30-seconds-of-code/snippets/arrayGcd.md

arrayGcd

Calculates the greatest common denominator (gcd) of an array of numbers.

Use Array.reduce() and the gcd formula (uses recursion) to calculate the greatest common denominator of an array of numbers.

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

arrayGcd([1, 2, 3, 4, 5]); // 1
arrayGcd([4, 8, 12]); // 4