Median of two sorted arrays implementation. For Leet Code.

Leet Code: median-of-two-sorted-arrays

var findMedianSortedArrays = function(nums1, nums2) {
// new tactic, merge sort the two arrays, and then find the median.
  let sorted = mergeSort(nums1.concat(nums2));
  if (sorted.length % 2 === 0) {
    return handleEven(sorted);
  } 
  return handleOdd(sorted);
}

function mergeSort(arr) {
  // cut array down to singletons
    if (arr.length < 2)
        return arr;
    // break down the middle
    var middle = parseInt(arr.length / 2);
    // slice the left
    var left   = arr.slice(0, middle);
    // slice the right
    var right  = arr.slice(middle, arr.length);
 // throw into the call stack of merge what your cutting up
    return merge(mergeSort(left), mergeSort(right));
}
 
function merge(left, right) {
  // keep the results
    var result = [];
 // as long as both left and right slices contain elements, compare
    while (left.length && right.length) {
        if (left[0] <= right[0]) {
          // add to the results the smaller element
            result.push(left.shift());
        } else {
            result.push(right.shift());
        }
    }
    // add to the results the leftovers of the longer array
    while (left.length)
        result.push(left.shift());
 
    while (right.length)
        result.push(right.shift());
 
    return result;
}

function handleOdd(array) {
  // find the middle number
  return array[Math.floor(array.length / 2)];
}

function handleEven(array) {
  return (array[Math.floor(array.length /2)] + array[Math.floor(array.length /2) - 1]) / 2;
}