Factorial = function (value)
{
    if (value === 0)
    {
        return 1;
    }

    var res = value;

    while (--value)
    {
        res *= value;
    }

    return res;
}
Calculates the factorial of a given number for integer values greater than 0.

@function Phaser.Math.Factorial
@since 3.0.0

@param {number} value - A positive integer to calculate the factorial of.

@return {number} The factorial of the given number.