gcd

Calculates the greatest common divisor between two or more numbers/arrays.

• The inner _gcd function uses recursion.
• Base case is when y equals 0. In this case, return x.
• Otherwise, return the GCD of y and the remainder of the division x/y.

const gcd = (...arr) => {
  const _gcd = (x, y) => (!y ? x : gcd(y, x % y));
  return [...arr].reduce((a, b) => _gcd(a, b));
};

gcd(8, 36); // 4
gcd(...[12, 8, 32]); // 4