Get a list of current clients with usernames - socket.io

Question

I am making a simple chat, so when someone logs on I have this:
socket.broadcast.emit('logon', {
socketID: socket.id,
username: username
});
So if I login via chrome as "Bob", and then I log in via Edge as "Ted", I will see "Ted" when "Ted" logs in and I am looking at the chat with chrome.
But how do I get the list of current clients with usernames as soon as I log in?
So if "Ted" is already there, and I log in as "Bob" from a different browser, I want to see "Ted" in the list.
Is it possible to do without using a database to store each user that logs in, as that is the only way I can think of but would prefer not to use a database?

Answer 1

There is no need to use a database. The only thing you must have is an array of users that is connected to certain event listeners server side. Example:
var users = []; // Array of users online
io.on('connection', function(socket) {
var user = { // On connection, create an object for the user.
socket: socket,
username: null
}
socket.on("login",function(data) { // When the user logs in, set his username and add him to the users array.
user.username = data.username;
users.push(user);
});
socket.on("disconnect",function() { // When user disconnects, remove the object from the array.
var index = users.indexOf(user);
if (index !== -1) users.splice(index);
});
});
As you can see, there is now an array of all online users that you can access.