const nums1 = [1, 2, 2, 1], nums2 = [2] 交集是什么？

The intersection of nums1 = [1, 2, 2, 1] and nums2 = [2] is [2].

While nums1 contains two instances of the number 2, an intersection only includes distinct elements present in both arrays. Since 2 is the only element present in both, the resulting intersection is [2].