Unity3D Socket.IO Basic Movement Latency - node.js

Question

I'm trying to make a server using with Node.JS and Socket.IO. I want to make an online game that just has simple movement event. I wrote some code, but it doesn't work very well. I have tonnes of latencies. You can check the video in below. By the way, I test it on my DigitalOcean servers or even in my LocalHost. What is the trick about my problem? I really would like to learn Network programming but I always get stuck.
Latency GAMEPLAY YouTube Link -- Especially check 13th seconds
Project GitHub link
I will explain all of my works on below. But If you want to check details codes. You can visit GitHub project link.
On the client side, I used Unity3D. If user key press to any arrow keys like upArrow, rightArrow than I send this information to the Server. By doing so the server knows which direction I would like to go.
if (Input.GetKey(KeyCode.UpArrow))
{
Movement = Vector3.up;
JSONObject data = new JSONObject();
data.AddField("x", Movement.x);
data.AddField("y", Movement.y);
socket.Emit("move", data);
}
// if Input.GetKey(KeyCode.RightArrow)
// if Input.GetKey(KeyCode.RightArrow) .. etc
On the server side, I just used Node JS and Socket.IO. I create an interval function that only sends all players to clients. This interval function fires 60 times every 1 seconds. You can see the code in below.
setInterval(function() {
io.emit('state', players);
}, 1000 / 60);
By the way, when the server receives any move event it does this:
socket.on('move', function(data) {
var player =players[socket.id] ||{};
player.x =player.x+(data.x*0.1);
player.y =player.y+(data.y*0.1);
});

Answer 1

You need to move also locally. So when emitting the "move" command on client side also start moving the player on client side. If you receive new information from the server, merge them. The keyword is interpolation.

Answer 2

First off, you do not need an interval, unless you are doing real time physic simulations on the server in node.
Second think of node.js more in an event driven manner. I.E. only send update to other players when a player makes an action nearby them.
Third use client side prediction. I.E. go ahead and move the player on the client even though the server hasn't received it yet. Then interpolate based on the last position that the server said was valid. A simple linear interpolation will work just fine if you send a time stamp from server.
Fourth, ditch socket io. Socket io is notoriously slow when it comes to websockets. If you want to use websockets then I recommend using just the node library WS. The WS library is efficient and fast. Or if you want an event driven library like socket io but based on WS library. Then you can try my custom library that I use and has been tested in multiple online based games: https://github.com/Metric/data.io. I still actively maintain it and will be pushing out an update to the c# client in a couple of weeks. The update to the c# client fixes some issues that I found while using it in a new project recently.
However, tcp would be more efficient than websockets. Websockets have an increased overhead compared to just a raw tcp or udp connection. Yes, you will still get a delay and will still need client side prediction.
For further info on networking and prediction see: http://gafferongames.com/networking-for-game-programmers/
He covers all the concepts with some code examples as well.
Also see: https://developer.valvesoftware.com/wiki/Source_Multiplayer_Networking