Given an array of integers, find the largest product yielded from three of the integers

var unsortedArray = [-10, 7, 29, 30, 5, -10, -70];

computeProduct(unsortedArray); // 21000

function sortIntegers(a, b) {
   return a - b;
}

// Greatest product is either (min1 * min2 * max1 || max1 * max2 * max3)
function computeProduct(unsorted) {
   var sortedArray = unsorted.sort(sortIntegers),
       product1 = 1,
       product2 = 1,
       array_n_element = sortedArray.length - 1;

   // Get the product of three largest integers in sorted array
   for (var x = array_n_element; x > array_n_element - 3; x--) {
       product1 = product1 * sortedArray[x];
   }

   product2 = sortedArray[0] * sortedArray[1] * sortedArray[array_n_element];

   if (product1 > product2) return product1;

   return product2;
}