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30-seconds-of-code/snippets/difference.md
2017-12-28 08:30:19 +00:00

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### difference
Returns the difference between two arrays.
Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values not contained in `b`.
```js
const difference = (a, b) => {
const s = new Set(b);
return a.filter(x => !s.has(x));
};
```
```js
difference([1, 2, 3], [1, 2, 4]); // [3]
```