product, two version

product.md

var product2 = function product2(nums) {
var result = 1;

  for (var i = 0; i < nums.length; i++) {
    result *= nums[i];
  }

  return result;

};

var product = function product () {
  var result = 1;

  // the arguments object contains all arguments passed
  // to the function
  // it has a length property and it elements
  // can be accessed with []

  for (var i = 0; i < arguments.length; i++) {
    result *= arguments[i];
  }

  return result;
};