What is the correct way to send notifications to multiple tabs using socket.io?

Question

Yii

Friends, good afternoon.
Faced a very interesting task (perhaps only for me). I implement notifications using socket.io, redis. All this is spinning on yii2.
Essence of the question. When sending a notification to a user, notifications are duplicated. The number of duplicate notifications depends on the number of open tabs.
Client part. Here we create a room for the user and subscribe to notifications.

var socket = io();
socket.emit("join", {"room": userRoom});
socket.on("notify", function (data) {
     $( "#notifications" ).prepend(data.message);
});

Server part.

io.on('connection', function (socket) {
        var redisClient = redis.createClient(6379, 'redis');
        redisClient.subscribe('notify');
        redisClient.on("message", function(channel, message) {
            var res = JSON.parse(message);
            io.sockets.in(res.room).emit(channel, {msg: res.message});
        });
        socket.on('disconnect', function() {
            redisClient.quit();
        });
    });

How the notification is sent.

Yii::$app->redis->executeCommand('PUBLISH', [
    'channel' => 'notify',
    'message' => \yii\helpers\Json::encode(['room' => 'room', 'message' => 'hello'])
]);

Actually works well. But the more I open browser tabs, the more I get duplicate messages in one tab. For example, I have 5 tabs open. I initiate executeCommand once and pass hello message. Thus, in each of the 5 tabs, 5 words "Hello" appear. At the same time, I look through the redis-cli monitor and see that only one notification is being created.
Thanks in advance for the hint.
Thanks