
 io.sockets.socket(socketid).emit('message', 'for your eyes only');// Old way, DOES NOT WORK ANYMORE
 socket.broadcast.to(socketid).emit('message', 'for your eyes only');// New way

我想编辑@soyuka的帖子，但我的编辑被同行评审拒绝了。

已为Socket更新。io v4.0.0 +

要发送到除v4中的sender外的所有客户端，您可以使用:

socket.broadcast.emit(/* ... */);

示例使用

io.on("connection", (socket) => {
   socket.on("message", (message) => {
      //sends "newMessage" to all sockets except sender
      socket.broadcast.emit("newMessage", message)
   })
})