js new Function()的執行區域問題

var x = 'outside';

function y() {
    var x = 'inside';

    var code = "if(typeof x === 'undefined'){\
        console.log('no x');\
    }else{\
        console.log(x);\
    }";

    return (new Function('data', code));
}

var fn = y();

console.log(fn.toString());
fn();
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瀏覽器 => x = "outside"
node.js => undefined