| # arr-diff [](https://www.npmjs.com/package/arr-diff) [](https://npmjs.org/package/arr-diff) [](https://travis-ci.org/jonschlinkert/arr-diff) |
| |
| > Returns an array with only the unique values from the first array, by excluding all values from additional arrays using strict equality for comparisons. |
| |
| ## Install |
| |
| Install with [npm](https://www.npmjs.com/): |
| |
| ```sh |
| $ npm install --save arr-diff |
| ``` |
| |
| Install with [yarn](https://yarnpkg.com): |
| |
| ```sh |
| $ yarn add arr-diff |
| ``` |
| |
| Install with [bower](https://bower.io/) |
| |
| ```sh |
| $ bower install arr-diff --save |
| ``` |
| |
| ## Usage |
| |
| Returns the difference between the first array and additional arrays. |
| |
| ```js |
| var diff = require('arr-diff'); |
| |
| var a = ['a', 'b', 'c', 'd']; |
| var b = ['b', 'c']; |
| |
| console.log(diff(a, b)) |
| //=> ['a', 'd'] |
| ``` |
| |
| ## Benchmarks |
| |
| This library versus [array-differ](https://github.com/sindresorhus/array-differ), on April 14, 2017: |
| |
| ``` |
| Benchmarking: (4 of 4) |
| · long-dupes |
| · long |
| · med |
| · short |
| |
| # benchmark/fixtures/long-dupes.js (100804 bytes) |
| arr-diff-3.0.0 x 822 ops/sec ±0.67% (86 runs sampled) |
| arr-diff-4.0.0 x 2,141 ops/sec ±0.42% (89 runs sampled) |
| array-differ x 708 ops/sec ±0.70% (89 runs sampled) |
| |
| fastest is arr-diff-4.0.0 |
| |
| # benchmark/fixtures/long.js (94529 bytes) |
| arr-diff-3.0.0 x 882 ops/sec ±0.60% (87 runs sampled) |
| arr-diff-4.0.0 x 2,329 ops/sec ±0.97% (83 runs sampled) |
| array-differ x 769 ops/sec ±0.61% (90 runs sampled) |
| |
| fastest is arr-diff-4.0.0 |
| |
| # benchmark/fixtures/med.js (708 bytes) |
| arr-diff-3.0.0 x 856,150 ops/sec ±0.42% (89 runs sampled) |
| arr-diff-4.0.0 x 4,665,249 ops/sec ±1.06% (89 runs sampled) |
| array-differ x 653,888 ops/sec ±1.02% (86 runs sampled) |
| |
| fastest is arr-diff-4.0.0 |
| |
| # benchmark/fixtures/short.js (60 bytes) |
| arr-diff-3.0.0 x 3,078,467 ops/sec ±0.77% (93 runs sampled) |
| arr-diff-4.0.0 x 9,213,296 ops/sec ±0.65% (89 runs sampled) |
| array-differ x 1,337,051 ops/sec ±0.91% (92 runs sampled) |
| |
| fastest is arr-diff-4.0.0 |
| ``` |
| |
| ## About |
| |
| ### Related projects |
| |
| * [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 "Recursively flatten an array or arrays. This is the fastest implementation of array flatten.") |
| * [array-filter](https://www.npmjs.com/package/array-filter): Array#filter for older browsers. | [homepage](https://github.com/juliangruber/array-filter "Array#filter for older browsers.") |
| * [array-intersection](https://www.npmjs.com/package/array-intersection): Return an array with the unique values present in _all_ given arrays using strict equality… [more](https://github.com/jonschlinkert/array-intersection) | [homepage](https://github.com/jonschlinkert/array-intersection "Return an array with the unique values present in _all_ given arrays using strict equality for comparisons.") |
| |
| ### Contributing |
| |
| Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new). |
| |
| ### Contributors |
| |
| | **Commits** | **Contributor** | |
| | --- | --- | |
| | 33 | [jonschlinkert](https://github.com/jonschlinkert) | |
| | 2 | [paulmillr](https://github.com/paulmillr) | |
| |
| ### Building docs |
| |
| _(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_ |
| |
| To generate the readme, run the following command: |
| |
| ```sh |
| $ npm install -g verbose/verb#dev verb-generate-readme && verb |
| ``` |
| |
| ### Running tests |
| |
| Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command: |
| |
| ```sh |
| $ npm install && npm test |
| ``` |
| |
| ### Author |
| |
| **Jon Schlinkert** |
| |
| * [github/jonschlinkert](https://github.com/jonschlinkert) |
| * [twitter/jonschlinkert](https://twitter.com/jonschlinkert) |
| |
| ### License |
| |
| Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert). |
| Released under the [MIT License](LICENSE). |
| |
| *** |
| |
| _This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.5.0, on April 14, 2017._ |
