findDifference = function (nums1, nums2) {
    const nums1Set = new Set(nums1);
    const nums2Set = new Set(nums2);

    const lst1 = Array.from(nums1Set).filter((num) => !nums2Set.has(num));
    const lst2 = Array.from(nums2Set).filter((num) => !nums1Set.has(num));

    return [lst1, lst2];
}
@param {number[]} nums1
@param {number[]} nums2
@return {number[][]}