Given an array of integers arr and an integer n, return a subarray of arr of length n where the sum is the largest. Make sure you maintain the order of the original array

maxSubArray.ts

const maxSubArray = (arr: number[], len: number) =>
  arr.length < len
    ? []
    : arr
        .map((_, index, a) => a.slice(index, index + len))
        .filter(a => a.length === len)
        .sort((arr1, arr2) => Math.max(...arr2) - Math.max(...arr1))[0]