Check if users are active

Community Usage questions
2

You could create a custom module to filter outgoing messages and decide whether they should be ignored or not based on the client's past activity, something like

// keep track of connected clients

var clients = {}

app.on('open', (data, client)=>{
    if (!clients[client.id]) clients[client.id] = {
        active: false, // inactive by default ?
        some_stat: 0 // keep track of client's activity one way or another
    }
})

app.on('close', (data, client)=>{
    // you might want to remove this part
    // 'close' could be emitted upon browser reload
    // and setting the 'active' flag manually in oscOutFilter should suffice 
    if (clients[client.id]) delete clients[client.id]
})

module.exports = {

    oscOutFilter:function(data){

        var {address, args, host, port, clientId} = data

        // use outgoing message to determine if client is active ?
        if (some_conditions_are_met) {
            clients[clientId].active = true
        }

        if (!clients[clientId].active) return // silence inactive clients ?

        return {address, args, host, port}

    }

}