Find the Greatest Common Divisor of two numbers

recursive-version.js

function gcd(n, m) {
  if (!m) { return n; }
  return (m, n % m);
}

console.log(gcd(512, 1024)); // 256

regular-version.js

function isEven(num) {
  return num % 2 === 0;
}

function findDevisors(num) {
  var result = [], max = isEven(num) ? num / 2 : Math.floor(num / 2);
  for (var i = 2; i <= max; i++) {
  	if (num % i === 0) {
      result.push(i);
    }
  }
  return result;
}

function commonTwoArrays(a, b) {
  var result = [];
  a.forEach(function(item) {
    if (b.indexOf(item) !== -1) {
      result.push(item);
    }
  });
  return result;
}

function gcd(n, m) {
  var nList = findDevisors(n);
  var mList = findDevisors(m);
  var commonList = commonTwoArrays(nList, mList);

  return Math.max.apply(null, commonList);
}

console.log(gcd(512, 1024)); // 256