function pow(base, power) {

  if (power === 0) {

    return 1;

  }

​

  if (power % 2 === 0) {

    const multiplier = pow(base, power / 2);

    return multiplier * multiplier;

  }

​

  const multiplier = pow(base, Math.floor(power / 2));

  return multiplier * multiplier * base;

}

​

var a = pow(2,20)

function pow2(x, y) {

    var q = parseInt((y / 2), 10);

    if (y % 2 !== 0) {

        return (x ** q) * (x ** q) * x; 

    }

    return (x ** q) * (x ** q); 

}

var a = pow2(2,20)