# # 349 Intersection of Two Arrays

[LeetCode](https://leetcode.com/problems/intersection-of-two-arrays/)

```
Given two arrays, write a function to compute their intersection.
output: 回傳交集的元素
```

```
Example 1:

Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2]
Example 2:

Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [9,4]
Note:

Each element in the result must be unique.
The result can be in any order.

/**
 * @param {number[]} nums1
 * @param {number[]} nums2
 * @return {number[]}
 */
var intersection = function(nums1, nums2) {
   
};
```

### 怎麼解

交集就想到 Set，送分題

```
var intersection = function(nums1, nums2) {
    let nums1Map = new Set(nums1);
    let result = new Set();
    nums2.forEach(item => {
        if(nums1Map.has(item)){
            result.add(item)
        }
    })
    return [...result];
};
// faster than 99.94% of JavaScript online submissions
```

