插入排序

const insertSort = (arr) => {
  const len = arr.length

  // 从第二个元素开始遍历
  for  (let i = 1; i < len; i ++ ) {

    const ele = arr[i]

    // 索引i位置的值依次跟前面的元素比
    for (let j = i - 1; j >= 0; j --) {

      const  cur =  arr[j]
      const  next = arr[j + 1]

      if(cur < ele) {
        break
      }

      arr[j] =  next
      arr[j+1] = cur
    }

  }

  return arr
}