@extra-array/difference/README.md

Gives values of array not present in another.

Gives values of array not present in another.
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> Similar: [union], [intersection], [difference], [symmetricDifference].

> This is part of package [extra-array].

[extra-array]: https://www.npmjs.com/package/extra-array

<br>

```javascript
array.difference(x, y, [fc], [fm]);
// x:  an array
// y:  another array
// fc: compare function (a, b)
// fm: map function (v, i, x)
```
> :stopwatch: Compare function => O(n²).

```javascript
const array = require("extra-array");

var x = [1, 2, 3, 4, 5];
var y = [2, 4];
array.difference(x, y);
// [ 1, 3, 5 ]

var y = [-2, -4];
array.difference(x, y);
// [ 1, 2, 3, 4, 5 ]

array.difference(x, y, (a, b) => Math.abs(a) - Math.abs(b));
// [ 1, 3, 5 ]

array.difference(x, y, null, v => Math.abs(v));
// [ 1, 3, 5 ]
```

<br>
<br>


## References

- [Data.List.\\: Haskell](https://hackage.haskell.org/package/base-4.12.0.0/docs/Data-List.html#v:-92--92-)
- [Data.Set.difference: Haskell](http://hackage.haskell.org/package/containers-0.6.2.1/docs/Data-Set.html#v:difference)
- [Set.difference: Python](https://www.programiz.com/python-programming/methods/set/difference)
- [_.difference: lodash](https://lodash.com/docs/4.17.15#difference)
- [_.differenceBy: lodash](https://lodash.com/docs/4.17.15#differenceBy)
- [_.differenceWith: lodash](https://lodash.com/docs/4.17.15#differenceWith)
- [Array.remove: sugarjs](https://sugarjs.com/docs/#/Array/remove)

[union]: https://github.com/nodef/extra-array/wiki/union
[intersection]: https://github.com/nodef/extra-array/wiki/intersection
[difference]: https://github.com/nodef/extra-array/wiki/difference
[symmetricDifference]: https://github.com/nodef/extra-array/wiki/symmetricDifference