Javascript JS错误（需要类、接口或枚举）

我是JS的新手，正在尝试制作一个石头、布、剪刀的游戏

它不断地出现这个错误

error: class,interface, or enum expected

这是我的密码：

function referee(){

    var training = {};

    function learn(winner,loser){
        if (!training[winner]) training[winner] = {};
        training[winner][loser]=1;
    }

    function judge(play1,play2){
        if (play1 === play2){ return "tie"; }
        return ( (training[play1][play2] === 1)? play1: play2 )+ "wins!";
    }

    function validate(choice) {
        return choice in training;
    }

    function choices() {
        return Object.keys(training);
    }

    return {
        "learn": learn,
        "judge": judge,
        "validAction": validate,
        "getChoices": choices
    };
}



var ref = referee();
ref.learn("rock","scissors");
ref.learn("paper","rock");
ref.learn("scissors","paper");

do {
   var userChoice = prompt("Do you choose rock, paper or scissors?");
} while(!ref.validAction(userChoice))

var choices = ref.getChoices(),
computerChoice = choices[Math.floor(Math.random()*choices.length)];

console.log("User Choice: " + userChoice); 
console.log("Computer Choice: " + computerChoice);
console.log(ref.judge(userChoice, computerChoice));

Object.key（训练）仅在Chrome中受支持

改变

function choices() {
    return Object.keys(training);
}

到

您可能希望使其成为一个函数，而不是将return放在末尾。现在，您的“ref”变量包含一个数组，因为这是仲裁函数返回的结果

我看到希瑟姆·S·阿尔卡德希布已经击败我找到了答案，哈哈
 我看到您正在将
reference
用作一个类，而它没有被解释为一个类。请参考指南了解js中的OO概念。
function choices() {
   var keys = [];
   for(var key in this) keys.push(key);
   return keys;
}