"The further a society drifts from the truth, the more it will hate those that speak it." - George Orwell

cassidoo Challenge 2-18

function minimumDiff(arr) {
  var sortedArr = mergeSort(arr),
      difference = sortedArr[1] - sortedArr[0];
    
  for (var i = 1; i < sortedArr.length; i++) {
    if (sortedArr[i] - sortedArr[i - 1] < difference) {
      difference = sortedArr[i] - sortedArr[i - 1];
    }
  }
    
  return difference;
}

function mergeSort(arr) {
  if (arr.length < 2) return arr;
    
  var middle = Math.floor(arr.length / 2),
      left = arr.slice(0, middle),
      right = arr.slice(middle);
    
  return merge(
    mergeSort(left),
    mergeSort(right)
  );
}

function merge(left, right) {
  var result = [],
      indexLeft = 0,
      indexRight = 0;
    
  while (indexLeft < left.length && indexRight < right.length) {
    if (left[indexLeft] < right[indexRight]) {
      result.push(left[indexLeft]);
      indexLeft++;
    } else {
      result.push(right[indexRight]);
      indexRight++;
    }
  }
    
  return result.concat(left.slice(indexLeft)).concat(right.slice(indexRight));
}

minimumDiff([130, 5, 20, 9]);