Chunk Array 陣列切割分塊

Given an array arr and a chunk size size, return a chunked array. A chunked array contains the original elements in arr, but consists of subarrays each of length size. The length of the last subarray may be less than size if arr.length is not evenly divisible by size.

You may assume the array is the output of JSON.parse. In other words, it is valid JSON.

Please solve it without using lodash's _.chunk function.

Example 1:

Input: arr = [1,2,3,4,5], size = 1
Output: [[1],[2],[3],[4],[5]]
Explanation: The arr has been split into subarrays each with 1 element.

Example 2:

Input: arr = [1,9,6,3,2], size = 3
Output: [[1,9,6],[3,2]]
Explanation: The arr has been split into subarrays with 3 elements. However, only two elements are left for the 2nd subarray.

Example 3:

Input: arr = [8,5,3,2,6], size = 6
Output: [[8,5,3,2,6]]
Explanation: Size is greater than arr.length thus all elements are in the first subarray.

Example 4:

Input: arr = [], size = 1
Output: []
Explanation: There are no elements to be chunked so an empty array is returned.

Constraints:

arr is a valid JSON array
2 <= JSON.stringify(arr).length <= 105
1 <= size <= arr.length + 1

解法：

這是在講給定一個陣列，跟他指定要分每個區塊的數量

遍例陣列，在讀他分塊的數量有無有存在，有就把el推進去這個塊，沒有在推一個空塊的並把當前el帶入

const chunk = (arr: any[], size: number) => {
    const res: any[][] = [];
    for(let i = 1; i <= arr.length; i++){
        const scope = Math.ceil(i/size) - 1;
        if(res[scope]){
            res[scope].push(arr[i - 1]);
        }else{
            res.push([arr[i - 1]]);
        }
    }
    return res;
};