@extra-array/union

Gives values present in any array.
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> Alternatives: [union], [union$].

> Similar: [union], [intersection], [difference], [symmetricDifference].

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

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

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

var y = [-2, -3, -5];
array.union(x, y, (a, b) => Math.abs(a) - Math.abs(b));
// [ 1, 2, 3, 4, -5 ]

array.union(x, y, null, v => Math.abs(v));
// [ 1, 2, 3, 4, -5 ]
``

References

- Data.Set.union: Haskell
- Set.union: Python
- _.union: lodash
- _.unionBy: lodash
- _.unionWith: lodash
- Array.union: sugarjs

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