InOut = function (v)
{
    if ((v *= 2) < 1)
    {
        return 0.5 * Math.pow(2, 10 * (v - 1));
    }
    else
    {
        return 0.5 * (2 - Math.pow(2, -10 * (v - 1)));
    }
}
Exponential ease-in/out.

@function Phaser.Math.Easing.Expo.InOut
@since 3.0.0

@param {number} v - The value to be tweened.

@return {number} The tweened value.