socket io session map - node.js

Question

Hello on entering my backend I make a connection to my socket and send the player data + socket id
good, and then on receiving I add him in line
and perform a function that will fetch 2 players who have approximate points to form a match
and so I wanted to find a match send to the socket of the selected players
But I don't know how best to map session
I saw about express.socket-io
or save one of these socket's that connect in some way
for when I find a match
send my match to my selected socket's
io.on('connection', function (socket) {
//ADD PLAYER TO QUEUE
socket.on('addPlayer-Queue', (result) => {
const player = {
id: result.id,
name: result.name,
mmr: result.mmr
}
const player = new Player(player,socketid )
socket.emit('match', matches)
});
class Player {
constructor(player,socketId) {
this.id = player.id
this.socketId = socketId
this.name = player.name
this.mmr = player.mmr
}
}
Here I get my player and create it, but I don't know how to get this player's socket.id and how to map in a session

Answer 1

If I understood you correctly, here's a way to do it.
Everytime a players get added, I push them on an array and then call the function matchPlayersQueue that tries to match players based on their MMR (I haven't completed the code, but a way to do it, is either check the variance of MMRs or check their difference). If you follow this path, keep in mind that everytime a players disconnect that was on the queue array, you should remove the element.
Another way to do this is, set a timer that periodically calls the function matchPlayersQueue.
let playersOnQueue = [];
io.on("connection", function(socket) {
//ADD PLAYER TO QUEUE
socket.on("addPlayer-Queue", result => {
const player = {
id: result.id,
name: result.name,
mmr: result.mmr
};
const player = new Player(player, socketid);
playersOnQueue.push(player);
const matchedPlayers = matchPlayersQueue(playersOnQueue); // matchedPlayers will be an array of their sockets ids.
// Do something with matchedPlayers, empty playersOnQueue if matchedPlayers.length doesn't equal to 0.
});
});
function matchPlayersQueue(arr) {
//We'll sort the array by mmr.
arr.sort(function(firstPlayer, secondPlayer) {
return firstPlayer.getMMR() - secondPlayer.getMMR();
});
if (arr.length >= 3) {
//Trivial way to match 3 people, not checking for MMR.
if (arr.length === 3) {
const socketIDs = arr.map(function(player) {
return player.getSocketID();
});
return socketIDs;
} else {
/*
Here you can implement your own way of selecting players, maybe having a maximum MMR difference between players or comparing the overall variance of MMR.
*/
}
} else {
//If there are fewer than 3 people.
return [];
}
}
class Player {
/*
Beware of this constructor, while this works, The way i'd would do it is each variable to their own attribute.
*/
constructor(player, socketId) {
this.id = player.id;
this.socketId = socketId;
this.name = player.name;
this.mmr = player.mmr;
}
getMMR() {
return this.mmr;
}
getSocketID() {
return this.socketId;
}
}