JS错误（预期为类，接口或枚举）

Question

I am new to JS and trying to make a Rock, Paper, Scissors Game...

It keeps on coming up with this error

error: class,interface, or enum expected

Here is my code:

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));

Answer 1

Object.keys(training); is only supported in Chrome

Change

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

to

function choices() {
   var keys = [];
   for(var key in this) keys.push(key);
   return keys;
}

Answer 2

Instead of just placing the return at the end, you might want to make it a function. Right now your "ref" variable holds an array, since that's what the referee function returns.

I see Hitham S. AlQadheeb has beat me to the answer lol!