Untitled

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <script>
    Function.prototype.memoized = function (key) {
        this._value = this._value || {};

        return this._value[key] !== undefined ?
            this._value[key] :
            this._value[key] = this.apply(this, arguments);
    };

    Function.prototype.memoize = function () {
        var fn = this;
        return function() {
            return fn.memoized.apply(fn, arguments);
        }
    }

    var isPrime = (function (number) {
        var prime = number != 1;

        for (var i = 2; i < number; i++) {
            if (number % i === 0) {
                prime = false;
                break;
            }
        }

        return prime;
    }).memoize();

    console.log(isPrime(23));
    // console.log(isPrime._value[23]);
    </script>
</body>
</html>