无法在课堂上遍历this.array

Question

我有以下课程，我想遍历this.player，但无法使其正常工作。

  

我从最小的例子开始

在server.js中按以下方式调用游戏

 const Game = require("./Game");
let game = new Game(io);
game.launch();

Game.js

class Game {
     constructor(io) {
        this.io = io; //socket.io
        this.users = [];
    }
    waitForPlayers() {
        let interval = setInterval(() => {
            let size = Object.keys(this.users).length;
            if (size >= 1) {
                clearInterval(interval);
                this.gameloop();
            }
        }, 2000)
    }
    gameloop() {
        setInterval(() => {
            for (let i in this.users) {
                console.log(this.users[i]);
            }
        })
    }
    launch() {
        this.io.on("connection", socket => {
            socket.on("createUser", (arr) => {
                this.createUser(socket, arr);
            });
        });
        this.waitForPlayers();
    }
    createUser(socket, arr) {
        this.users[socket.id] = socket;
        this.users[socket.id].username = arr[0]; 
    }

}

我在做什么错或我不明白什么？
Old Version