---
title: Check if two arrays intersect
type: snippet
language: javascript
tags: [array]
author: chalarangelo
cover: interior-5
dateModified: 2023-02-17T05:00:00-04:00
---

Determines if two arrays have a common item.

- Create a `Set` from `b` to get the unique values in `b`.
- Use `Array.prototype.some()` on `a` to check if any of its values are contained in `b`, using `Set.prototype.has()`.

```js
const intersects = (a, b) => {
  const s = new Set(b);
  return [...new Set(a)].some(x => s.has(x));
};
```

```js
intersects(['a', 'b'], ['b', 'c']); // true
intersects(['a', 'b'], ['c', 'd']); // false
```