Insertion Sort
Traversal in Binary Tree：

將下一順位(j = i + 1)的陣列數值與當前(i)、過去(j--)的陣列數值進行大小比對，
符合則交換位置。

Input: nums = [1, 2, 3, 2, 1, 6]

let insertionSort = (nums) => {
  let length = nums.length;

  for (let i = 1; i < length; i++) {
    let current = nums[i];
    let j = i - 1;

    //如果 nums[i] 小於之前的元素，則進行交換。
    while ((j > -1) && (current < nums[j])) {
      nums[j + 1] = nums[j];
      j--;
    }
    nums[j + 1] = current;
  }
  return nums;
}

Output: newNums = [1, 1, 2, 2, 3, 6]

Flow Chart:

[ 1, 2, 3, 2, 1, 6 ]
[ 1, 2, 3, 2, 1, 6 ]
[ 1, 2, 2, 3, 1, 6 ]
[ 1, 1, 2, 2, 3, 6 ]
[ 1, 1, 2, 2, 3, 6 ]
[ 1, 1, 2, 2, 3, 6 ]

Blog：http://52.198.119.162/關於insertion-sort排序方法與示意圖/