GameMaker

/// Create Event: nothing is connected yet
 
client = 0;
net_room = 0;

/// Step Event: connect once the extension is ready, then poll every frame
 
if (client == 0) {
    if (!colyseus_is_ready()) exit;
 
    client = colyseus_client_create("http://localhost:2567");
    net_room = colyseus_client_join_or_create(client, "my_room", "{}");
    net_setup_handlers(net_room);   // see below
}
 
colyseus_process();
 
if (colyseus_room_is_connected(net_room)) {
    var _dx = keyboard_check(vk_right) - keyboard_check(vk_left);
    var _dy = keyboard_check(vk_down) - keyboard_check(vk_up);
    if (_dx != 0 || _dy != 0) {
        x += _dx * 4;
        y += _dy * 4;
        colyseus_send(net_room, "move", { x: x, y: y });
    }
}

/// Room event handlers. Called from the object's Step event, so the
/// function literals below are bound to that instance and can store
/// instance variables (player_objs, callbacks).
 
function net_setup_handlers(net_room) {
 
    colyseus_on_join(net_room, function(_room) {
        show_debug_message("Joined room: " + colyseus_room_get_id(_room));
        show_debug_message("Session ID: " + colyseus_room_get_session_id(_room));
 
        // Store as instance variables (no "var") so nested callbacks can access them
        player_objs = {};
        callbacks = colyseus_callbacks_create(_room);
 
        // Listen to root state properties (instance can be omitted for root)
        colyseus_listen(callbacks, "currentTurn", function(value, prev) {
            show_debug_message("Turn changed: " + string(prev) + " -> " + string(value));
        });
 
        // Listen for players added to the "players" map
        colyseus_on_add(callbacks, "players", function(instance, key) {
            show_debug_message("Player joined: " + key);
 
            var _px = colyseus_schema_get(instance, "x");
            var _py = colyseus_schema_get(instance, "y");
            var _player_obj = instance_create_depth(_px, _py, 0, obj_player);
 
            player_objs[$ key] = _player_obj;
 
            // GML anonymous functions can access instance variables (like "callbacks"),
            // but NOT outer local variables (declared with "var").
            // Use method() to pass local variables into nested callbacks:
            colyseus_listen(callbacks, instance, "x", method({ obj: _player_obj }, function(v, p) {
                obj.x = v;
            }));
            colyseus_listen(callbacks, instance, "y", method({ obj: _player_obj }, function(v, p) {
                obj.y = v;
            }));
        });
 
        // Listen for players removed from the map
        colyseus_on_remove(callbacks, "players", method({ objs: player_objs }, function(instance, key) {
            show_debug_message("Player left: " + key);
            if (variable_struct_exists(objs, key)) {
                instance_destroy(objs[$ key]);
                delete objs[$ key];
            }
        }));
    });
 
    colyseus_on_error(net_room, function(code, msg) {
        show_debug_message("Room error [" + string(code) + "]: " + msg);
    });
 
    colyseus_on_leave(net_room, function(code, reason) {
        show_debug_message("Left room [" + string(code) + "]: " + reason);
    });
 
    colyseus_on_message(net_room, function(_room, _type, _data) {
        // _data is auto-decoded: struct for maps, string/number/bool for primitives
        show_debug_message("Message [" + _type + "]: " + json_stringify(_data));
    });
 
}

/// Clean Up Event: free resources
 
if (net_room != 0) {
    colyseus_room_leave(net_room);
    colyseus_room_free(net_room);  // also frees associated callbacks
}
if (client != 0) {
    colyseus_client_free(client);
}

git clone https://github.com/colyseus/sdks-test-server
cd sdks-test-server
npm install
npm start

import { defineServer } from "colyseus";
import { WebSocketTransport } from "@colyseus/ws-transport";
 
const server = defineServer({
    // ...
    transport: new WebSocketTransport({
        pingInterval: 0,
    }),
    // ...
});