插入排序js代码

 function insertionSort(arr) {
      if (arr.length <= 1) return arr;
      else {
        for (let i = 1; i < arr.length; ++i) {
          let value = arr[i],
            j = i - 1;
          for (; j >= 0; --j) {
            if (arr[j] > value) arr[j + 1] = arr[j];
            else break;
          }
          arr[j + 1] = value;
        }
        return arr;
      }
    }
    
    
    insertionSort([3,1,5,2,7,3,9])
    // (7) [1, 2, 3, 3, 5, 7, 9]