Find bigger common divisor for two numbers

BiggerCommonDivisor.js

const biggerCommonDivisor = (a, b) => {

  const findDivisor = (a, b, z) => {
    console.log(z);
    if (a % z === 0 && b % z === 0)
      return z;
      else
      return findDivisor(a, b, z - 1);
  };

  if (b > a)
    return findDivisor(b, a, b);
  else
  	return findDivisor(a, b, a);
};

export default biggerCommonDivisor;