| # arr-union [](https://www.npmjs.com/package/arr-union) [](https://travis-ci.org/jonschlinkert/arr-union) |
| |
| > Combines a list of arrays, returning a single array with unique values, using strict equality for comparisons. |
| |
| ## Install |
| |
| Install with [npm](https://www.npmjs.com/): |
| |
| ```sh |
| $ npm i arr-union --save |
| ``` |
| |
| ## Benchmarks |
| |
| This library is **10-20 times faster** and more performant than [array-union](https://github.com/sindresorhus/array-union). |
| |
| See the [benchmarks](./benchmark). |
| |
| ```sh |
| #1: five-arrays |
| array-union x 511,121 ops/sec ±0.80% (96 runs sampled) |
| arr-union x 5,716,039 ops/sec ±0.86% (93 runs sampled) |
| |
| #2: ten-arrays |
| array-union x 245,196 ops/sec ±0.69% (94 runs sampled) |
| arr-union x 1,850,786 ops/sec ±0.84% (97 runs sampled) |
| |
| #3: two-arrays |
| array-union x 563,869 ops/sec ±0.97% (94 runs sampled) |
| arr-union x 9,602,852 ops/sec ±0.87% (92 runs sampled) |
| ``` |
| |
| ## Usage |
| |
| ```js |
| var union = require('arr-union'); |
| |
| union(['a'], ['b', 'c'], ['d', 'e', 'f']); |
| //=> ['a', 'b', 'c', 'd', 'e', 'f'] |
| ``` |
| |
| Returns only unique elements: |
| |
| ```js |
| union(['a', 'a'], ['b', 'c']); |
| //=> ['a', 'b', 'c'] |
| ``` |
| |
| ## Related projects |
| |
| * [arr-diff](https://www.npmjs.com/package/arr-diff): Returns an array with only the unique values from the first array, by excluding all… [more](https://www.npmjs.com/package/arr-diff) | [homepage](https://github.com/jonschlinkert/arr-diff) |
| * [arr-filter](https://www.npmjs.com/package/arr-filter): Faster alternative to javascript's native filter method. | [homepage](https://github.com/jonschlinkert/arr-filter) |
| * [arr-flatten](https://www.npmjs.com/package/arr-flatten): Recursively flatten an array or arrays. This is the fastest implementation of array flatten. | [homepage](https://github.com/jonschlinkert/arr-flatten) |
| * [arr-map](https://www.npmjs.com/package/arr-map): Faster, node.js focused alternative to JavaScript's native array map. | [homepage](https://github.com/jonschlinkert/arr-map) |
| * [arr-pluck](https://www.npmjs.com/package/arr-pluck): Retrieves the value of a specified property from all elements in the collection. | [homepage](https://github.com/jonschlinkert/arr-pluck) |
| * [arr-reduce](https://www.npmjs.com/package/arr-reduce): Fast array reduce that also loops over sparse elements. | [homepage](https://github.com/jonschlinkert/arr-reduce) |
| * [array-unique](https://www.npmjs.com/package/array-unique): Return an array free of duplicate values. Fastest ES5 implementation. | [homepage](https://github.com/jonschlinkert/array-unique) |
| |
| ## Contributing |
| |
| Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](https://github.com/jonschlinkert/arr-union/issues/new). |
| |
| ## Building docs |
| |
| Generate readme and API documentation with [verb](https://github.com/verbose/verb): |
| |
| ```sh |
| $ npm i verb && npm run docs |
| ``` |
| |
| Or, if [verb](https://github.com/verbose/verb) is installed globally: |
| |
| ```sh |
| $ verb |
| ``` |
| |
| ## Running tests |
| |
| Install dev dependencies: |
| |
| ```sh |
| $ npm i -d && npm test |
| ``` |
| |
| ## Author |
| |
| **Jon Schlinkert** |
| |
| * [github/jonschlinkert](https://github.com/jonschlinkert) |
| * [twitter/jonschlinkert](http://twitter.com/jonschlinkert) |
| |
| ## License |
| |
| Copyright © 2016 [Jon Schlinkert](https://github.com/jonschlinkert) |
| Released under the [MIT license](https://github.com/jonschlinkert/arr-union/blob/master/LICENSE). |
| |
| *** |
| |
| _This file was generated by [verb](https://github.com/verbose/verb), v0.9.0, on February 23, 2016._ |
